Honey is a pantry staple that can be safe to eat for ages. But does honey ever go bad? And why is honey so resistant to spoiling?

It appears that this thick, sticky, sweet nectar owes its properties to chemicals imparted by its makers — honeybees. Astonishingly, there are at least 300 types of honey known today that are produced by more than 20,000 honeybee species.

"The composition of the honey depends on the type of honeybees," Kantha Shelke, a food scientist at Johns Hopkins University and founder of Corvus Blue LLC, a food science and nutrition research firm based in Chicago, told Live Science in an email. 

After collecting nectar from flowers, bees turn the sucrose, a complex mix of glucose and fructose, into highly concentrated simple sugars. While honey is mostly sugars, it also contains more than a dozen other substances, such as enzymes, minerals, vitamins and organic acids. Honey also contains flavonoid and phenolic compounds, which are known to be anti-inflammatory and antioxidants. These compounds are responsible for honey's medicinal properties. 

The multitude of chemicals that coalesce when honeybees create honey makes this natural sweetener inhospitable to microbes that usually spoil food. 

Honey's high sugar content makes it hygroscopic, meaning it can suck moisture from the environment, and even absorb the water from surrounding microbial cells. Honey also has a low level of available water in which microbes can grow. 

After turning flower nectar into simple sugars, bees regurgitate the sweet liquid and pass it on to other bees in the hive. As the nectar sits inside the bees' stomachs, glucose oxidase breaks down the glucose and turns it into gluconic acid and hydrogen peroxide. When the bees finally place and fan the digested nectar in the comb, water slowly evaporates and turns this sweet liquid viscous. 

Related: How do bees make honey? From the hive to the pot

The presence of gluconic, as well as acetic, formic, and citric acid, makes honey even more acidic than coffee. This pH range is lower than what most microbes can tolerate. And the hydrogen peroxide in honey may stop bacteria from forming a slimy network called biofilm that usually sticks to surfaces.

All of these chemicals stop microbes from degrading honey. But while honey remains safe to consume for a long period, it does change over time. 

"Honey constituents undergo changes because of crystallization, fermentation, oxidation, and thermal effects. The changes also depend on the type of honey (light or dark) and source, or region which vary with the season and the plants foraged by the honeybee," Shelke said. "Some of these changes influence the nutritional and sensory attributes including appearance."

When heated or stored for a long time, honey can undergo a Maillard reaction, the same chemical reaction that caramelizes sugar and turns it brown. As sugars become dehydrated, they produce a potentially toxic compound, 5-hydroxymethylfurfural (HMF). HMF is also found in many other food products including breakfast cereals, dried fruits and milk. 

The safe levels of HMF for daily consumption are still poorly understood. Some research has suggested HMF can fuel cancer, while others suggest the compound can prevent allergic reactions. The Codex Alimentarius Standard, an international standard on food safety, has set an upper limit of 40 mg/kg HMF for honey products. But this limit varies among the different types of honey. For instance, sunflower honey can reach this HMF limit after being properly stored for 18 months, while acacia honey takes about five years to reach the same amount of HMF.

Heating leads to HMF production, but cooling causes honey to crystallize. As honey cools, the sugar content becomes too saturated and unable to stay in solution. This can also happen when moisture escapes the honey during storage, causing the sugars to form crystals, Shelke said. 

According to one study, the sensory and chemical properties of honey are best preserved when stored at 75 degrees Fahrenheit (24 degrees Celsius), or around room temperature.

Because of all these variables, "handling and packaging can greatly affect the shelf life of honey," Shelke said. "Raw honey — with intact enzymes and other beneficial compounds — is minimally processed and can last 'forever' if stored in a sealed container."

Likewise, pasteurized honey can last several years. But because it lacks some of the enzymes and antimicrobial compounds, it may be susceptible to microbial damage if not sealed or stored properly, Shelke added. 

Of note, caretakers should avoid feeding honey to infants, because spores from the bacterium Clostridium botulinum can contaminate honey. These spores can withstand pasteurization temperatures. Once ingested, they can release a toxin into babies' intestines and cause infant botulism, a condition that can be fatal. The spores are generally harmless to adults as their mature digestive systems purge the toxin. 

This article is for informational purposes only and is not meant to offer medical advice.

Drinking lots of artificially sweetened beverages, such as diet sodas, comes with a 20% higher risk of an irregular heartbeat, a new study finds. 

The research also revealed that consuming similar amounts of sugar-sweetened drinks was linked to a 10% bump in risk. Adults who reported drinking at least 2 liters, or roughly 67 ounces, of sweetened drinks a week saw these jumps in risk, compared to people who drank none. 

However, the study found only an association between these beverages and irregular heartbeats — it can't say that sugar or artificial sweeteners actually cause the heart condition.

Related: Is Diet Coke bad for you? 

In the study, published Tuesday (March 5) in the journal Circulation: Arrhythmia and Electrophysiology, researchers reviewed self-reported diet data from about 202,000 people in the U.K. Biobank, a repository of genetic and health data from half a million U.K.-based participants. 

Over an average of nearly 10 years for each participant, the researchers checked to see who developed atrial fibrillation, or AFib for short. 

This type of arrhythmia occurs when the upper chambers of the heart beat irregularly. AFib can cause blood clots and heart failure, and it's the leading cause of stroke, CNN reported.  

People who consumed the equivalent of one 12-ounce artificially sweetened drink a day saw the greatest risk of AFib, compared to those who drank no sweetened beverages. These drinks were sweetened with ingredients such as sucralose, aspartame, saccharin and acesulfame.

However, adults who drank 1 liter (34 ounces) or less of pure juice with no added sugars, such as 100% orange or vegetable juice, had an 8% lower risk of the condition than those who drank artificially sweetened beverages, according to an American Heart Association (AHA) statement.    

"This is the first study to report an association between no- and low-calorie sweeteners and also sugar-sweetened beverages and increased risk of atrial fibrillation," Penny Kris-Etherton, a member of the AHA's nutrition committee who was not involved in the study, said in the statement. 

"While there is robust evidence about the adverse effects of sugar-sweetened beverages and cardiovascular disease risk, there is less evidence about adverse health consequences of artificial sweeteners," she said.

Some evidence has linked beverages made with sugar substitutes to an increased risk of heart attack and stroke. 

In addition, in 2023, an arm of the World Health Organization (WHO) declared aspartame a "possible carcinogen," although the organization's process of identifying possible cancer-causing agents is fraught with problems. But the U.S. Food and Drug Administration (FDA) disagrees with the WHO's stance, stating that it hasn't found any link between aspartame and cancer. 

Because the new study only observed people's beverage consumption habits, it could not demonstrate that artificial sweeteners or sugar actually cause AFib. For instance, it's possible that some underlying factors predispose people to both drink more diet soda and have the heart condition.

"Although the mechanisms linking sweetened beverages and atrial fibrillation risk are still unclear, there are several possible explanations, including insulin resistance and the body's response to different sweeteners," lead study author Dr. Ningjian Wang, a researcher at the Shanghai Ninth People's Hospital and Shanghai Jiao Tong University School of Medicine in China, said in the AHA statement.

"We still need more research on these beverages to confirm these findings and to fully understand all the health consequences on heart disease and other health conditions," Kris-Etherton added. "In the meantime, water is the best choice, and, based on this study, no- and low-calorie sweetened beverages should be limited or avoided."

This article is for informational purposes only and is not meant to offer medical advice.

Ever wonder why some people build muscle more easily than others or why freckles come out in the sun? Send us your questions about how the human body works to community@livescience.com with the subject line "Health Desk Q," and you may see your question answered on the website!

Humans are not the only mammals that love sugar. Fruit bats do, too, eating up to twice their body weight in sugary fruit a day. However, unlike humans, fruit bats thrive on a sugar-rich diet. They can lower their blood sugar faster than bats that rely on insects as their main food source.

We are a team of biologists and bioengineers. Determining how fruit bats evolved to specialize on a high-sugar diet sent us on a quest to approach diabetes therapy from an unusual angle — one that sent us all the way to Lamanai, Belize, for the Belize Bat-a-thon, an annual gathering where researchers collect and study bats.  Diabetes, the ninth leading cause of death in 2019, can emerge when the body is unable to process sugar effectively, leading to excess glucose in the blood. 

In our newly published research in Nature Communications, we and colleagues Seungbyn Baek and Martin Hemberg used a technology that analyzes the DNA of individual cells to compare the unique metabolic instructions encoded in the genome of the Jamaican fruit bat, Artibeus jamaicensis, with those in the genome of the insect-eating big brown bat, Eptesicus fuscus.

Approximately 2% of DNA is composed of genes, which are segments of DNA that contain the instructions cells use to create certain traits, such as a longer tongue in fruit bats. The other 98% are segments of DNA that regulate genes and determine the presence and absence of the traits they encode.

To understand how fruit bats evolved to consume so much sugar, we wanted to identify the genetic and cellular differences between bats that eat fruit and bats that eat insects. Specifically, we looked at the genes, regulatory DNA and cell types in two significant organs involved in metabolic disease: the pancreas and the kidney.

The pancreas regulates blood sugar and appetite by secreting hormones like insulin, which lowers your blood sugar, and glucagon, which raises your blood sugar. We found Jamaican fruit bats have more insulin-producing and glucagon-producing cells than big brown bats, along with regulatory DNA that primes fruit bat pancreatic cells to initiate production of insulin and glucagon. Together these two hormones work to keep blood sugar levels balanced even when the fruit bats are eating large amounts of sugar.

The kidney filters metabolic waste from the blood, maintains water and salt balance and regulates blood pressure. Fruit bat kidneys need to be equipped to remove from their bloodstreams the large amounts of water that come from fruit while retaining the low amounts of salt in fruit. We found Jamaican fruit bats have adjusted the compositions of their kidney cells in accordance with their diet, reducing the number of urine-concentrating cells so their urine is more diluted with water compared with big brown bats.

Why it matters

Diabetes is one of the most expensive chronic conditions in the world. The U.S. spent US$412.9 billion in 2022 on direct medical costs and indirect costs related to diabetes.

Most approaches to developing new treatments for diabetes are based on traditional laboratory animals such as mice because they are easy to reproduce and study in a lab. But outside the lab, there exist mammals like fruit bats that have actually evolved to withstand high sugar loads. Figuring out how these mammals deal with high sugar loads can help researchers identify new approaches to treat diabetes.

By applying new cell characterization technologies on these nonmodel organisms, or organisms researchers don't usually use for research in the lab, we and a growing body of researchers show that nature could be leveraged to develop novel treatment approaches for disease.

What still isn't known

While our study revealed many potential therapeutic targets for diabetes, more research needs to be done to demonstrate whether our fruit bat DNA sequences can help understand, manage or cure diabetes in humans.

Some of our fruit bat findings may be unrelated to metabolism or are specific only to Jamaican fruit bats. There are close to 200 species of fruit bats. Studying more bats will help researchers clarify which fruit bat DNA sequences are relevant for diabetes treatment.

Our study also focused only on bat pancreases and kidneys. Analyzing other organs involved in metabolism, such as the liver and small intestine, will help researchers more comprehensively understand fruit bat metabolism and design appropriate treatments.

What's next

Our team is now testing the regulatory DNA sequences that allow fruit bats to eat so much sugar and checking whether we can use them to better regulate how people respond to glucose.

We are doing this by swapping the regulatory DNA sequences in mice with those of fruit bats and testing their effects on how well these mice manage their glucose levels.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Dentists say to "brush twice a day" to prevent sticky plaque from building up on your teeth and raising the risk of cavities. But how does plaque cause cavities, exactly?

The link between plaque and tooth decay largely stems from how the bacteria in plaque interact with the foods we eat. However, factors such as a person's age and whether they smoke or take certain medications can also play a role in plaque-driven tooth decay.

For background, plaque is a colorless film of bacteria that sticks to the surface of teeth and also catches bits of food in the mouth. To start forming a film, plaque microbes first embed themselves among proteins found in the saliva on a tooth's surface.

Cavities, or areas of tooth decay, tend to happen when foods rich in sugars and starchy carbohydrates — such as candy, honey, bread or cereals — come into contact with plaque bacteria, Dr. Purnima Kumar, a professor at the University of Michigan School of Dentistry and a spokesperson for the American Dental Association (ADA), told Live Science by email. When these microbes feed off the sugar from those foods, they produce acids that break down tooth enamel, the protective outer covering of the tooth, she said.

Related: How often should you floss?

"Since plaque is sticky, the acids produced by the bacteria in plaque can stay in contact with your teeth for a long time and, over time, break down enamel, creating the perfect environment for a cavity to form," Kumar said. "Cavities usually develop over an extended period of time and take months to years to form." 

This is due to the enamel's hardy structure. Made primarily of a sturdy mineral called calcium phosphate, the tooth's outermost layer is the hardest tissue in the human body, according to a 2017 review published in the journal Physiology Reviews. This allows enamel to shield the underlying dental pulp from damage caused by temperature changes, physical trauma or harmful chemicals. 

Acids produced by plaque bacteria are too weak to deplete enamel of all its minerals at once — however, if they stay in contact with teeth for long enough, the acids will eventually break through the enamel to the sensitive tissues beneath. 

Kumar said that some individuals, particularly those with a condition called dry mouth, are more susceptible than others to tooth decay from plaque and tartar, which is hardened dental plaque that can't be removed with normal brushing and flossing. Saliva not only helps people chew and swallow food but also protects teeth and gums by reducing the growth of harmful bacteria and maintaining a neutral pH in the mouth, according to the ADA. It does this by helping flush microbes and dietary carbs from the mouth and by supplying compounds that slow microbial growth or stop bacteria from sticking to teeth.

Dry mouth can be caused by multiple factors, including cigarette smoking, radiation therapy applied to the head or neck, and certain medications, such as tricyclic antidepressants, decongestants and diuretics, Kumar said.

Children and older adults are also at higher risk of cavities than other age groups. "Poor oral hygiene habits, frequent consumption of sugary diet and frequent snacking are just a few ways children can be more susceptible, but having a family history of cavities can also contribute to this [risk]," Kumar said.

Tooth decay in older adults, on the other hand, is linked to dental fillings. "Because many older adults lacked fluoride and modern dental care when growing up, they often have many dental fillings, and these fillings are weakened over the years and tend to fracture," Kumar said. Bacteria accumulate in these tiny cracks and cause acid buildup, leading to decay, she added.

"You might also be at increased risk if you snack between meals, eat sugary foods and drinks at frequent intervals, and have cracked or chipped teeth," she said.

This article is for informational purposes only and is not meant to offer medical advice.

If you deal with constant breakouts of pimples, you might be tempted to eliminate sugar from your diet. After all, that's the advice offered by various online sources, and numerous studies seem to back it up. But the bittersweet truth is that cutting out sugar likely won't be enough to solve your pimple problem.

This raises a question: Does eating sugar actually cause acne? Because of the interplay between many factors involved in acne, pointing to sweet treats as the sole culprit may be an oversimplified explanation, experts told Live Science.

Acne results from complex interactions among hormone levels, oil glands, clumping skin cells and the skin microbiome, the community of microorganisms on the skin, combined with lifestyle factors like stress and diet, said Dr. Anjali Mahto, a consultant dermatologist and spokesperson for the British Association of Dermatologists.

Due to this ensemble of factors, "dietary changes alone are generally not recommended as the only treatment for patients with acne," Dr. Tanya Greywal, a dermatologist and instructor at the University of Washington, told Live Science in an email. "Many times topical or oral medications are also necessary."

Related: Does dairy cause acne?

Nutritional studies have found a link between sugar intake and acne. Studies from China, France and Turkey tracked participants' diets and spotted correlations between the two. However, those observational studies don't prove that sugar causes acne; other shared factors may underlie the results.

In a randomized, controlled trial in South Korea, participants with acne who were placed on a reduced-carb, low-glycemic diet experienced slight improvements in their acne compared with participants on carb-heavy diets.

However, it's hard to draw definitive conclusions because many acne studies have experimental design flaws that make their results difficult to interpret. For example, participants self-diagnosed with acne may have visually similar, yet distinct skin conditions, like folliculitis. Therefore, studies may include people who don't actually have acne.

In observational studies that explore correlations between diet and acne, participants typically complete surveys about their meals. However, people are "not very good at recording exactly what they've had or the amounts," Mahto told Live Science. Surveys also tend to be taken at a few points in time and, therefore, largely ignore how dietary patterns vary over long periods. To complicate things, sugary foods also often contain other ingredients that possibly influence acne, such as dairy or cocoa.

These limitations raise doubts about the link between sugar and acne. Nevertheless, dieting is a common strategy for managing the condition because "people like to try and control the things that they can," Mahto noted.

Other acne triggers are often unaccounted for in nutritional studies and less easily controlled. For example, a buildup of the stress hormone cortisol can worsen acne, or people may have underlying conditions that provoke acne, such as polycystic ovary syndrome (PCOS), a condition involving insulin resistance and excessive synthesis of male hormones by the ovaries.

Surges in male hormones, like testosterone and its byproduct dihydrotestosterone are the primary triggers for acne in both sexes. High male hormone levels in the skin cause oil-producing glands to churn out more of a moisturizing substance called sebum. Pimples appear when hair follicle pores become clogged with an excess of this oily amalgam. Under these conditions, skin cells become sticky and clump together, adding to the clog. This creates a supportive environment for bacteria, mainly Cutibacterium acnes, some strains of which provoke inflammation, giving zits their signature red, swollen appearance.

Foods that trigger a sudden uptick in blood sugar levels could theoretically boost the production of these acne-causing hormones. High-glycemic foods, like white bread, contain little fiber and release sugar into the blood rapidly, triggering an insulin response. This fuels a spike in insulin growth factor-1, a hormone that promotes male hormone production. Meanwhile, high-fiber foods, like most fruits, are considered low on the glycemic index and release sugar into the bloodstream gradually without triggering an insulin response.

Related: Which fruits are good for diabetics?

Following this theory, sugar may be less likely to trigger acne if it's consumed with fiber. However, although insulin surges can set off acne-triggering hormonal changes, the confounding factors that creep into studies muddy our understanding of how strongly sugar drives breakouts. Overindulging on sugary treats probably does contribute to acne, but it's difficult to weigh its effect against other triggers.

In an effort to treat their acne, people often self-manage their diet in lieu of consulting a dermatologist, and by cutting out sugar and other foods alleged to provoke acne, they could develop worryingly restrictive eating behaviors. And although "eating well for your skin is the same as eating well for every other organ of your body," Mahto said, obsessing over what you eat probably won't cure your acne.

This article is for informational purposes only and is not meant to offer medical advice.

Sugar may disrupt the community of bacteria living in the gut, thereby depleting crucial immune cells and causing obesity down the line, a new mouse study suggests. 

So far, the results have been shown only in mice. But if follow-up studies show similar trends in humans, that could eventually lead to treatments for metabolic disease and obesity, said senior author Ivaylo Ivanov, an associate professor of microbiology and immunology at Columbia University Vagelos College of Physicians and Surgeons. 

In the recent study, published online Aug. 29 in the journal Cell, scientists found that feeding mice a high-sugar diet containing sucrose and maltodextrin caused specific bacteria, called segmented filamentous bacteria (SFB), in the mice's intestines to die due to an overgrowth of different gut bugs. The sudden loss of SFB triggered a chain reaction in the mouse gut that ultimately changed how the animals absorbed dietary fat. 

This, in turn, caused the mice to become obese and develop features of "metabolic syndrome," a cluster of conditions — such as high blood pressure, high blood sugar and insulin resistance — that collectively raise the risk of heart disease, stroke and type 2 diabetes. 

Related: Gut bacteria may 'talk' to the brain, mouse study suggests 

The results suggest that SFB somehow protect against metabolic syndrome and excess weight gain, but how do the gut bugs do it? It turns out that SFB "talk" to the immune system, encouraging the production of a specific type of immune cell called Th17. These immune cells release proteins that affect the lining of the intestine, preventing excess fat from being absorbed through the tissue and into the bloodstream. 

Broadly, SFB can be found in many animals — including rodents, fish and birds — but they haven't been found in humans, Ivanov noted. However, humans do carry a different set of gut bacteria that can induce Th17 cells just like SFB do, and early research hints that these bacteria may be similarly depleted by high-sugar diets, he said. In other words, although humans may not carry SFB, sugar may still exert similar effects on the mouse and human gut microbiomes and immune systems.

"Really what's providing the effect is the T cells — so the bacteria are inducing the T cells, and T cells are providing the effect," Ivanov told Live Science. "We hypothesize that, in humans, inducing these T cells will also be beneficial."

In their recent mouse study, the researchers placed mice on a high-sugar, high-fat diet for a month to see how their gut bugs might change. They found that the diet spurred the growth of a bacterium called Faecalibaculum rodentium, which essentially crowded out the SFB growing in the mouse gut, depleting its numbers. As the mice steadily lost SFB, their overall number of Th17 cells also fell, and they gained weight and developed insulin resistance and glucose intolerance — all signs of metabolic syndrome. 

These effects weren't observed in mice that were fed a low-sugar, low-fat diet, or in mice fed a sugar-free, high-fat diet, but mice fed a high-sugar, low-fat diet also swiftly lost their SFB. This suggests that it was specifically the sugar that was driving the harmful loss of the bacteria and the Th17 cells. 

Basically, the Th17 cells provided an "armor" that protected the mice from developing metabolic disease, and sugar indirectly destroyed that armor by messing with the microbiome, Ivanov explained.

In a different experiment, the team eliminated SFB from a group of mice and then fed them a sugar-free, high-fat diet. They found that these mice also gained weight and developed metabolic disease, despite not having eaten sugar. So what gives? In essence, without the right gut bugs, the mice didn't make enough Th17 cells and they thus lacked that aforementioned armor. The team found that they could provide that armor in two ways: by feeding the mice a probiotic imbued with SFB or by directly injecting Th17 cells into their bodies.

This suggests that, if a mouse's gut has already been depleted of SFB, cutting down on sugar won't help the rodent avoid metabolic disease. If this finding carries over to humans, that suggests that consuming less sugar wouldn't necessarily be helpful if one's gut microbiome is already disrupted. Therefore, an additional intervention might be needed to restore the gut bugs or Th17 cells of those people, Ivanov said.  

Again, more research is needed to know if similar forces are at work in the human gut. Ivanov and his team are also trying to understand how gut bacteria help Th17 cells grow in the mouse gut and whether that mechanism also applies in humans.

"Even after 10 years of studying this, we don't understand completely this process, this mechanism, how exactly the bacteria is inducing these T cells," Ivanov said. "We know a lot, but still there are a lot of questions."

Originally published on Live Science.

Blood sugar, or glucose, is the main source of fuel for our bodies. It powers up our internal organs, muscles and nervous system. Keeping your blood sugar in check is essential to our physical health, wellbeing and energy levels. But what is considered a normal blood glucose level? And what happens when it rises above the normal threshold?  

Our blood sugar levels are directly related to the food we eat. We obtain glucose mostly from carbohydrate-rich foods like bread, pasta, potatoes or fruit, but many different food groups play a role in regulating glucose metabolism. How we absorb, use and store this important sugar is dependent on multiple complex processes that take place in our digestive systems. 

There is no single universal value that would describe a healthy blood sugar level. What constitutes normal blood glucose varies for an individual depending on a range of factors, including age, any underlying medical conditions, and the medications they take. It will also be heavily linked to when you consumed your last meal. Hence when we refer to 'normal blood sugar levels', we refer to a range of values that are considered healthy.

Here, we will discuss everything you need to know about a healthy blood sugar range.

Normal blood sugar before and after meals

Normal blood sugar levels vary from person to person. That's why when we talk about 'normal' blood glucose levels, we refer to a range of values that are considered healthy for most individuals. According to the World Health Organization (WHO), a normal range for fasting blood sugar (the amount of glucose in your blood at least eight hours after a meal) is between 70 and 100 milligrams per deciliter (mg/DL).

For most people, eating a meal or drinking a sugary drink will lead to a temporary increase in the blood glucose levels. As stated by the American Diabetes Association (ADA), the blood sugar two hours after eating should not exceed 140 milligrams per deciliter. However, people with certain metabolic conditions, such as prediabetes or diabetes, typically have lower blood sugar than those guidelines suggest. Researchers from the Journal of Diabetes Science and Technology continuously measured people's blood glucose and found that most individuals averaged around 82 mg/DL during the night and around 93 mg/DL during the day, and spiked to a maximum of 132 mg/DL an hour after a meal. 

Fluctuations in blood glucose levels, both before and after meals, are perfectly normal and reflect how your body absorbs, uses and stores this important sugar at a given point in time. When your food reaches your stomach, your digestive enzymes will break down complex carbohydrate molecules into smaller particles - sugars such as glucose. Glucose is then absorbed by the small intestine and eventually passed into the bloodstream, where it's distributed across the body. In order for the glucose to be shepherded into the cells and utilised, the pancreas needs to release the hormone insulin. 

Our bodies are designed to keep glucose levels constant in the blood. After all the energy needed is delivered to the body's cells, any leftover glucose needs to be stored away. It can't be stored in its original form, it needs to be transformed into a compound called glycogen. Glycogen then is built into the liver and the muscles as a backup source of energy if blood glucose levels fall below optimum levels.

When there isn't enough glucose stored to maintain normal blood-sugar levels, the body can also produce its own glucose from non-carbohydrate sources (such as amino acids and glycerol). This process is known as gluconeogenesis and occurs most often during intense exercise or starvation. It's also common when following low-carb diets, such as keto or Atkins. 

While it may seem complicated (and it is), there's a good reason for our bodies to keep up this never-ending dance with glucose: too much or too little glucose in the blood can lead to serious health problems. 

When there is too much glucose over an extended time (hyperglycemia), it can lead to severe nerve damage, impaired immunity, and heart and kidney disease. 

On the other hand, not enough glucose in the blood over several minutes to hours (hypoglycemia) can negatively affect the functioning of the nervous system. Common symptoms of hypoglycemia include fatigue, fainting, irritability and, in some cases, seizures, coma and death. 

• Related: How do we know when blood oxygen is too low?

Blood sugar targets in people with diabetes

In people with diabetes, blood sugar levels are too high, either because the individual isn't making any insulin (type 1 diabetes), or isn't able to make or use insulin efficiently (type 2 diabetes). As a result, glucose levels then remain elevated in the blood and fuel can't enter cells.

Blood sugar targets for diabetes patients are based on how long the person has had diabetes for, their age, and other underlying medical conditions and lifestyle factors. 

But generally, according to the ADA, for most non-pregnant adults with diabetes the fasting blood sugar target range should be in the range of between 80 and 130 mg/DL. Meanwhile, the ADA suggests the after-meal goal about two hours after eating for the same subset of patients should be less than 180 mg/DL. 

Overall, eating plenty of fruit and vegetables, maintaining a healthy weight, and getting regular physical activity alongside medication can all help stabilize and maintain normal blood sugar levels in people with type 2 diabetes.

For pregnant women who have pre-existing diabetes or develop diabetes during pregnancy, ADA guidelines are generally lower. Fasting glucose targets for this population should be less than 95 mg/DL, while they suggest that the after-meal goal about two hours after eating should be below 120 mg/DL.

• Related: Type 3 diabetes: Symptoms, causes and treatments
• Related: Vegan diet for diabetes: Tips, benefits and safety

What is a normal A1C?

A person's A1C is a measure of their average blood glucose levels over the previous 2 or 3 months, and it is measured through a blood test. A normal result for someone without diabetes or prediabetes would be below 5.7%; an A1C between 5.7% and 6.4% indicates prediabetes; and if your A1C is above 6.4% you would be diagnosed as having diabetes, according to the CDC.

Specifically, the A1C test is a measure of the percent of your red blood cells that have sugar-coated hemoglobin attached to them. The glucose that enters your bloodstream (from carbohydrates that you eat) gets stuck to hemoglobin molecules on red blood cells. And the more glucose in your bloodstream (higher blood sugar levels), the more of your blood's hemoglobin will be "sugar-coated," and the higher your A1C will be, according to the CDC. As such, for people with diabetes (type 1 or 2), the number can give you and your doctors a sense of how well your sugars are being controlled. 

The ADA recommends that most adults with diabetes should keep their A1C below 7% to reduce the risk of diabetes-related complications; the goal is the generally the same for many children with diabetes Targets for the elderly with diabetes are slightly less stringent — for the otherwise healthy with few coexisting chronic illnesses and intact cognitive function, the ADA recommends less than 7.5%, while those who don't meet these requirements have a more lenient goal of below 8.0% to 8.5%. 

According to the Mayo Clinic, higher A1C numbers are linked to a greater risk for diabetes complications, while lower A1Cs have been correlated with a reduced risk of these complications, such as heart disease, kidney disease and vision problems. 

This article is for informational purposes only, and is not meant to offer medical advice.  

This article was updated on Aug. 24, 2022 by Live Science Health Writer Anna Gora.

Additional resources

• Learn more about how high blood sugar levels put you on the road to developing diabetes and heart disease in this explainer by Harvard Health. 
• Read about the risk of high sugar levels and diabetes in pregnant women in this explainer by the Cleveland Clinic. 
• Discover the dangers of low blood sugar, with or without diabetes, in this explainer by the Mayo Clinic.

Bibliography

"The Big Picture: Checking Your Blood Sugar," American Diabetes Association. https://www.diabetes.org/healthy-living/medication-treatments/blood-glucose-testing-and-control/checking-your-blood-sugar

"Mean fasting blood glucose." World Health Organization. https://www.who.int/data/gho/indicator-metadata-registry/imr-details/2380 

"Continuous Glucose Profiles in Healthy Subjects under Everyday Life Conditions and after Different Meals" 2017, Journal of Diabetes Science and Technology https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2769652/ 

"Management of Diabetes in Pregnancy: Standards of Medical Care in Diabetes—2021." ADA. https://diabetesjournals.org/care/article/44/Supplement_1/S200/30761/14-Management-of-Diabetes-in-Pregnancy-Standards  

"Diabetes tests." CDC. https://www.cdc.gov/diabetes/basics/getting-tested.html 

"Understanding A1C." ADA. https://www.diabetes.org/a1c

"Older Adults: Standards of Medical Care in Diabetes—2021." ADA. https://diabetesjournals.org/care/article/44/Supplement_1/S168/30583/12-Older-Adults-Standards-of-Medical-Care-in

"A1C test." Mayo Clinic. https://www.mayoclinic.org/tests-procedures/a1c-test/about/pac-20384643

Originally published on Live Science.

The most common form of diabetes, type 2 diabetes is a chronic disease whose defining factor is high blood sugar, or glucose. 

Glucose is a critical source of energy for the body's cells. When someone eats food, any of the sugars in that food ultimately enters the blood; then, the pancreas releases the hormone insulin, which guides the blood glucose into cells. That step is essential to keeping the body’s cells fueled and also maintaining a healthy level of glucose in the blood.. However, in people with type 2 diabetes, the pancreas doesn't produce enough insulin and/or the body doesn't use that insulin efficiently. 

The result is an elevated level of glucose in the blood, which, over time, can lead to a host of serious complications, including heart disease, kidney disease and eye disease. 

More than 37 million people in the U.S., or roughly 1 in 10, have diabetes, according to the Centers for Disease Control and Prevention (CDC); of those, about 90% to 95% have type 2 diabetes. 

In addition, about 96 million people in the U.S., or about 1 in 3, have prediabetes, in which blood sugar levels are high but not high enough for a person to be diagnosed with type 2 diabetes, per the CDC. This condition puts them at risk for diabetes, heart disease and stroke, but most are unaware they have it.

• Related: Which vegetables are good for diabetics?
• Related: Which fruits are good for diabetics?

Causes

Type 2 diabetes is linked to both genetic and lifestyle factors. Risk factors include having prediabetes, being overweight, engaging in less than 150 minutes of exercise a week and being older than 45, the CDC says. The disease also tends to run in families and occurs more often in African American, Hispanic/Latino American Indian and Alaska Native populations. 

Why these factors raise the risk of the chronic disease is unclear. One possible link, according to the National Institute of Diabetes and Digestive and Kidney Diseases, involves extra weight, particularly around the waist. Extra fat has been linked to insulin resistance, in which the body does not use insulin efficiently to regulate blood sugar. Though researchers aren’t certain the mechanism behind this link, according to the American Diabetes Association, that extra fat could lead to inflammation, physiological stress or other changes in the body’s cells that ultimately cause insulin resistance. Notably, however, type 2 diabetes can also develop in people who are not overweight or obese, mostly in older adults.

Symptoms & complications

Early symptoms of type 2 diabetes include increased thirst, urination and hunger; fatigue; blurred vision; tingling extremities; and slowly healing sores or skin infections, according to the National Library of Medicine. But these symptoms often appear gradually over the course of years and can be so mild that they are missed. Sometimes, there are no symptoms at all. 

Unexplained weight loss can also be a symptom of type 2 diabetes, said Dr. Minisha Sood, an endocrinologist at Northwell Health in New York. This symptom can sometimes be confusing to patients, because diabetes is associated with obesity and too much weight gain. And although this is true, type 2 diabetes can lead to weight loss, mostly through a decrease in "water weight," she said.

"When blood sugar exceeds a certain level … the body has to eliminate that sugar somehow," Sood said. This is done mostly through the kidneys, and the body also gets rid of water along with the sugar. "Patients end up losing a lot of water," she said.

The long-term complications of type 2 diabetes include heart attack, nerve and kidney damage, blindness, erectile dysfunction and dementia, according to the Cleveland Clinic. For instance, having too much glucose in your blood can lead to eye diseases such as diabetic retinopathy, which affects blood vessels in the retina and is the leading cause of blindness in the U.S.; glaucoma, which in the case of diabetes can result from damage to blood vessels in the front of the eye that ultimately causes fluid build-up and damage to the optic nerve; cataracts, which tends to develop more readily in someone with diabetes, possibly due to deposits of glucose in the eyes' lenses, according to Medline Plus.

Although these complications may seem varied, there is a common link. "Glucose can be toxic to blood vessels," Sood said, and damage to blood vessels over time causes some of these serious conditions.

COVID-19, the disease caused by the coronavirus SARS-CoV-2, can also be more serious in individuals with diabetes compared with people who don’t have diabetes. For instance, research published April 23, 2020 in the Journal of Infection, suggested people with diabetes were 3.7 times more likely to have a severe case of COVID-19 or to die from it as compared with individuals with no underlying health conditions. That research was based on a review of 13 relevant studies.  

There is also preliminary research suggesting that COVID-19 can cause both type 1 diabetes and type 2 diabetes. In a study based on information from two health databases, researchers found that individuals younger than 18 were more likely to be diagnosed with diabetes more than 30 days after a COVID-19 infection compared with individuals not infected with the disease, researchers reported online Jan. 14, 2022 in the CDC journal Morbidity and Mortality Weekly Report. Diabetes diagnoses in these COVID-19 patients were 166% and 31% greater compared with non-COVID-19 individuals, respectively for the two databases.

Diagnosis

Some people learn they have type 2 diabetes through routine blood testing — for example, when a doctor checks blood glucose levels during an annual exam, or for diabetes screening, Sood said.

The American Diabetes Association recommends screening for all adults age 45 and older, as well as in the following groups, the Mayo Clinic reported:

• Individuals who are under 45 and who are overweight or have obesity, plus have one or more risk factors tied to diabetes.
• Women who have been diagnosed with gestational diabetes.
• Individuals with a prediabetes diagnosis.
• Kids who are overweight or have obesity, plus have a family history of type 2 diabetes or one or more other risk factors.

Though normal blood sugar levels can vary among individuals, there are certain ranges that are considered "normal." For instance, fasting blood sugar (the amount of glucose in the blood at least eight hours after a meal) is between 70 and 100 milligrams per deciliter (mg/dL), according to the World Health Organization (WHO). Most people's blood glucose levels rise after they eat. According to the American Diabetes Association (ADA), the normal blood sugar range two hours after someone eats is generally less than 140 mg/dL.

According to the ADA, a person can be diagnosed with diabetes if they meet one of these criteria:

• They have a fasting blood glucose level greater than or equal to 126 mg/dL.
• They have a blood glucose level greater than or equal to 200 mg/dL two hours after they drink a special sugar solution.
• They get a result of greater than or equal to 6.5% on an A1C test, which measures average blood sugar for the past three months, roughly.

Given that a family history of type 2 diabetes raises the risk of developing the condition, people who fall into that category should talk to their doctor about being screened, Sood said.

"If it's screened for, and identified early, changes can be implemented that could prevent progression of the disease, and complications," Sood told Live Science.

Treatment

To manage type 2 diabetes, doctors recommend changes to your diet. Eating a healthy including smaller portion sizes; increased intake of high-fiber foods, such as fruits, non-starchy vegetables and whole grains; and fewer calories — and getting regular exercise, the Mayo Clinic says. A keto diet may also be a potential way for diabetics to manage their condition.

Doctors also may prescribe insulin, other injectable medications, or oral diabetes medicines, such as metformin, to address the high blood sugar. Metformin works by both reducing the amount of glucose produced by the liver and increasing the body’s sensitivity to insulin (to become less insulin resistant), according to the diaTribe Foundation. Patients are typically given blood sugar targets and are advised to check their glucose levels periodically.

For people who have obesity and type 2 diabetes and who also have trouble controlling their blood sugars with these treatments, weight loss surgery, also called bariatric surgery, can be a last resort option, according to the National Institute of Diabetes and Digestive and Kidney Diseases. However, the long-term results of this surgery are still being studied.

In 2016, the U.S. Food and Drug Administration approved the use of an "artificial pancreas" that automatically tests blood glucose levels periodically and releases insulin accordingly, Live Science previously reported.  

For people who are diagnosed with type 2 diabetes and have weight issues, Sood recommends they lose at least 5% to 10% of their current body weight. If lifestyle changes don't work well enough to get a person's blood sugar levels under control, then doctors generally prescribe medications to complement those changes, she said.

Is there a cure for type 2 diabetes?

Type 2 diabetes is a progressive disease. New research now suggests that in some cases patients can go into remission, in which their blood sugar levels fall into normal range. Sustained weight loss has proved to be especially successful. 

For instance, in the Diabetes Remission Clinical Trial in the U.K., researchers placed individuals with type 2 diabetes on a calorie-restrictive diet for a year, they reported Oct. 2, 2018 in the journal Cell Metabolism. Out of the 58 patients that stuck with the trial, 69% reached blood glucose levels (measured with the A1C test) that were in the non-diabetic range, meaning they would be classified as “in remission,” after they had lost weight; at the end of the 12 months, 64% showed non-diabetic blood glucose levels, the researchers reported. On average, those who responded to the treatment lost 35.7 pounds (16.2 kilograms). 

• Related: Keto diet vs low carb: what's the difference?
• Related: Type 3 diabetes: Symptoms, causes and treatments

In another study, detailed in 2019 in the journal The Lancet Diabetes & Endocrinology, researchers looked at 300 people in the U.K. with type 2 diabetes. The study is still ongoing, but so far, it's shown encouraging results. In the study, half of the participants stopped taking their diabetes medications and started on a diet replacement formula, after which food was gradually reintroduced; the other half of the participants received standard diabetes care. Two years later, more than a third (36%) of the people with type 2 diabetes who took part in the weight management program were in remission.

However, remission does not mean the diabetes is "cured." That's because blood glucose levels constantly change and if a person were to regain lost weight or revert back to lifestyles that were impacting those levels, their sugars could go back up again to diabetic levels, according to the National Institute of Diabetes and Digestive and Kidney Diseases.

This article is for informational purposes only and is not meant to offer medical advice.

This article was updated on April 11, 2022, by Live Science Contributor Natalie Grover.

Additional resources

• Learn about how having diabetes can affect pregnancy in this explainer from the National Institute of Diabetes and Digestive and Kidney Diseases.
• Check out the latest data on the rising incidence of type 2 diabetes in children and teens in this report by the CDC.
• Learn how blood sugar works and how to achieve blood sugar health in the book "Blood Sugar 101: What They Don't Tell You about Diabetes".

Bibliography

"Type 2 Diabetes," National Institute of Diabetes and Digestive and Kidney Diseases
https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes/type-2-diabetes#diagnose 

"Mean fasting blood glucose," World Health Organization  https://www.who.int/data/gho/indicator-metadata-registry/imr-details/2380 

"Symptoms & Causes of Diabetes," National Institute of Diabetes and Digestive and Kidney Diseases
https://www.niddk.nih.gov/health-information/diabetes/overview/symptoms-causes#type2

"Type 2 Diabetes" Centers for Disease Control and Prevention
https://www.cdc.gov/diabetes/basics/type2.html

"Prediabetes – Your Chance to Prevent Type 2 Diabetes," Centers for Disease Control and Prevention
https://www.cdc.gov/diabetes/basics/prediabetes.html 

"Understanding A1C," American Diabetes Association
https://www.diabetes.org/a1c/diagnosis

"Diabetes: An Overview," Cleveland Clinic
https://my.clevelandclinic.org/health/diseases/7104-diabetes-mellitus-an-overview

"Type 2 diabetes," The Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/type-2-diabetes/diagnosis-treatment/drc-20351199 

"Insulin, Medicines, & Other Diabetes Treatments," National Institute of Diabetes and Digestive and Kidney Disease
https://www.niddk.nih.gov/health-information/diabetes/overview/insulin-medicines-treatments

"Achieving Type 2 Diabetes Remission through Weight Loss," National Institute of Diabetes and Digestive and Kidney Disease
https://www.niddk.nih.gov/health-information/professionals/diabetes-discoveries-practice/achieving-type-2-diabetes-remission-through-weight-loss

"Durability of a primary care-led weight-management intervention for remission of type 2 diabetes: 2-year results of the DiRECT open-label, cluster-randomised trial," 2019 The Lancet
https://www.thelancet.com/journals/landia/article/PIIS2213-8587(19)30068-3/fulltext 

Insulin resistance is a condition in which the hormone insulin, which regulates blood sugar levels, is unable to do its job. 

Under normal circumstances, glucose (or sugar) enters the bloodstream after the body breaks down food that has been consumed. The pancreas secretes insulin to help glucose (the body's main source of energy) enter muscle, fat and liver cells so the glucose can be used for energy or stored for later use. 

But when a person has insulin resistance, this process goes awry.

"Think of insulin as the key that unlocks the door to their cells. That door needs to be opened in order for glucose to exit the blood into the cell," said Kimber Stanhope, a nutrition research scientist at the University of California at Davis. 

When people are insulin resistant, their pancreas is still making those "keys," but they don't work so well to unlock cells and let in glucose, Stanhope said.

Related: What is normal blood sugar?

In the early stages of insulin resistance, cells start to ignore the signal from insulin to take in glucose from the blood. So the pancreas pumps out more insulin to shepherd glucose into cells and blood sugar mostly stays at a normal level. But over time, the cells stop responding even to those higher levels of insulin. 

"It's not like you suddenly don't respond to insulin," said Calum Sutherland, a professor of molecular and cellular diabetes at the University of Dundee in the U.K. "Maybe in the initial stages, you drop 10% of your response, and then after a few months it may drop 30%, and after a few years it may drop 60%. And so, progressively your body loses its ability to respond appropriately to insulin."

Eventually, the pancreas can't keep up, and blood sugar levels rise. 

People with persistently elevated blood sugar are diagnosed with either prediabetes (in which blood sugar levels are high but not high enough to meet the benchmark for diabetes) or type 2 diabetes, which can lead to a host of life-threatening complications if left untreated, according to the CDC. In 2019, about 96 million U.S. adults had prediabetes, according to data from the Centers for Disease Control and Prevention. (CDC)

Causes of insulin resistance

It's not totally clear what causes insulin resistance, according to the American Diabetes Association (ADA).

However, several risk factors have been linked with insulin resistance, including being overweight or obese and having a family history of type 2 diabetes, according to the CDC. 

Some researchers suspect that extra fat tissue may cause inflammation, physiological stress or other changes that contribute to insulin resistance, according to the ADA. 

(Separately, insulin resistance also contributes to weight gain, leading to a vicious cycle.)

Although being overweight is a risk factor for insulin resistance and diabetes, some people with insulin resistance or diabetes are not overweight. In fact, about 10% to 15% of people with type 2 diabetes are at a healthy weight, according to WebMD. 

Inactivity is also a risk factor for insulin resistance, according to the National Diabetes Information Clearinghouse. Inactivity may lead to insulin resistance because muscle tissue uses more glucose than other types of tissue, and muscle becomes better at taking up sugar after exercise. People who exercise infrequently do not benefit from this effect. 

Aging is also tied to insulin resistance, because people typically lose muscle mass as they age, according to a 2021 review article in the journal Comprehensive Physiology. Lower muscle mass means fewer cells that can take in large amounts of glucose.

Symptoms and diagnosis

Most people in the early stages of insulin resistance have no symptoms and no idea that they are on the pathway to disease. And doctors do not diagnose insulin resistance — also referred to as impaired insulin sensitivity —  it is usually only measured in research studies.

"We don't have a threshold where we say someone is insulin resistant," Sutherland told Live Science.

Doctors may instead diagnose a related condition known as metabolic syndrome, which includes high blood sugar, high cholesterol and high blood pressure levels and excess belly fat, according to the National Heart, Lung and Blood Institute. 

Many people only find out about their blood sugar-processing problems when they start showing symptoms of prediabetes and type 2 diabetes, which is a lifelong, progressive condition. These symptoms include increased thirst, hunger and urination, blurred vision, and slow healing of cuts and sores, according to the Cleveland Clinic. 

To diagnose high blood sugar, doctors may order an A1C blood test, which measures a person's average blood glucose over the preceding three months, or the fasting plasma glucose test, which reveals how effectively the body metabolizes glucose after a person has fasted for eight hours.

Doctors may also order tests that help to diagnose other conditions associated with insulin resistance, such as cardiovascular disease and polycystic ovary syndrome (PCOS), which is a hormonal disorder that can affect women of reproductive age, according to the Cleveland Clinic.

Insulin resistance and diet

Insulin resistance is common nowadays in part because of our Western diets, Sutherland told Live Science. (Western diets are typically high in calories, refined grains and ultraprocessed foods and low in fiber.)

Although no single diet has shown to be most effective, certain diets may improve insulin sensitivity. For instance, diets low in simple or processed sugars but high in fiber and complex carbohydrates may be helpful, according to a review study published in 2019 in the journal Advances in Clinical and Experimental Medicine.

The Mediterranean diet — which emphasizes eating vegetables and fruits, nuts, whole grains, fish and extra virgin olive oil— has been shown in several studies to reduce insulin resistance.

And the Dietary Interventions to Stop Hypertension (DASH) diet — which emphasizes vegetables and fruits, low-fat dairy foods and limits sweets, salt and saturated fats — has also been associated with lower insulin resistance, several studies show.

Can insulin resistance be reversed?

In some people, insulin resistance can be reversed, said Richard Mackenzie, a researcher who studies insulin resistance and metabolism at the University of Roehampton in the U.K. 

"We know with weight/fat loss that insulin resistance improves," Mackenzie told Live Science in an email. "We know that gastric bypass surgery [a type of weight loss surgery] can completely reverse insulin resistance in the matter of days."

To aid such weight loss, doctors may recommend eating fewer processed carbohydrates and less unhealthy fat, sugar, red meat and processed starches, according to the Cleveland Clinic. 

The Diabetes Prevention Program, a long-running study funded by the National Institutes of Health, found that for people at high risk of developing diabetes, losing 5% to 7% of their starting weight helped reduce their chances of developing the disease. (Participants in the study lost weight by changing their diet and being more physically active.)

Physical activity — both high-intensity interval training and moderate physical activity — also increases glucose energy usage and improves muscle insulin sensitivity, a clinical trial published in 2020 found.

Some people with insulin resistance may benefit from a drug called metformin, which reduces the amount of glucose the liver makes and prompts the muscles and other tissues to take up more blood sugar. The results of the Diabetes Prevention Program showed that metformin worked best for younger adults, people with obesity and people with a history of gestational diabetes. 

This article is for informational purposes only and is not meant to offer medical advice.

This article was updated on Feb. 8, 2022, by Live Science contributor Natalie Grover.

Additional resources

• Check out this report by Yale on the latest research linking insulin resistance to fatty liver disease.
• Learn more about metformin in this review published by the Mayo Clinic.

Bibliography

American Diabetes Association. Understanding insulin resistance. https://www.diabetes.org/healthy-living/medication-treatments/insulin-resistance

Centers for Disease Control and Prevention. Insulin resistance and diabetes.
https://www.cdc.gov/diabetes/basics/insulin-resistance.html

Cleveland Clinic. Insulin resistance. https://my.clevelandclinic.org/health/diseases/22206-insulin-resistance

National Institute of Diabetes and Digestive and Kidney Diseases. Diabetes Prevention Program (DPP). U.S. Department of Health and Human Services, National Institutes of Health. https://www.niddk.nih.gov/about-niddk/research-areas/diabetes/diabetes-prevention-program-dpp 

National Institute of Diabetes and Digestive and Kidney Diseases.Insulin resistance & prediabetes. U.S. Department of Health and Human Services, National Institutes of Health.https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes/prediabetes-insulin-resistance#:~:text=Insulin%20resistance%20is%20when%20cells,help%20glucose%20enter%20your%20cells

Additional reporting by Amanda Chan, Live Science contributor

Follow Tia Ghose on Twitter and Google+. Follow LiveScience @livescience, Facebook & Google+.

Carbohydrates are the sugars, starches and fibers found in fruits, grains, vegetables and milk products, according to the UK’s National Health Service (NHS). Though often maligned in trendy diets, carbohydrates — one of the basic food groups — are important to a healthy diet.

"Carbohydrates are macronutrients, meaning they are one of the three main ways the body obtains energy, or calories," said Paige Smathers, a Utah-based registered dietitian. The American Diabetes Association notes that carbohydrates are the body's main source of energy. They are called carbohydrates because, at the chemical level, they contain carbon, hydrogen and oxygen.

There are three macronutrients: carbohydrates, protein and fats, Smathers said. Macronutrients are essential for proper body functioning, and the body requires large amounts of them. All macronutrients must be obtained through diet; the body cannot produce macronutrients on its own.

Related: Digestive system: facts, function & diseases

The recommended daily amount (RDA) of carbs for adults is around 4.7 ounces (135 grams), according to the National Institutes of Health (NIH); however, the NIH also recommends that everyone should have his or her own carbohydrate goal. Carb intake for most people should be between 45% and 65% of total calories. One gram of carbohydrates equals about 4 calories, so a diet of 1,800 calories per day would equal about 202 grams on the low end and 292 grams of carbs on the high end. However, people with diabetes should not eat more than 200 grams of carbs per day, while pregnant women need at least 175 grams, according to the NIH.

Why are carbohydrates important?

Carbohydrates provide fuel for the central nervous system and energy for working muscles. They also prevent protein from being used as an energy source and enable fat metabolism, according to the NHS.

Also, "carbohydrates are important for brain function," Smathers said. They are an influence on "mood, memory, etc., as well as a quick energy source." In fact, the RDA of carbohydrates is based on the amount of carbs the brain needs to function.

Two 2017 studies published in the journal Proceedings of the National Academy of Sciences have also linked carbs to decision-making. In the studies, people who ate a high-carbohydrate breakfast were less willing to share when playing the "ultimatum game" than those who ate high-protein breakfasts. Scientists speculate this may be caused by baseline dopamine levels, which are higher after eating carbohydrates. This doesn't mean carbs make you mean, but underscores how different types of food intake can affect cognition and behavior. 

Simple vs. complex carbohydrates

Carbohydrates are classified as simple or complex, Smathers said. The difference between the two forms is the chemical structure and how quickly the sugar is absorbed and digested. Generally speaking, simple carbs are digested and absorbed more quickly and easily than complex carbs, according to the NIH.

Simple carbohydrates contain just one or two sugars, such as fructose (found in fruits) and galactose (found in milk products). These single sugars are called monosaccharides. Carbs with two sugars — such as sucrose (table sugar), lactose (from dairy) and maltose (found in beer and some vegetables) — are called disaccharides, according to the NIH.

Simple carbs are also in candy, soda and syrups. However, these foods are made with processed and refined sugars and do not have vitamins, minerals or fiber. They are called "empty calories" and can lead to weight gain, according to the NIH.

Complex carbohydrates (polysaccharides) have three or more sugars. They are often referred to as starchy foods and include beans, peas, lentils, peanuts, potatoes, corn, parsnips, whole-grain breads and cereals.

Smathers pointed out that, while all carbohydrates function as relatively quick energy sources, simple carbs cause bursts of energy much more quickly than complex carbs because of the quicker rate at which they are digested and absorbed. Simple carbs can lead to spikes in blood sugar levels and sugar highs, while complex carbs provide more sustained energy.

Smathers offered the following advice: "It's best to focus on getting primarily complex carbs in your diet, including whole grains and vegetables."

What are the different types of carbohydrates?

In the body, carbs break down into smaller units of sugar, such as glucose and fructose, according to the American Heart Association. The small intestine absorbs these smaller units, which then enter the bloodstream and travel to the liver. The liver converts all of these sugars into glucose, which is carried through the bloodstream — accompanied by insulin — and converted into energy for basic body functioning and physical activity, according to the journal Nutrients.

If the glucose is not immediately needed for energy, the body can store up to 2,000 calories of it in the liver and skeletal muscles in the form of glycogen, according to the University of Nebraska. Once glycogen stores are full, carbs are stored as fat. If you have insufficient carbohydrate intake or stores, the body will consume protein for fuel. This is problematic because the body needs protein to make muscles. Using protein instead of carbohydrates for fuel also puts stress on the kidneys, leading to the passage of painful byproducts in the urine.

Fiber is essential to digestion. Fibers promote healthy bowel movements and decrease the risk of chronic diseases such as coronary heart disease and diabetes, according to Harvard Medical School. However, unlike sugars and starches, fibers are not absorbed in the small intestine and are not converted to glucose. Instead, they pass into the large intestine relatively intact, where they are converted to hydrogen and carbon dioxide and fatty acids. - The NHS recommends that people consume up to 30 grams of fiber per day as part of a balanced diet. Sources of fiber include fruits, grains and vegetables, especially legumes.

Related: Gestational diabetes: Symptoms, diagnosis & complications

Smathers pointed out that carbs are also found naturally in some forms of dairy and both starchy and non-starchy vegetables. For example, non-starchy vegetables like lettuces, kale, green beans, celery, carrots and broccoli all contain carbs. Starchy vegetables like potatoes and corn also contain carbohydrates, but in larger amounts. According to the American Diabetes Association, non-starchy vegetables generally contain only about 5 grams of carbohydrates per cup of raw vegetables, and most of those carbs come from fiber.

What’s the difference between good and bad carbohydrates?

Carbohydrates are found in foods you know are good for you (vegetables) and ones you know are not (doughnuts). This has led to the idea that some carbs are "good" and some are "bad." As Live Science has previously reported, carbs commonly considered bad include pastries, sodas, highly processed foods, white rice, white bread and other white-flour foods. These are foods with simple carbs. Bad carbs rarely have any nutritional value.

Carbs usually considered good are complex carbs, such as whole grains, fruits, vegetables, beans and legumes. These are not only processed more slowly, but they also contain a bounty of other nutrients.

The Pritikin Longevity Center offers this checklist for determining if a carbohydrate is "good" or "bad."

Good carbs are:

• Low or moderate in calories
• High in nutrients
• Devoid of refined sugars and refined grains
• High in naturally occurring fiber
• Low in sodium
• Low in saturated fat
• Very low in, or devoid of, cholesterol and trans fats

Bad carbs are:

• High in calories
• Full of refined sugars, like corn syrup, white sugar, honey and fruit juices
• High in refined grains like white flour
• Low in many nutrients
• Low in fiber
• High in sodium
• Sometimes high in saturated fat
• Sometimes high in cholesterol and trans fats

Glycemic index

Recently, nutritionists have said that it's not the type of carbohydrate, but rather the carb's glycemic index that's important. The glycemic index measures how quickly and how much a carbohydrate raises blood sugar.

High-glycemic foods like pastries raise blood sugar highly and rapidly; low-glycemic foods raise it gently and to a lesser degree. Some research has linked high-glycemic foods with diabetes, obesity, heart disease and certain cancers, according to Harvard Medical School. 

A global study published in the New England Journal of Medicine, found that poor-quality carbohydrates (high-glycemic diet) lead to higher risks of heart attacks and strokes. In total 137,851 people were surveyed to establish their glycemic index and the glycemic load (amount of carbs multiplied by its glycemic index) of their diets. The results of the study found that the participants who were placed in the top 20% of all recorded glycemic index, were 50% more likely to have a cardiovascular attack or stroke if they had a pre-existing heart condition. Those without a pre-existing condition increased their risk by 20%. During the studies follow-up period, there were 8,780 deaths and 8,252 participants had at least one major cardiovascular event.  

On the other hand, recent research suggests that following a low-glycemic diet may not actually be helpful. A 2014 study published in JAMA found that overweight adults eating a balanced diet did not see much additional improvement on a low-calorie, low-glycemic index diet. Scientists measured insulin sensitivity, systolic blood pressure, LDL cholesterol and HDL cholesterol and saw that the low-glycemic diet did not improve them. It did however, lower triglycerides - a type of fat that can be found in the blood and in high quantities - increases the risk of heart disease, according to the cholesterol charity Heart UK. 

Carbohydrate benefits

What are the benefits of carbohydrates?

The right kind of carbs can be incredibly good for you. Not only are they necessary for your health, but they carry a variety of added benefits.

Mental health

Carbohydrates may be important to mental health. A study published in 2009 in the journal JAMA Internal Medicine found that people on a high-fat, low-carb diet for a year had more anxiety, depression and anger than people on a low-fat, high-carb diet. Scientists suspect that carbohydrates help with the production of serotonin in the brain.

Carbs may help memory, too. A 2008 study at Tufts University had overweight women cut carbs entirely from their diets for one week. Then, they tested the women's cognitive skills, visual attention and spatial memory. The women on no-carb diets did worse than overweight women on low-calorie diets that contained a healthy amount of carbohydrates.

Weight loss

Though carbs are often blamed for weight gain, the right kind of carbs can actually help you lose and maintain a healthy weight. This happens because many good carbohydrates, especially whole grains and vegetables with skin, contain fiber, according to the NHS. 

A study published in the Journal of Nutrition in 2009 followed middle-age women for 20 months and found that participants who ate more fiber lost weight, while those who decreased their fiber intake gained weight. Another recent study linked fat loss with low-fat diets, not low-carb ones.

While some studies have found that low-carb diets do help people lose weight, a meta analysis conducted in 2015 and published in The Lancet found that when viewed long term, low-fat and low-carb diets had similar success rates. People lost more weight early on while on low-carb diets but after a year they were all in similar places.

Good source of nutrients

Whole, unprocessed fruits and vegetables are well known for their nutrient content. Some are even considered superfoods because of it — and all of these leafy greens, bright sweet potatoes, juicy berries, tangy citruses and crunchy apples contain carbs.

One important, plentiful source of good carbs is whole grains. A large study published in 2010 in the Journal of the American Dietetic Association found that those eating the most whole grains had significantly higher amounts of fiber, energy and polyunsaturated fats, as well as all micronutrients (except vitamin B12 and sodium). An additional study, published in 2014 in the journal Critical Reviews in Food Science and Nutrition, found that whole grains contain antioxidants, which were previously thought to exist almost exclusively in fruits and vegetables.

Heart health

Fiber also helps to lower cholesterol, said Kelly Toups, a registered dietitian with the Whole Grains Council. The digestive process requires bile acids, which are made partly with cholesterol. As your digestion improves, the liver pulls cholesterol from the blood to create more bile acid, thereby reducing the amount of LDL, the "bad" cholesterol.

Toups referenced a study in the American Journal of Clinical Nutrition that looked at the effect of whole grains on patients taking cholesterol-lowering medications called statins. Those who ate more than 16 grams of whole grains daily had lower bad-cholesterol levels than those who took the statins without eating the whole grains.

Carbohydrate deficiency

Not getting enough carbs can cause problems. Without sufficient fuel, the body gets no energy. Additionally, without sufficient glucose, the central nervous system suffers, which may cause dizziness or mental and physical weakness, according to the NHS. A deficiency of glucose, or low blood sugar, is called hypoglycemia.

If the body has insufficient carbohydrate intake or stores, it will consume protein for fuel. This is problematic because the body needs protein to make muscles. Using protein for fuel instead of carbohydrates also puts stress on the kidneys, leading to the passage of painful byproducts in the urine, according to the University of Cincinnati.

People who don't consume enough carbohydrates may also suffer from insufficient fiber, which can cause digestive problems and constipation.

Additional resources

• American Diabetes Association: Understanding Carbohydrates
• Eat, Drink, and Be Healthy: The Harvard Medical School Guide to Healthy Eating
• Human Metabolism: A Regulatory Perspective

Artificial sweeteners are everywhere, but the jury is still out on whether these chemicals are harmless. Also called non-nutritive sweeteners, these can be synthetic — such as saccharin and aspartame — or naturally derived, such as steviol, which comes from the Stevia plant. To date, the U.S. Food and Drug Administration has approved six types of artificial and two types of natural non-nutritive sweeteners for use in food.

That's been great news for those working hard to curb their sugar consumption. Aspartame, for example, is found in more than 6,000 foods worldwide, and about 5,000-5,500 tons are consumed every year in the United States alone.

The American Diabetes Association — the most well-respected professional group focusing on diabetes — officially recommends diet soda as an alternative to sugar-sweetened beverages. To date, seven U.S. municipalities have imposed a sugary beverage tax to discourage consumption.

However, recent medical studies suggest that policymakers eager to implement a soda tax may also want to include diet drinks because these sweeteners may be contributing to chronic diabetes and cardiovascular diseases as well.

Why are these sweeteners calorie-free?

The key to these virtually calorie-free sweeteners is that they are not broken down during digestion into natural sugars like glucose, fructose and galactose, which are then either used for energy or converted into fat.

Non-nutritive sweeteners have different byproducts that are not converted into calories. Aspartame, for example, undergoes a different metabolic process that doesn’t yield simple sugars. Others such as saccharin and sucralose are not broken down at all, but instead are absorbed directly into the bloodstream and excreted in the urine.

Theoretically, these sweeteners should be a "better" choice than sugar for diabetics. Glucose stimulates release of insulin, a hormone that regulates blood sugar levels. Type 2 diabetes occurs when the body no longer responds as well to insulin as it should, leading to higher levels of glucose in the blood that damages the nerves, kidneys, blood vessels and heart. Since non-nutritive sweeteners aren’t actually sugar, they should sidestep this problem.

Artificial sweeteners, your brain and your microbiome

However, there is growing evidence over the last decade that these sweeteners can alter healthy metabolic processes in other ways, specifically in the gut.

Long-term use of these sweeteners has been associated with a higher risk of Type 2 diabetes. Sweeteners, such as saccharin, have been shown to change the type and function of the gut microbiome, the community of microorganisms that live in the intestine. Aspartame decreases the activity of a gut enzyme that is normally protective against Type 2 diabetes. Furthermore, this response may be exacerbated by the "mismatch" between the body perceiving something as tasting sweet and the expected associated calories. The greater the discrepancy between the sweetness and actual caloric content, the greater the metabolic dysregulation.

Sweeteners have also been shown to change brain activity associated with eating sweet foods. A functional MRI exam, which studies brain activity by measuring blood flow, has shown that sucralose, compared to regular sugar, decreases activity in the amygdala, a part of the brain involved with taste perception and the experience of eating.

Another study revealed that longer-term and higher diet soda consumption are linked to lower activity in the brain's "caudate head," a region that mediates the reward pathway and is necessary for generating a feeling of satisfaction. Researchers have hypothesized that this decreased activity could lead a diet soda drinker to compensate for the lack of pleasure they now derive from the food by increasing their consumption of all foods, not just soda.

Together these cellular and brain studies may explain why people who consume sweeteners still have a higher risk of obesity than individuals who don't consume these products.

As this debate on the pros and cons of these sugar substitutes rages on, we must view these behavioral studies with a grain of salt (or sugar) because many diet soda drinkers — or any health-conscious individual who consumes zero-calorie sweeteners — already has the risk factors for obesity, diabetes, hypertension or heart disease. Those who are already overweight or obese may turn toward low-calorie drinks, making it look as though the diet sodas are causing their weight gain.

This same group may also be less likely to moderate their consumption. For example, those people may think that having a diet soda multiple times a week is much healthier than drinking one case of soda with sugar.

These findings signal that consumers and health practitioners all need to check our assumptions about the health benefits of these products. Sweeteners are everywhere, from beverages to salad dressing, from cookies to yogurt, and we must recognize that there is no guarantee that these chemicals won't increase the burden of metabolic diseases in the future.

As a physician of internal medicine specializing in general prevention and public health, I would like to be able to tell my patients what the true risks and benefits are if they drink diet soda instead of water.

Legislators considering soda taxes to encourage better dietary habits perhaps should think about including foods with non-nutritive sweeteners. Of course, there is an argument to be made for being realistic and pursuing the lesser of two evils. But even if the negative consequences of sugar substitutes doesn't sway our tax policy — for now — at least the medical community should be honest with the public about what they stand to lose or gain, consuming these foods.

• Related: Is diet coke bad for you?

This article was originally published at The Conversation. The publication contributed the article to Live Science's Expert Voices: Op-Ed & Insights.

We love sweet treats. But too much sugar in our diets can lead to weight gain and obesity, Type 2 diabetes and dental decay. We know we shouldn't be eating candy, ice cream, cookies, cakes and drinking sugary sodas, but sometimes they are so hard to resist.

It's as if our brain is hardwired to want these foods.

As a neuroscientist my research centers on how modern day "obesogenic," or obesity-promoting, diets change the brain. I want to understand how what we eat alters our behavior and whether brain changes can be mitigated by other lifestyle factors.

Your body runs on sugar — glucose to be precise. Glucose comes from the Greek word glukos which means sweet. Glucose fuels the cells that make up our body — including brain cells (neurons).

Dopamine "hits" from eating sugar

On an evolutionary basis, our primitive ancestors were scavengers. Sugary foods are excellent sources of energy, so we have evolved to find sweet foods particularly pleasurable. Foods with unpleasant, bitter and sour tastes can be unripe, poisonous or rotting — causing sickness.

So to maximize our survival as a species, we have an innate brain system that makes us like sweet foods since they're a great source of energy to fuel our bodies.

Read more: Forget toast and oatmeal, low-carb breakfasts reduce sugar spikes in those with Type 2 diabetes

When we eat sweet foods the brain's reward system — called the mesolimbic dopamine system — gets activated. Dopamine is a brain chemical released by neurons and can signal that an event was positive. When the reward system fires, it reinforces behaviors — making it more likely for us to carry out these actions again.

Dopamine "hits" from eating sugar promote rapid learning to preferentially find more of these foods.

Our environment today is abundant with sweet, energy rich foods. We no longer have to forage for these special sugary foods — they are available everywhere. Unfortunately, our brain is still functionally very similar to our ancestors, and it really likes sugar. So what happens in the brain when we excessively consume sugar?

Can sugar rewire the brain?

The brain continuously remodels and rewires itself through a process called neuroplasticity. This rewiring can happen in the reward system. Repeated activation of the reward pathway by drugs or by eating lots of sugary foods causes the brain to adapt to frequent stimulation, leading to a sort of tolerance.

In the case of sweet foods, this means we need to eat more to get the same rewarding feeling — a classic feature of addiction.

Food addiction is a controversial subject among scientists and clinicians. While it is true that you can become physically dependent on certain drugs, it is debated whether you can be addicted to food when you need it for basic survival.

The brain wants sugar, then more sugar

Regardless of our need for food to power our bodies, many people experience food cravings, particularly when stressed, hungry or just faced with an alluring display of cakes in a coffee shop.

To resist cravings, we need to inhibit our natural response to indulge in these tasty foods. A network of inhibitory neurons is critical for controlling behavior. These neurons are concentrated in the prefrontal cortex — a key area of the brain involved in decision-making, impulse control and delaying gratification.

Inhibitory neurons are like the brain's brakes and release the chemical GABA. Research in rats has shown that eating high-sugar diets can alter the inhibitory neurons. The sugar-fed rats were also less able to control their behavior and make decisions.

Importantly, this shows that what we eat can influence our ability to resist temptations and may underlie why diet changes are so difficult for people.

A recent study asked people to rate how much they wanted to eat high-calorie snack foods when they were feeling hungry versus when they had recently eaten. The people who regularly ate a high-fat, high-sugar diet rated their cravings for snack foods higher even when they weren't hungry.

This suggests that regularly eating high-sugar foods could amplify cravings — creating a vicious circle of wanting more and more of these foods.

Sugar can disrupt memory formation

Another brain area affected by high sugar diets is the hippocampus — a key memory center.

Research shows that rats eating high-sugar diets were less able to remember whether they had previously seen objects in specific locations before.

The sugar-induced changes in the hippocampus were both a reduction of newborn neurons, which are vital for encoding memories, and an increase in chemicals linked to inflammation.

How to protect your brain from sugar?

The World Health Organization advises that we limit our intake of added sugars to five per cent of our daily calorie intake, which is 25g (six teaspoons).

Considering the average Canadian adult consumes 85g (20 teaspoons) of sugar per day, this is a big diet change for many.

Importantly, the brain's neuroplasticity capabilities allow it to reset to an extent following cutting down on dietary sugar, and physical exercise can augment this process. Foods rich in omega-3 fats (found in fish oil, nuts and seeds) are also neuroprotective and can boost brain chemicals needed to form new neurons.

Read more: Young adults need to eat more omega-3 fats

While it's not easy to break habits like always eating dessert or making your coffee a double-double, your brain will thank you for making positive steps.

The first step is often the hardest. These diet changes can often get easier along the way.

[ Like what you've read? Want more? Sign up for The Conversation's daily newsletter. ]

This article was originally published at The Conversation. The publication contributed the article to Live Science's Expert Voices: Op-Ed & Insights.

Young adults with depression may help reduce their symptoms by eating a healthier diet high in fruits and vegetables, rather than one heavy in sugar-laden, processed foods, according to a preliminary study.

But not everyone is convinced that a healthy diet can act as a full-fledged depression treatment. 

Indeed, one expert told Live Science that, based on the new research, which was published today (Oct. 9) in the journal PLOS ONE, scientists still can't say whether eating fruits and vegetables helps improve depressive symptoms any more than a"dummy pill," or a placebo intended to do nothing at all.

The link between diet and depression

Studies have long linked healthy diets, particularly those rich in fruits, vegetables, fish and whole grains, with a reduced risk of depression, according to a 2013 review in The American Journal of Clinical Nutrition.

However, although existing data suggest that there's some connection between poor dietary habits and depression, it's unclear whether there is a "cause-effect" relationship between the two, said Ana Ojeda, a licensed clinical psychologist at Nicklaus Children’s Hospital in Miami, who was not involved in the new study. In other words, past research offers no evidence that healthy eating can reverse depressive symptoms. 

To supply this evidence, scientists need to test dietary habits as they would antidepressant medications — by conducting randomized controlled trials, in which each participant is randomly selected to either receive a treatment or not. The latter group acts as a point of comparison, or control, to see how the treatment group changes throughout the trial.

Related: 8 Tips for Parents of Teens with Depression

To date, only one randomized controlled trial has looked at whether patients diagnosed with depression can find symptom relief through healthy eating, according to a 2019 review in the journal Psychosomatic Medicine. The study, known as the SMILES trial, found that adults who followed a recommended Mediterranean diet for 12 weeks scored better on a depression rating scale than participants who received social support for the same time period.

On average, participants in the SMILES trial were about 40 years old. "What was of interest in our [new] study was whether the findings in older adults could also apply to young adults who were otherwise healthy and of normal body weight," Heather Francis, co-author of the new PLOS ONE study and a clinical neuropsychologist and nutritional neuroscience researcher at Macquarie University in Sydney, told Live Science in an email.

Healthy and happy

Francis and her colleagues recruited 76 adults ages 17 to 35 who all consumed diets high in processed foods, saturated fats and refined sugars. The participants, who also scored "moderate to high" on a scale of depression symptoms used by doctors, were randomly split into two groups. One group received pointers to help improve their dietary habits, a small hamper of pantry items and money for grocery shopping. This "diet group" received two calls from the researchers during the three-week study, to check on their progress.

The control group participants received no food, money or nutritional guidance, and were asked to come back only when the trial concluded.

Following the three-week intervention, the diet group's depression ratings fell within normal range and the participants demonstrated significant improvements in their moods. Scores of those in the control group remained stable. Three months after the study ended, the researchers followed up with 33 of the diet-change participants and found that their moods had remained elevated — at least among the seven of them that had maintained healthy eating habits.  

Related: 7 Ways Depression Differs in Men and Women

The results suggest that "adherence to healthier foods for a period of time has a direct and positive impact on depressive symptoms," Ojeda said.

"These findings add to a growing literature to suggest that healthy diet can be recommended as an effective therapy to improve depression symptoms, as an adjunct to pharmacological and psychological therapy," Francis said. The benefit may stem from a reduction in harmful inflammation, she added — an elevated immune response that can take hold of body tissues as a result of poor dietary habits and is associated with a higher risk of depressive symptoms.

Holes in the research 

Ojeda was impressed by the study's "optimistic results" but notes that the study may  represent only a select subset of patients with depression. 

"Does this diet intervention reduce depression, generally, or only in teens with easy temperaments that can adhere to the plan?" she said. "We may find that kids with [more complex cases]...will not receive the same effect by modifying diet."  

Marc Molendijk, a clinical neuropsychologist at Leiden University in the Netherlands who was not involved in the study, found additional flaws in the work. 

Molendijk noted that the study didn't have an "active control," or a control group that received a different but potentially effective intervention (such as increased social support.)  "They just have a control group with which they do nothing," Molendijk said. Beyond changing what they ate, the diet group received monetary compensation and special attention from the researchers, while the control got nothing, he explained. These extraneous factors may have skewed the final results; there's no way to isolate the true effect of the dietary changes. 

The authors acknowledged this flaw in their design, saying in the paper that "there are difficulties in determining an appropriate active control." However, they assert that the shifts in depression ratings still suggest that "it was the change in diet per se that resulted in improved depression."

But was the improvement that impressive? Molendijk doesn't think so.  

"The effect of a placebo pill [seen in previous studies] is larger than the effect of the diet that these authors report on," he said. 

Related: Mediterranean Diet: Foods, Benefits & Risks

In clinical trials for antidepressant medications, participants often show significant symptom reduction in response to an inert placebo pill, sometimes experiencing up to 30 to 40 % improvement, according to a 2018 review in the journal Frontiers in Psychiatry. In practical terms, that means 8 out of 9 patients may experience equal symptom reduction from either a dummy pill or a true antidepressant drug, according to the review. Molendijk argues that the modest effect of the diet intervention does not exceed what would be expected of a placebo in any given antidepressant trial.    

Previously, Molendijk and his colleagues offered similar critiques of the SMILES trial, pointing out that during the recruitment process participants appeared to be told of the aspirational goals of the study and likely biased the final results.

"I would like to really make explicit that it, of course, would be fantastic if you could cure an illness like depression with diet," Molendijk said. It cannot hurt to eat healthy, he said, but people with depression shouldn't expect to be cured by leafy greens and whole grains because the intervention is "not scientifically proven." What's more, people with depression may blame themselves for not maintaining a healthier diet to begin with and thus worsen their already compromised mental health, he added.

"So far...for me, there's no convincing evidence at all," he said.

• 7 Ways to Recognize Depression in 20-Somethings 
• 9 Celebrities Who Spoke Up about Depression 
• 8 Tips for Dealing with a Depressed Spouse 

Originally published on Live Science. 

High-fructose corn syrup may fuel colon cancer growth, at least in mice, a new study finds.

In the study, published yesterday (March 21) in the journal Science, researchers found that consuming the equivalent of 12 ounces of a beverage sweetened with high-fructose corn syrup accelerated tumor growth in mice that were predisposed to colon cancer.

Still, because the study was done in mice, more research is needed to see if the findings apply to humans. But "our findings in animal models suggest that chronic consumption of sugary drinks can shorten the time it takes [colon] cancer to develop," study co-senior author Dr. Jihye Yun, an assistant professor of molecular and human genetics at Baylor College of Medicine in Houston, said in a statement. Yun conducted the work as a postdoctoral fellow at Weill Cornell Medicine in New York City.

The researchers noted that there's been a rise in colorectal cancer rates among young people in recent decades — during the same time that consumption of sugar-sweetened beverages has increased. If the new results prove true for humans as well, the findings might help explain this link. [7 Odd Things That Raise Your Risk of Cancer (and 1 That Doesn't)]

The study also suggests potential ways to reverse the tumor-promoting effects of high-fructose corn syrup, the authors said.

Bigger tumors

Previous studies in people have linked consumption of sugary drinks with obesity, and obesity in turn is linked with an increased risk of developing colon cancer. But whether sugar itself could promote tumor growth was unclear.

To examine this question, the researchers turned to a mouse model for colon cancer. In these mice, a gene called APC is deleted, which predisposes them to developing polyps, the early stages of colon cancer. This model is similar to what happens in humans — more than 90 percent of people with colorectal cancer also have mutations in the APC gene, the authors said.

When these mice were given water sweetened with high-fructose corn syrup, they developed colon tumors that were larger and more advanced than mice who were given just water. The tumor-enhancing effect of high-fructose corn syrup was seen even in mice that weren't obese.

Lead study author Dr. Marcus Goncalves, an assistant professor of medicine at Weill Cornell Medicine, noted in the statement that the study didn't "show that giving high-fructose syrup causes new tumors, because these mice develop tumors even on normal diets free of added sugar … But when you give them this additional sugar, the tumors grow much bigger."

And the mice didn't have to consume large amounts of high-fructose corn syrup to develop larger tumors — this effect was seen when the mice consumed the equivalent of one can of soda (12 ounces) a day.

The researchers also found that the mouse tumors readily took in both glucose and fructose. Within the tumors, an enzyme known as KHK (ketohexokinase) changed fructose into a compound called fructose-1-phosphate, which promotes the production of fats necessary for tumor growth; and also makes it easier for the tumors to use glucose for energy.

The findings suggest that drugs that target KHK in tumor cells may reverse the tumor-enhancing effects of high-fructose corn syrup, the authors said.

But what about sweeteners besides high-fructose corn syrup? Preliminary experiments suggest that added table sugar has the same effect in these mice, the authors said.

Sugar and cancer

Dr. Patrick Boland, an assistant professor of oncology and gastrointestinal oncologist at Roswell Park Comprehensive Cancer Center in Buffalo, New York, who was not involved with the study, noted that previous research has found a link between consumption of "high glycemic" foods and sugar-sweetened beverages and higher rates of colon cancer recurrence and death. (High glycemic foods, including high-fructose corn syrup, release sugar quickly into the bloodstream.)

"This study provides some potential explanation as to why large amounts of high-fructose corn syrup may not be good for our health in general and specifically as it relates to colon cancer," Boland told Live Science. "We already have data suggesting individuals with colon cancer or those at risk should probably limit the number of sugary drinks they have as much as possible," and the new study supports this, he said.

Still, the findings aren't definitive. "I don't think we have hard proof to say that all sugar should be avoided or that [high-fructose corn syrup] should never be consumed," Boland said. "Many things we see in mice aren't seen in humans."

Additional research looking at the effect of sugary drinks on colon cancer in people would be helpful, he said.

• 10 Do's and Don'ts to Reduce Your Risk of Cancer
• 11 Ways Processed Food Is Different from Real Food
• 9 Disgusting Things That the FDA Allows in Your Food

Originally published on Live Science.

Soda and other sugary beverages aren't exactly known for being healthy. But now, a new study finds that sugar-sweetened beverages are tied to an increased risk of early death.

In the study, published today (March 18) in the journal Circulation, researchers analyzed information from more than 80,000 women and 37,000 men in the health profession who were followed for about three decades. Participants filled out surveys about their diet every four years, and also answered questions about their lifestyle and overall health every two years.

The more sugary beverages people drank — including soft drinks, fruit drinks, energy drinks and sports drinks — the greater their risk of death was during the study period.

For example, those who drank two to six sugar-sweetened beverages (SSBs) per week were 6 percent more likely to die during the study period, compared with those who drank less than one SSB per month. Those who drank one to two SSBs per day were 14 percent more likely to die during the study period compared with those who drank less than one SSB per month. [11 Ways Processed Food Is Different from Real Food]

The findings held even after the researchers took into account factors that could affect people's risk of premature death and disease, such as smoking, alcohol use, physical activity, and consumption of fruits, vegetables and red meat.

"Our results provide further support to limit intake of SSBs and to replace them with other beverages, preferably water, to improve overall health and longevity," study lead author Vasanti Malik, a research scientist at the Harvard T.H. Chan School of Public Health's Department of Nutrition, said in a statement.

It's important to note that the study found only an association and cannot prove that drinking soda or other sugary drinks causes early death.

Added sugar

Sugar-sweetened beverages are the largest source of added sugar in the U.S. diet. While SSB consumption had been dropping in the U.S. over the past decade, in recent years, there's been an increase in consumption among U.S. adults. Consumption of SSBs is also rising in developing countries.

Previous studies have linked SSB intake with weight gain and an increased risk of type 2 diabetes, heart disease and stroke. However, few studies have examined the link between SSB consumption and early death, the researchers said.

In the new study, SSB consumption was particularly strongly linked with an increased risk of death from heart disease. Those who consumed two or more SSBs per day had a 31-percent higher risk of early death from heart disease, compared with those who consumed SSBs infrequently.

"These findings are consistent with the known adverse effects of high sugar intake on metabolic risk factors; and the strong evidence that drinking sugar-sweetened beverages increases the risk of type 2 diabetes, itself a major risk factor for premature death," said study co-author Dr. Walter Willett, professor of epidemiology and nutrition at the same institution.

But what about diet drinks? For the most part, diet drinks — which are sweetened with sugar substitutes — were not linked with an increased risk of death during the study period. Indeed, the study found that replacing one SSB per day with a diet drink was actually tied to a reduced risk of early death.

However, consuming very high levels of diet drinks — four or more servings per day — was linked with an increased risk of early death among women. This finding may have been due to so-called "reverse causation," that is, when people with known heart disease risks (such as high blood pressure and obesity) switch from SSBs to diet drinks. In other words, the people may have switched to diet drinks because of their existing health conditions. But further studies are needed to better examine the link between diet beverage consumption — particularly at high levels — and heart disease, the researchers said.

In a statement regarding the study, the American Beverage Association (ABA) said that it considers soft drinks "safe to consume as part of a balanced diet," and that the sugar used in the beverages is the same as sugar used in other food products. "We don't think anyone should overconsume sugar, that's why we're working to reduce the sugar people consume from beverages across the country," the statement said.

Editor's note: This article was updated on March 19 to include a statement from the ABA.

• 7 Tips for Moving Toward a More Plant-Based Diet
• 9 Disgusting Things That the FDA Allows in Your Food
• 9 New Ways to Keep Your Heart Healthy

Originally published on Live Science.

CHICAGO — Late-night meals may take a toll on heart health, a new study suggests.

The research, presented here today (Nov. 10) at the American Heart Association's Scientific Sessions annual meeting, found that eating more later in the evening was associated with an increased risk of heart disease.

People in the U.S. now have a "delayed lifestyle" — they go to sleep later at night and get fewer hours of sleep, said lead study author Nour Makarem, a postdoctoral fellow in cardiology at Columbia University Vagelos College of Physicians and Surgeons. And with that delayed lifestyle, you also see higher rates of late-night eating, she said. [9 New Ways to Keep Your Heart Healthy]

Makarem and her colleagues thought that this meal timing may play a role in the rise in rates of obesity, high blood pressure and diabetes seen in recent years.

So, they set out to see if that's the case. In the study, the researchers used a database called the Hispanic Community Health Study/Study of Latinos to look at information on more than 12,700 Hispanic and Latino adults ages 18 to 76.

(Though the study looked at just one specific population in the U.S., the Hispanic and Latino population, "we do expect to see similar associations in other populations in the U.S.," Makarem told Live Science. Indeed, several studies conducted abroad have shown that meal timing may be associated with developing risk factors for heart disease, she added.)

In the study, the team looked at data from two separate days in which participants reported their eating habits, and compared this information with measurements such as blood pressure and blood sugar.

They found that over half of the people in the study consumed 30 percent or more of their daily calories after 6 p.m. Those participants had higher levels of fasting blood sugar (a measure of the amount of sugar in the blood when someone hasn't eaten in hours), higher levels of insulin (the hormone that regulates the amount of sugar in the blood), higher levels of HOMA-IR (a marker of resistance to insulin) and higher blood pressure than participants who reported eating less than 30 percent of their daily calories after 6 p.m.

A high fasting blood sugar level can be considered a sign of prediabetes, according to the Mayo Clinic. (Prediabetes means that a person's blood sugar levels are abnormally high, but not high enough to be considered diabetes.) Indeed, the researchers found that those who consumed 30 percent or more of their daily calories after 6 p.m. were 19 percent more likely to develop prediabetes than those who ate more earlier in the day. Seventy percent of people with prediabetes go on to develop type 2 diabetes, which is a risk factor for heart disease, Makarem noted. [Where Is Heart Disease Risk Highest and Lowest? (Maps)]

Those same participants were also 23 percent more likely to develop hypertension, compared with people who ate more earlier the day. These associations were especially common in women, Makarem added.

The late-night link

The study only found an association between meal timing and a person's risk of certain medical problems; it didn't prove a cause-and-effect link.

However, Makarem said that one possible explanation for the link is that problems can arise when our body clocks aren't synced to our environment. Almost every cell in the body can tell time, following a roughly 24-hour cycle. A small part of the brain called the suprachiasmatic nucleus serves as the body's master clock, receiving external light cues (ideally from the sun) and sets the rest of the clocks in the body's cells accordingly, telling people when to wake up, sleep and eat, Makarem said.

"These clocks are regulated by bright-light exposure, but also by behaviors, particularly food signals," Makarem said. So, when we eat at unconventional times — for example, by consuming more calories in the evening — the body's clocks can become misaligned with the master clock, leading to problems in metabolism and increasing the risk for chronic diseases such as diabetes, hypertension and heart disease, she said.

"The evidence is fairly consistent that eating more, later in the day, seems to be worse metabolically," said Kristen Knutson, an associate professor of neurology and preventative medicine at Northwestern Univeristy Feinberg School of Medicine who was not involved with the research, but attended Makarem's talk. These problems arise because "you're not eating at the time that's optimal for your circadian system," she told Live Science.

The findings have not yet been published in a peer-reviewed journal. 

Originally published on Live Science.

Mmm, that spicy-sweet scent that takes over coffee shops, bakeries and entire aisles at the grocery store is a good indication that autumn has arrived. But what is it about this seasonal trend — that is, infusing pumpkin spice flavor into all kinds of treats — that makes it a fall favorite?

The answer has to do with how our brains respond to nostalgia, marketing and the sweet taste that often comes along with the spice, said Catherine Franssen, assistant professor of biopsychology and director of neurostudies at Longwood University in Virginia.

Pumpkin spice is usually a blend of cinnamon, nutmeg, cloves and ginger, with allspice, cardamom and lemon peel occasionally added. (There is nothing "seasonal" about any of these ingredients — nor is there any actual pumpkin typically included.) [Is Pumpkin (Everything) Good for You?]

However, many families eat pumpkin pie and other similarly spiced treats in the fall. So, it's understandable that we've come to associate these smells with the fall holidays. And that smell association then taps into our sense of nostalgia, Franssen said. For instance, the sweet smell of pumpkin spice might remind us of times we helped grandma bake pumpkin pie during Thanksgiving.

Smell is the only one of our senses that is transmitted directly to the amygdala, the emotional center of the brain, according to Franssen. Whenever we come across certain smells, the amygdala can quickly remind us of a specific time, place, feeling or gut instinct, before we even realize it, she said.

So, the familiarity of pumpkin spice flavors can bring back warm memories of home baking, family time, parties and feasts, as well as other positive links with fall. "You smell it — or even see those pumpkin pictures," and the cerebral cortex, the part of the brain that can recall past associations, springs into action, Franssen said. Basically, this part of the brain, "tells the reward part of your brain [the mesolimbic dopaminergic pathway], this [pumpkin spice treat] is going to be great," just like it was last time, Franssen said.

Another big factor in our love for pumpkin spice is how it's marketed. Marketers start advertising pumpkin spice treats in early fall, as pumpkins start to ripen on their vines. Then, advertisers emphasize that pumpkins and pumpkin spice are available for only a limited time. (Why we become more motivated to purchase a limited time item is known as reactance theory, according to a blog post by Jordan Lewis, a neuroscientist at Penn State College of Medicine, on Scitable, which is published by Nature Education.)

Meanwhile, pumpkin spice products also entice consumers via their sweet tooth. Typically, pumpkin spice is presented in a treat, such as a baked good or a sweetened latte. "Our brain really prefers sugar as its nutrient source, because sugar molecules are really small, so they can cross membranes really easily," Franssen said. "And your neurons, [or] brain cells, can use sugar really easily and readily."

Because pumpkin spice-flavored food is typically on the sweet side, several areas of the brain become more active as these seasonal treats are consumed.

"There’s a sugar loading and your brain says 'yay sugar, I'm so excited about sugar,'" Franssen said. "Not only is it a general activation [in the brain], but it's going to light up the reward centers of your brain, like our dopaminergic pathways." This, in turn, stimulates the production of dopamine, a neurotransmitter that helps control the brain's reward and pleasure centers, which then creates the association that sugar is good and makes us want to consume more, according to Franssen.  

Add it all together, and there's pretty good chance that the first sip of the first pumpkin spice latte of the season will make our brains say, "Wow, I really like how this pumpkin spice latte makes me feel," convincing us to indulge in another.

Original article on Live Science.

Starbucks has heard the cries of health-focused consumers: The company has announced that it's testing a lower-sugar version of its famous Frappuccino, according to news reports.

But here's the catch: This "slimmed-down" version still contains twice as much sugar as a candy bar.

Starbucks is testing a lower-sugar caramel Frappuccino in 600 stores in California, Missouri and Rhode Island, according to CBS MoneyWatch. A 16-ounce "Grande" size of the new drink has roughly 25 percent less sugar: It contains 49 grams of sugar, down from 67 grams in the original version, CBS News reported. The new version also contains 50 fewer calories than the original.

But even in this "healthier" form, the sugar content in one of the new caramel Frappuccinos still exceeds the sugar content of many other infamously sugar-laden foods and drinks. For comparison, a 16-ounce regular Slurpee from 7-Eleven has about 36 grams of sugar, a 12-ounce can of Coke has 39 grams of sugar and a 1.5-ounce Hershey milk chocolate bar has 24 grams of sugar.  

And a single lower-sugar Frappuccino will still put you well over the daily recommended amount of sugar: The American Heart Association says that adults should limit the amount of added sugars they consume to no more than 25 grams a day for women and 36 grams a day for men.

Originally published on Live Science.

Type 1 diabetes, or diabetes mellitus, is an incurable disease that requires lifelong treatment. That is, unless you're Daniel Darkes.

About eight years ago, Darkes said, doctors diagnosed him with type 1 diabetes: a potentially life-threatening condition in which the immune system kills off the cells in the pancreas that produce insulin, the hormone necessary for transporting glucose, or sugar, into cells so they can produce energy.

But early last year, routine finger-prick tests showed his blood-sugar levels were normal, so doctors advised him to stop his insulin injections, Darkes said. Now, his doctors have told him they're 80 percent sure he's cured, the Northampton Chronicle and Echo reported. If true, this would mean Darkes could be the first person ever to naturally experience complete remission of type 1 diabetes. [27 Oddest Medical Cases]

Darkes has become a celebrity within the diabetes community, particularly in the United Kingdom, and he was happy to talk with Live Science about his experience.

But does Darkes' story really mean type 1 diabetes can be cured? Darkes declined to provide his medical records, and the experts Live Science spoke to said there were several missing or confusing pieces of information in his story. Usually, incredible medical stories like this one are reported as case reports in the medical literature, the experts said. And even if the details of his story can ultimately be confirmed, the experts emphasized that it's extremely unlikely that Darkes' case would lead to a widespread cure for type 1 diabetes, as reports in the media have wrongly suggested.

A lifelong diagnosis

Darkes, who is 30 years old and an army veteran, lives in Northamptonshire, England. Soon after he left the army, he began feeling symptoms of type 1 diabetes: sweating, blurred vision, tiredness and weight loss. "It lasted three or four days," Darkes told Live Science. "Then I collapsed at work."

Darkes said that a blood test showed his body wasn't producing C-peptide, a by-product of the body's production of insulin, which can reveal how much of the hormone the pancreas makes. Additional tests led doctors to diagnose him with type 1 diabetes, Darkes said.

It's unclear how people get the disease — genetics plays a big role, though unknown environmental factors may also trigger the disease. Either way, the disease causes the immune system to mistakenly attack and kill insulin-producing cells, called beta cells, in the pancreas. (This differs from type 2 diabetes, in which the body initially makes sufficient insulin but the cells cannot properly use it.) Without enough insulin working to remove glucose from the blood stream, and allowing glucose to enter the body's cells, blood sugar levels spike. Left untreated, this insulin deficiency leads to a deadly complication called diabetic ketoacidosis. What's more, having high blood sugar over the long term can cause life-threatening complications such as kidney damage or heart disease, according to the Mayo Clinic.

The primary treatment for type 1 diabetes is lifelong insulin injections and consistent blood sugar monitoring. Darkes said he gave himself insulin injections four times a day to keep his blood sugar levels in check. But something changed in 2016, when he began training intensively for ultramarathons.

Darkes said his blood sugar began crashing, especially at night. Low blood sugar, or hypoglycemia, can cause fatigue, hunger and irritability and, if left untreated, can cause seizures or death.

"That lasted three or four weeks, so I decided to go to my doctor," Darkes said.

He visited Northamptonshire General Hospital, where he said doctors explained that he was experiencing hypoglycemia because his insulin injections were causing his body to remove too much glucose from his blood. Darkes said his doctors also told him that his test results suggested that his diabetes had disappeared.

Live Science requested Darkes' medical records from Northamptonshire General Hospital communications manager Eva Duffy. She said the European Union forbids the release of patient medical records or test results even with a signed waiver. Duffy would not confirm or deny any of Darkes' claims.

"His story surfaced a year and a half ago, and we have never commented on Daniel's situation at any point," Duffy told Live Science.

At the recommendation of his doctors at Northamptonshire General, Darkes said he traveled to St. Louis in January 2017, where he underwent additional testing. First, he said, "I had a microchip placed into my lower back where my kidneys sit to measure protein levels and blood sugar, where it stayed overnight."

But Dr. David Klonoff, a clinical professor of medicine at the University of California San Francisco's Diabetes Center, who specializes in biotechnology for diabetes, was perplexed by the microchip Darkes described.

"My job is to keep up with this stuff," Klonoff told Live Science. "When something's out there, there's a good chance that I've heard about it, but I haven't heard anything about this [technology]." 

When he was in St. Louis, Darkes said, he also underwent a running test "aimed at me personally" (since the doctors knew he was an avid runner), and a blood test to measure key pancreatic molecules and "to see if cells were alive and what percentage," he said.

Darkes said several medical professionals worked with him when he was in St. Louis, but he could name only his senior consultant, Dr. Michael Berk. Berk is an endocrinologist who runs his own practice in St. Louis and is also a clinical associate at Washington University. Because Darkes declined a request to submit a medical release form to Berk's office, Live Science could not confirm key elements of his story, or whether or not he was even a patient of Dr. Berk. 

The results of his medical tests are still being analyzed, Darkes said, but he hasn't needed insulin injections for a year and a half. "It took a long time to sink in," he noted. But Darkes is confident he no longer has type 1 diabetes. He said that doctors told him that he has a "rare" gene that somehow facilitated his cure. "I'm the only one who carries [the gene], at the moment," and there's no further explanation so far, he said.

Too good to be true?

The first media reports of Darkes' supposed cure, along with a similar description of the "rare" gene that partially explained it, began surfacing in February 2017. At the time, Darkes made it clear that his doctors in Northampton were still reviewing the test results, and that they would report on their findings soon. A story published in March 2017 in the Northampton Chronicle and Echo reported that Darkes' test results "are expected to be published next week."

But they haven't been published, and now well over a year has passed. So, what is going on?

"Yes, it's a frustrating case," Darkes told Live Science in an email. "But the doctors have to be as accurate as they can be with what's happened, so they've given a 2-year time scale for completed type 1 reversal." Darkes explained that if he can go without insulin injections for two years, his doctors will be 100 percent sure his diabetes is gone.

Darkes said he asked his doctors if he could share more information about his case with the media but was told "not to give details about the medical case and results at present," he said. "There's nothing I can do until my consultant and team finalize later this year."  

This makes Darkes' story seem less plausible, said Dr. Matthias von Herrath, a professor of developmental immunology at La Jolla Institute in California, and an expert in type 1 diabetes. This type of claim is "earth-shattering," he said. "If it's not well corroborated, it's like your grandmother's rumor kitchen" — there's nothing backing the story. If there is a clinical record and the data are clear, the doctors should publish a case report, Von Herrath told Live Science. 

"The rare-gene story makes me doubt whether this is truly type 1 diabetes," said Bart Roep, a clinical immunologist at City of Hope's Diabetes and Metabolism Research Institute in California. "About 5 to 11 percent of [type 1] diabetic patients are misdiagnosed. What they have is MODY," or maturity-onset diabetes of the young.

MODY is an inherited form of diabetes mellitus caused by a change in one of 11 genes, which results in the body not producing enough insulin, according to Harvard Medical School. MODY can look similar to type 1 diabetes, but its symptoms and treatment vary depending on which of the 11 genes is affected.

"There have been cases where patients were treated with insulin for years until they discovered it was a rare genetic variant" of MODY, Roep told Live Science. Those people are no longer diagnosed as having type 1 diabetes, and they may be able to manage their blood sugar levels with either oral drugs or diet and exercise changes, "but that would not be the same as being cured," Roep said.  

What could be happening

Beta cells, the cells that produce insulin, can regenerate and regain function in some cases, Von Herrath said. There's a wide spectrum of severity when it comes to type 1 diabetes, and that means some people may lose virtually all of their beta cells while others may retain a portion of them.

"What is interesting is that some patients retain beta cell function for over 50 years," he said. "And, it seems if you retain some, that's a lot better." So, for Darkes to still have some functioning beta cells would not be impossible, but it wouldn't eliminate the disease, Von Herrath said. "Depending on how many beta cells he has, maybe his form of type 1 diabetes was not very severe."

"You only need 10 percent of your beta cells to supply sufficient insulin," Roep said. He said there have been a couple of rare cases where a patient had typical type 1 diabetes but could go through long periods without insulin injections. "Insulin needs can be a moving target, and if you have a lifestyle change it's very plausible that you have a lesser need for insulin, and you can deal with [diabetes] with the beta cells you have," Roep said.

Researchers have only recently started to realize that diabetes is a far more diverse disease than they used to believe, Roep said. And every unique case "shows us that we don't know what we think we know," he said. But because of that diversity, "we will never have a magic bullet, drug or pill that will cure everybody."

Von Herrath agreed, and said he's frustrated every time he sees an article or study claiming that a cure for diabetes is on the horizon. It's really not true, he said, and those kinds of statements give people false hope.

All of the experts who spoke with Live Science hope to see evidence of Darkes' story in the scientific literature soon, but they aren't holding their breath. "It's a very strange story," Von Herrath said. "At any rate, wish him good luck."

Original article on Live Science.

Blood sugar, or glucose, is the main sugar found in blood. The body gets glucose from the food we eat. This sugar is an important source of energy and provides nutrients to the body's organs, muscles and nervous system. The absorption, storage and production of glucose is regulated constantly by complex processes involving the small intestine, liver and pancreas.

Glucose enters the bloodstream after a person has eaten carbohydrates. The endocrine system helps keep the bloodstream's glucose levels in check using the pancreas. This organ produces the hormone insulin, releasing it after a person consumes protein or carbohydrates. The insulin sends excess glucose in the liver as glycogen.

The pancreas also produces a hormone called glucagon, which does the opposite of insulin, raising blood sugar levels when needed. According to the Johns Hopkins University Sol Goldman Pancreatic Cancer Research Center, the two hormones work together to keep glucose balanced. 

When the body needs more sugar in the blood, the glucagon signals the liver to turn the glycogen back into glucose and release it into the bloodstream. This process is called glycogenolysis.

When there isn't enough sugar to go around, the liver hoards the resource for the parts of the body that need it, including the brain, red blood cells and parts of the kidney. For the rest of the body, the liver makes ketones , which breaks down fat to use as fuel. The process of turning fat into ketones is called ketogenesis. The liver can also make sugar out of other things in the body, like amino acids, waste products and fat byproducts, according to the University of California. 

Glucose vs. dextrose

Dextrose is also a sugar. It's chemically identical to glucose but is made from corn and rice, according to Healthline. It is often used as a sweetener in baking products and in processed foods. Dextrose also has medicinal purposes. It is dissolved in solutions that are given intravenously to increase a person's blood sugar levels.

Normal blood sugar

For most people, 80 to 99 milligrams of sugar per deciliter before a meal and 80 to 140 mg/dl after a meal is normal. The American Diabetes Association says that most nonpregnant adults with diabetes should have 80 to 130 mg/dl before a meal and less than 180 mg/dl at 1 to 2 hours after beginning the meal. 

These variations in blood-sugar levels, both before and after meals, reflect the way that the body absorbs and stores glucose. After you eat, your body breaks down the carbohydrates in food into smaller parts, including glucose, which the small intestine can absorb.

Problems

Diabetes happens when the body lacks insulin or because the body is not working effectively, according to Dr. Jennifer Loh, chief of the department of endocrinology for Kaiser Permanente in Hawaii. The disorder can be linked to many causes, including obesity, diet and family history, said Dr. Alyson Myers of Northwell Health in New York. 

"To diagnose diabetes, we do an oral glucose-tolerance test with fasting," Myers said.

Cells may develop a tolerance to insulin, making it necessary for the pancreas to produce and release more insulin to lower your blood sugar levels by the required amount. Eventually, the body can fail to produce enough insulin to keep up with the sugar coming into the body.

It can take decades to diagnose high blood-sugar levels, though. This may happen because the pancreas is so good at its job that a doctor can continue to get normal blood-glucose readings while insulin tolerance continues to increase, said Joy Stephenson-Laws, founder of Proactive Health Labs (pH Labs), a nonprofit that provides health care education and tools. She also wrote "Minerals – The Forgotten Nutrient: Your Secret Weapon for Getting and Staying Healthy" (Proactive Health Labs, 2016). 

Health professionals can check blood sugar levels with an A1C test, which is a blood test for type 2 diabetes and prediabetes, according to the U.S. National Library of Medicine. This test measures your average blood glucose, or blood sugar, level over the previous three months. 

Doctors may use the A1C alone or in combination with other diabetes tests to make a diagnosis. They also use the A1C to see how well you are managing your diabetes. This test is different from the blood sugar checks that people with diabetes do for themselves every day.

In the condition called hypoglycemia, the body fails to produce enough sugar. People with this disorder need treatment when blood sugar drops to 70 mg/dL or below. According to the Mayo Clinic, symptoms of hypoglycemia can be:

• Tingling sensation around the mouth
• Shakiness
• Sweating
• An irregular heart rhythm
• Fatigue
• Pale skin
• Crying out during sleep
• Anxiety
• Hunger
• Irritability

Keeping blood sugar in control

Stephenson-Laws said healthy individuals can keep their blood sugar at the appropriate levels using the following methods: 

Maintaining a healthy weight

Talk with a competent health care professional about what an ideal weight for you should be before starting any kind of weight loss program. 

Improving diet

Look for and select whole, unprocessed foods, like fruits and vegetables, instead of highly processed or prepared foods. Foods that have a lot of simple carbohydrates, like cookies and crackers, that your body can digest quickly tend to spike insulin levels and put additional stress on the pancreas. Also, avoid saturated fats and instead opt for unsaturated fats and high-fiber foods. Consider adding nuts, vegetables, herbs and spices to your diet.

Getting physical

A brisk walk for 30 minutes a day can greatly reduce blood sugar levels and increase insulin sensitivity.

Getting mineral levels checked

Research also shows that magnesium plays a vital role in helping insulin do its job. So, in addition to the other health benefits it provides, an adequate magnesium level can also reduce the chances of becoming insulin-tolerant.

Get insulin levels checked

Many doctors simply test for blood sugar and perform an A1C test, which primarily detects prediabetes or type 2 diabetes. Make sure you also get insulin checks.

Additional resources

• Mayo Clinic: Blood glucose Monitors: What Factors Affect Accuracy?
• Oregon State University: Magnesium
• American Diabetes Association: Magnesium Deficiency Is Associated with Insulin Resistance in Obese Children

Is the trick to cutting cravings for sugary foods as simple as getting a good night's sleep? A new small study from the United Kingdom suggests that may be the case.

It's no surprise that tossing and turning all night can cause a person to feel tired, cranky and out of sorts the next day. But missing out on the recommended minimum of 7 hours of nightly shut-eye is also linked to various health conditions, such as obesity and cardiometabolic diseases, which include diabetes, heart disease and stroke, according to the study, published today (Jan. 9) in The American Journal of Clinical Nutrition.

Earlier research has shown that more than one-third of U.S. adults get 6 hours or less of sleep each night — less than the recommended 7 to 9 hours, according to the study. With that in mind, the researchers chose to examine whether a sleep consultation could help adults get more shut-eye and how doing so might affect their daily nutrient intake. [The Science of Hunger: How to Control It and Fight Cravings]

In the study, the researchers recruited 21 individuals to participate in a 45-minute sleep consultation designed to extend their sleep time by up to 1.5 hours per night. Another group of 21 participants were also recruited but did not receive intervention in their sleep patterns, therefore serving as the control group, according to the study.

All of the participants were asked to record their sleep and dietary patterns for seven days. During this time, the participants also wore motion sensors on their wrists that measured the exact amount of sleep they got each night, as well as the amount of time they spent in bed before they actually fell asleep.

The results showed that the participants who increased the amount of sleep they got each night reduced their added sugar intake by as much as 10 grams the next day compared with the amount of sugar they consumed at the beginning of the study. These participants also had a lower daily carbohydrate intake than the group that did not extend their sleep patterns, the study found.

"The fact that extending sleep led to a reduction in intake of [added] sugars, by which we mean the sugars that are added to foods by manufacturers or in cooking at home, as well as sugars in honey, syrups and fruit juice, suggests that a simple change in lifestyle may really help people to consume healthier diets," senior study author Wendy Hall, a senior lecturer in the Department of Diabetes and Nutritional Sciences at King's College London, said in the statement.

The group that got more sleep received a list with suggestions for how to help them get a better night's sleep — such as avoiding caffeine before bedtime, establishing a relaxing routine and not going to bed too full or hungry — as well as a recommended bedtime suited to their lifestyle.

"Sleep duration and quality is an area of increasing public health concern and has been linked as a risk factor for various conditions," lead researcher Haya Al Khatib, a professor from in the Department of Nutritional sciences at King's College London, said in the statement. "We have shown that sleep habits can be changed with relative ease in healthy adults using a personalized approach."

Overall, the results of the study showed that 86 percent of the participants who received sleep advice increased their total time spent in bed, and 50 percent of the participants extended their sleep duration by roughly 52 to 90 minutes each night, compared with the control group. What's more, three participants in the sleep-extension group achieved a weekly average within the recommended 7 to 9 hours, the researchers said.

However, the researchers noted one caveat to their findings: The data suggested that the extended amount of sleep may have been of lesser quality than the sleep of the participants in the control group. This is likely because any new routine requires an adjustment period, the researchers said.

"Our results also suggest that increasing time in bed for an hour or so longer may lead to healthier food choices," Al Khatib said in the statement. "This further strengthens the link between short sleep and poorer-quality diets that has already been observed by previous studies. We hope to investigate this finding further with longer-term studies examining nutrient intake and continued adherence to sleep-extension behaviors in more detail, especially in populations at risk of obesity or cardiovascular disease."

Originally published on Live Science.

Is alcohol good or bad for your health? With no shortage of contradictory findings, it's understandable if you're left feeling like you've had a little too much to drink.

Now, new research from Denmark suggests that moderate levels of alcohol drinking — not binge drinking — may be linked to a lower risk of developing diabetes. But it's not just how much people drink, but how often they drink, that plays a role, the researchers said.

It's important to note, however, that most experts recommend that if you don't already drink alcohol, you shouldn't start because of possible health benefits.

In the study, published today (July 27) in the journal Diabetologia, researchers found that drinking alcohol three to four days a week was associated with a lower risk of diabetes compared with drinking less than one day a week. [7 Ways Alcohol Affects Your Health]

The "findings suggest that alcohol drinking frequency is associated with risk of diabetes, and that consumption of alcohol over three to four days per week is associated with the lowest risk of diabetes, even after taking average weekly alcohol consumption into account," the researchers, led by Charlotte Holst, a doctoral student of public health at the University of Southern Denmark, wrote.

Danish data

In the study, the researchers looked at data on more than 76,000 adults who participated in the Danish Health Examination Survey in 2007 to 2008. The people in the study filled out questionnaires about their drinking habits, including how much and how often they drank alcohol, and what type of alcohol they drank. Using information from the Danish National Diabetes Register, the researchers determined if the people in the study developed diabetes.

The researchers noted that they weren't able to distinguish between type 1 diabetes and type 2 diabetes using the available data. However, it's more common to develop type 2 diabetes as an adult than type 1 diabetes, which usually develops during childhood.

The people in the study were tracked for a median of 4.9 years, the researchers wrote. Over this time period, about 850 men and 890 women developed diabetes. 

What and when you drink

In men, drinking alcohol three to four days per week was associated with a 27 percent lower risk of diabetes compared with drinking less than one day per week, the researchers found. For women, the same frequency was associated with a 32 percent lower risk.

The researchers also looked at the amount of alcohol consumed. Their findings were similar to those of earlier studies, which have shown that drinking a moderate amount of alcohol is associated with the lowest risk of diabetes. Specifically, the study found that for men, drinking 14 drinks per week was associated with a 41 percent lower risk of diabetes compared with no drinks, and for women, drinking nine drinks per week was associated with a 58 percent lower risk of diabetes.

When the researchers looked at alcohol type, they found that different alcohol types were associated with different levels of risk. For example, drinking seven or more glasses of wine per week was associated with a 25 to 30 percent lower risk of diabetes compared with drinking less than one glass of wine per week.

There were also differences between men and women: For beer, for example, drinking between one and six brews was associated with a 21 percent lower risk of diabetes in men compared with drinking less than one beer a week, and there was no link found between beer consumption and diabetes risk in women. Drinking seven or more drinks made with liquor per week, on the other hand, was associated with an 83 percent increased risk of diabetes in women compared with one liquor-based drink per week. [Here's How Much Alcohol Is OK to Drink in 19 Countries]

The study only looked at the association between drinking alcohol and risk of diabetes — it didn't prove cause and effect. However, the researchers hypothesize that wine's beneficial effects may stem from compounds called polyphenols, which may help the body control blood sugar levels and, in turn, lower a person's risk of diabetes, according to the study.

The researchers noted that they didn't find an association between binge drinking (defined in the study as drinking five or more drinks at a time) and diabetes risk, but this may be because there weren't enough binge drinkers in the study to observe a link. In other words, it's possible that binge drinking is linked to diabetes risk, but more research is needed.

One limitation of the study was that the people self-reported their alcohol consumption, which means that it could be inaccurate, the researchers wrote.

Originally published on Live Science.

Washing down your bacon cheeseburger with a big, cold soda may trigger the body to store more fat than it would if you drank something without sugar, a new small study finds.

When the people in the study added a sugary drink to a protein-rich meal, their bodies’ fat-burning ability decreased by 8 percent on average, the researchers found. In addition, the sugary drinks also appeared to increase their food cravings after the meal.

"We were surprised by the impact that the sugar-sweetened drinks had on metabolism when they were paired with higher-protein meals," lead study author Shanon Casperson, a research biologist at the U.S.  Department of Agriculture's Agricultural Research Service, said in a statement. [11 Ways Processed Food is Different from Real Food]

"This combination also increased study subjects' desire to eat savory and salty foods for four hours after eating," Casperson added.

Indeed, earlier research has shown that people who increase their protein intake experience changes  both in how food is processed by their body and in how much they eat, according to the study, published July 20 in the journal BMC Nutrition. For example, research suggests that a higher protein intake is linked to an increase in the body's fat-burning abilities.

The new findings suggest that adding sugary drinks to a high-protein intake may have the opposite effect: The sugar-rich beverages may slow the body's burning of fat, according to the study.

Isolation chambers

For the study, the researchers recruited 27 healthy young adults, gave them special meals and then observed them in special isolated rooms called "room calorimeters."  The rooms had a bed, a toilet, a sink and some other furniture, and equipment to measure the levels of oxygen and carbon dioxide along with temperature and air pressure. These measurements allowed the researchers to calculate how the foods the participants ate affected their metabolism, including how many calories they burned and how they broke down fat, protein and carbohydrates.

The participants spent two 24-hour periods in the rooms. Each period started at 4 p.m., and each participant had dinner at 5 p.m. in the chamber. The participants then fasted until breakfast the next morning. [8 Reasons Our Waistlines Are Expanding]

Then, the experiment really began. During one stay in the room, the participants were served breakfast and lunch meals that each contained 15 percent protein. Each meal was served with a sweet drink that contained either sugar or an artificial sweetener. If the drink with sugar was served at breakfast, the participant received the artificially sweetened drink at lunch, and vice versa. This allowed the researchers to see if there was any difference between how the meal was metabolized when it was combined with sugar, versus without sugar.

After both breakfast and lunch, the participants were observed for 4 hours. During this time, the researchers could see how the body responded to the meal with either a sugary drink or an artificially sweetened drink.

During their other stay in the room, the participants were served breakfast and lunch meals that each contained 30 percent protein. 

The researchers found that when a sugar-sweetened beverage was served with a meal, the participants' fat-burning ability was 8 percent lower than it was when the meal was served with an artificially sweetened drink. In addition, although the sugary drinks added more calories to the meals, they didn't cause the participants to feel fuller after eating.

In other words, sugary drinks seem to decrease the body's fat burning and don't contribute to feeling fuller. The findings "provide further insight into the potential role of sugar-sweetened drinks — the largest single source of sugar in the American diet — in weight gain and obesity," Casperson said.

More research including more people over a longer period is needed to confirm the findings.

Originally published on Live Science.

A new breed of green grape isn't fluffy or flossy, but it tastes just like cotton candy, according to news sources.

The carnival-evoking taste isn't the product of genetic engineering or artificial flavors, but rather the result of regular plant breeding, NPR reported.

"When you go to the supermarket, there's, like, 15 kinds of apples — Fuji, Pink Lady, Gala, Braeburn. The list goes on," David Cain, a horticulturalist in charge of fruit breeding at International Fruit Genetics in Bakersfield, California, told NPR. "We want to give consumers the same array of flavors for grapes." [Chew on This: 8 Foods for Healthy Teeth]

To make the Cotton Candy grape, Cain and his colleagues hybridized two grape species: a type of Concord-like grape (the grape used in Welch's jams, jellies and juices) and a variety of Vitis vinifera, a common grape found at grocery stores across the country, Cain told NPR.

The result was a sugary-sweet hybrid: for every 100 grams (0.2 lbs.) of grapes, there's about 18 g (0.03 lbs.) of sugar, NPR reported. That's about 12 percent more sugar than typical store-bought grapes, NPR said.

Besides the Cotton Candy grape, researchers are also working on breeding hybrid grapes that taste like strawberries, pineapples and mangos, Cain said.

The result may be sweet, but making them was laborious. Because seedless grapes are unable to reproduce without help, horticulturalists had to remove the grapes' embryos from the plants and transfer them to individual test tubes, where they grew before being planted in a field, according to NPR.

In all, Cain made about 100,000 test tubes before he came across the cotton-candy-tasting gem, NPR reported. The extra-sweet grapes hit supermarket shelves in 2011, but it wasn't until this year that Grapery, the grapes' distributor, ramped up production from the original 2 acres to 100 acres (0.8 to 40 hectares), Cain told NPR.

"The whole process takes at least six years and sometimes up to 15 years," to create a new grape hybrid, Cain told NPR. But these sweet bites are doing well in supermarkets. The Cotton Candy grapes cost about $6 per lb. (0.4 kilograms), more than twice the price that seedless grapes cost in 2016 ($2.88/lb.), according to Statista, a company that provides statistics. 

But that price hasn't deterred customers, especially those looking for a sweet snack.

"A lot of fruit becomes tasteless by the time somebody buys it," Cain told NPR. "We want to change that."

Original article on Live Science.

A major doctors' group hopes to put an end to a great irony served up daily at most U.S. hospitals: The food offered there tends to contribute to obesity, diabetes, heart disease, stroke and cancer — the very same conditions for which many of the hospital patients are seeking treatment.

Refried, frozen chicken patties on doughy white bread; greasy pizza slices that turn the paper plate translucent; waxy, flavorless beans poured straight from a can constituting the only vegetable option; orange drink purporting to have 10 percent real orange … So much for a hospital being a beacon of health.

At its annual meeting on June 14, the American Medical Association (AMA) House of Delegates, which represents more than 200,000 physician members, issued a policy statement that called for the reduction of sugar-sweetened beverages and processed meats, and an increase in the availability of healthful, plant-based foods in hospitals. [7 Foods You Can Overdose On]

Under the resolution, physicians and hospital staff are encouraged not only to counsel their patients about the health consequences of a poor diet but also to lead by example by offering healthier foods at the hospital.

Specifically, the resolution states that the "American Medical Association hereby call on U.S. hospitals to improve the health of patients, staff, and visitors by (1) providing a variety of healthful food, including plant-based meals and meals that are low in fat, sodium, and added sugars, (2) eliminating processed meats from menus, and (3) providing and promoting healthful beverages."

Removing sugary drinks from vending machines and replacing them with water, unflavored milk, and unsweetened teas and coffees may be the easiest place to start making hospital food choices healthier, according to the AMA.

"Excessive sugar consumption has been linked to some of the nation's most debilitating diseases, and limiting the consumption of sugar-sweetened beverages will go a long way toward helping people prevent the onset of these diseases, improve health outcomes and rein in health costs associated with chronic diseases," Dr. William E. Kobler, an AMA board member who was part of the policy decision, said in a statement from the organization.

Yet health experts have lamented for years that hospitals' food options, not just the drinks, are unhealthy — a concept that contradicts hospitals' health-oriented mission. A study published in 2002 in the Journal of the American Medical Association found that more than a third of the top 16 U.S. hospitals had contracts with fast-food restaurants to offer their food in the hospital.

Similarly, a 2014 study conducted by the Physicians Committee for Responsible Medicine (PCRM), a nonprofit health group of 12,000 doctors who advocate plant-based diets, found that more than 20 percent of the 208 hospitals they surveyed housed fast-food restaurants. The same study found that the cafeteria food in these hospitals, where the staff eats every day, was dominated by foods that were high in sugar, salt and cholesterol, such as processed meats. [9 Snack Foods: Healthy or Not?]

Speaking at the AMA meeting, PCRM President Dr. Neal Barnard compared unhealthy food served in hospitals to tobacco. "A generation ago, the AMA supported doctors who were working to get tobacco out of their hospitals. And that helped everyone, especially those patients who needed to break a bad habit," Barnard said in testimony.

Barnard noted that, as with cigarettes, hot dogs and similar processed meats are now known to contain cancer-causing agents. "[M]any doctors and administrators would like to replace them with healthier foods," he said.

The Washington, D.C.-based PCRM started a national campaign in 2016 to encourage hospitals to ban processed meats such as hot dogs, which are a choking hazard for children. Several hospitals have since pledged to remove these foods as a result of the campaign.

The tide may be turning elsewhere, as well. A 2015 study published in the journal Preventive Medicine Reports found that creating hospital gardens for staff, patients and the community can lower rates of obesity in communities they serve and reduce public health disparities by providing more people with easy access to fresh, healthy, plant-based foods. More than 100 hospitals have such gardens, the study found.

So the day might come when you can go to the hospital to fix a broken leg and not have to return for a hospital-food-induced angioplasty.

Other policy resolutions announced at the AMA meeting included reducing the consumption of sugary drinks nationwide, destigmatizing obesity, strengthening vaccine policy and using the phrase "gun violence mitigation" in lieu of "gun control," among 11 other resolutions.

Follow Christopher Wanjek @wanjek for daily tweets on health and science with a humorous edge. Wanjek is the author of "Food at Work" and "Bad Medicine." His column, Bad Medicine, appears regularly on Live Science.

Want to reset your biological clock? Try eating at a different time of day.

New research suggests that shifting your meal time can also shift your body's internal clock, meaning that recovering from jet lag or adjusting to a shift-work schedule might be easier if you also adjust your eating times.

The body's biological clock, or circadian rhythm, is controlled by a "master clock" found deep in the brain and called the suprachiasmatic nucleus, according to the study, published June 1 in the journal Current Biology.

But other clocks, called "peripheral clocks," are found throughout the body. These peripheral clocks are essentially molecules in cells that respond to signals from the master clock and help control certain metabolic functions in those cells' region of body. Clocks in the liver and pancreas are involved in controlling rises and falls in blood sugar levels, for example. If peripheral clocks fall out of sync with the master clock, it can result in problems with a person's metabolism. [10 Things You Didn't Know About You]

Researchers know that exposure to light at the appropriate time and the use of melatonin supplements can help the master clock in the brain adjust to new time zones, said senior study author Jonathan Johnston, a chronobiology and integrative physiology researcher at the University of Surrey in England. "But light and melatonin probably have little direct effect" on the metabolic rhythms that are controlled by the body's peripheral clocks, he said.

In other words, although a person may nudge his or her master clock toward a new time zone by getting exposure to light at the right time, not all the clocks in the person's body will catch up right away.

The peripheral clocks that control blood sugar levels influence how much sugar is taken from the blood and how much is released back into the blood, Johnston said.

"The way the body processes a meal varies over the day," Johnston said. For example, when a person eats at night, blood sugar levels rise higher and stay elevated for longer compared with how blood sugar levels respond to a meal eaten earlier in the day.

In the new study, Johnston and his team found that this relationship can also work in the opposite direction: Changing the time of day that a person eats can shift the circadian rhythm of blood sugar levels.

To study the effects of meal timing on circadian rhythm, the researchers invited 10 healthy men to live in a lab for 13 days so the researchers could closely observe how the subjects' bodies responded to different eating schedules. The men wore monitors to collect data on their sleep. For the first three days of the study, the men were given breakfast 30 minutes after waking up, followed by lunch 5 hours later and dinner 5 hours after that. All of the meals had the same number of calories and the same amounts of carbohydrates, fat and protein.

After three days on this schedule, which the researchers called the "early meal" schedule, the men were not allowed to sleep for 37 hours. During this time, the lights in the lab were kept dim, so the men didn't experience the changes in light that might signal the time to their biological clocks. They were given food on an hourly basis, but nurses in the lab nudged the men if they looked like they were dozing, Johnston said. [The Spooky Effects of Sleep Deprivation]

Then, the eating schedule began again, but this time, instead of eating 30 minutes after waking up, the men didn't eat until they had been awake for 5 hours. This "late meal" schedule went on for six days, and then the men repeated the 37-hour period of being continuously awake.

The impact of meal timing

The researchers found that after the men shifted their meal schedules by 5 hours, the rhythms of their blood sugar levels also shifted by 5 hours, Johnston said.

During the participants' 37-hour periods of being awake, the researchers measured various components of the men's circadian rhythms: Blood was drawn every hour to look at levels of certain hormones and gene expression, and every 6 hours, a small sample of fat tissue was taken from the buttocks.

The researchers found that, aside from the changes in the rhythm of blood sugar levels, many other components of the men's circadian rhythms didn't change. For example, there were no changes in the normal rises and falls in melatonin (the sleep hormone) or cortisol (the stress hormone) after the late meal schedule compared to the early meal schedule. This suggests that the changes observed after the late meal schedule were due to changes in the peripheral clocks and not the master clock, which controls hormone release, Johnston said.

The new findings suggest that to adjust to a new time zone or a different work schedule, a person can add "appropriate timed" meals to his or her regimen, in addition to exposing himself or herself to light at the appropriate times, Johnston said.

"A general strategy might be that people could adjust their meal times to the destination time zone before a flight," Johnston said. "It should be stressed, however, that this is speculation at the moment," as more studies are needed to confirm the findings, he added.

Johnston also noted that the findings may be more valuable to shift workers than people adjusting to jet lag. "For most people, jet lag is a fairly short-term inconvenience and not a long-term health problem," he said. 

Originally published on Live Science.

Endurance athletes such as marathon runners and long-distance cyclists know that it takes years of training to build stamina. But new research in mice suggests that it may not take much time at all.

In the study, scientists gave mice that were typically sedentary a chemical called GW1516 for eight weeks, and found that these mice were able to run on a treadmill for 270 minutes before they showed signs of fatigue. Mice in a control group that did not receive the pill could run on the treadmill for only about 160 minutes.

The chemical is thought to work by interacting with a gene involved in the switch from burning the body's stores of sugar to burning fat, according to the findings, published today (May 2) in the journal Cell Metabolism. [Exercise and Weight Loss: The Science of Preserving Muscle Mass]

"If you reprogram the genetics, you can acquire that level of fitness without having to expend a lot of energy," said Ronald Evans, an author of the study and a molecular and developmental biologist at the Salk Institute in La Jolla, California.

It's not clear whether the chemical would work the same way in humans. But if it did, the results from the study could one day lead to a pill that controls a network of genes, turning them on and off to selectively burn fat and sugar, much like exercise training. Such a therapy could mimic the benefits of exercise for those with limited mobility, such as the elderly, obese or physically impaired.

In the new study, Evans and his team built on earlier work in which they found a kind of biological sensor called PPARD that, during exercise, senses fat in the muscle and then turns genes on and off to burn fat and preserve sugar. [Dieters, Beware: 9 Myths That Can Make You Fat]

Previous work also showed that GW1516 interacted with that sensor, activating the same set of genes as those that would be triggered by exercise. For example, in one study, Evans and his team gave GW1516 to normal mice for four weeks and showed that it controlled their weight and insulin response. But it didn't seem to influence endurance in sedentary mice.

In the new study with sedentary mice, they increased the dose of GW1516 and gave the compound over a longer period.

When the scientists analyzed muscle tissue from the mice, they found a few interesting things. First, the tissue did not show any of the physiological changes associated with fitness training. There was no increase in the number of blood vessels or mitochondria, the power plants in cells that generate more than 90 percent of the energy.

"What's interesting to me here is that there is no change in fiber type or mitochondrial content, and that the improvement in endurance from GW1516 is primarily, or overwhelmingly, due to differences in glucose management," said Evan Williams, senior research scientist at the Institute of Molecular Systems Biology at ETH Zurich, a university in Switzerland known for its science and technology programs. Williams is not a part of this research study.

Second, Evans and his team saw that the chemical had affected a network of 975 genes. Genes that were involved in burning fat were turned on and up, and genes involved in the breakdown of sugar for energy were silenced.

The scientist think that, at least in muscle, the PPARD sensor facilitates the switch to burning fat for energy, not sugar, Evans said. Even though muscle tissue can burn both, the brain can use only sugar from the blood for energy. And that is where endurance comes from, Evans said. When sugar levels in the blood drop, the brain is affected, and fatigue sets in.

Endurance athletes that push themselves to their limits and deplete their sugar reserves ultimately "hit the wall," or "bonk," as it's colloquially called. But if their muscles could burn less sugar and reserve it for the brain, they could push back the wall.

If the GW1516 chemical sounds like a performance enhancing drug, it is, Evans said. The compound, which is not an approved drug for use in humans in the United States, is being made and used in Russia, Evans said.

"That doesn't mean we shouldn't develop the drug for the people who need it," he said.

Marc Hamilton, a professor at the University of Houston and director of Texas Obesity Research Center at the Texas Medical Center, said he is skeptical that any drug would be powerful enough to raise fat and glucose metabolism in people, even to the degree that occurs during moderate exercise, which has been shown to be safe and without hazardous side effects. 

Such a solution should "come through an innovative breakthrough by creating physiologically effective exercise-like metabolism in any body by better forms of natural muscular activity, without the risks of drugs and high effort exercise prescriptions," said Hamilton, who was not a part of this study.

Williams, at ETH Zurich, said he is curious about future studies that will focus on whether GW1516 can be used as a therapy.

"The experiments in this paper are geared towards supporting its ability for athletic performance enhancement," he said. "It'd be useful to see additional research on this compound in models that represents metabolic diseases or some sort of dystrophy."

Original article on Live Science.

People who often drink soda, with sugar or without it, may be more likely to develop memory problems and have smaller brain volumes, according to two recent studies.

In one study, researchers found that people who drank diet soda every day were three times more likely to have a stroke or develop dementia over 10 years than those who did not consume any diet soda.

In the second study, the same researchers concluded that people who consumed at least one diet soda a day had smaller brain volumes than those who did not drink any diet soda. Moreover, that same study found that people who consumed more than two sugary beverages such as soda or fruit juice a day had smaller brain volumes and worse memory function that those who did not consume any such beverages. [7 Biggest Diet Myths]

Although both studies show that there is a link between drinking diet or sugary beverages and certain health outcomes, the results do not mean that consuming such beverages directly causes these outcomes, said the lead author of both studies, Matthew P. Pase, a neurology researcher at Boston University School of Medicine.

In the first study, published April 20 in the journal Stroke, the researchers interviewed about 4,300 people, ages 45 and older, three times over seven years, and asked them whether they drank any diet or sugary beverages. Then, toward the end of the seven-year period, the scientists began to monitor the study participants' health for cases of stroke and dementia, and continued to do so for the next 10 years. During this period, 97 people had a stroke and 81 people developed dementia — a number that included 63 cases of Alzheimer's disease.

The researchers found that the daily consumption of diet beverages, but not sugary beverages, was linked to a higher risk of stroke and dementia over the 10-year period. The reasons behind these findings are not clear, but previous research had linked the consumption of diet drinks with obesity and diabetes, which might also be linked to with poor blood circulation, Pase said. Problems with circulation may contribute to a person's risk of stroke or dementia because the brain relies on a constant supply of blood to function well, he said.

The findings of this study suggest that turning to diet beverages in the hope of avoiding extra calories from sugary drinks may not be a good idea, said Dr. Paul Wright, chairman of neurology at North Shore University Hospital in Manhasset, New York, who was not involved in the study. "The right direction to go in is to have plain water," or other beverages that do not contain artificial sweeteners, he told Live Science. [7 Foods You Can Overdose On]

In the second study, published in March in the journal Alzheimer's & Dementia, the researchers looked at brain scans and results of cognitive tests conducted in about 4,000 people. The scientists also asked the study participants if they consumed any diet or sugary beverages, and, if so, how much.

The data revealed a link between the consumption of both diet and sugary beverages and smaller brain volumes. Moreover, the researchers found a link between the consumption of sugary beverages and poorer memory. All of those outcomes are risk factors for Alzheimer's disease, the researchers said.

As with the first study, the mechanisms that might underlie the link between the consumption of sugary beverages and these outcomes are unclear, Pase told Live Science. However, previous research has linked high sugar intake with diabetes and high blood pressure — conditions linked to compromised blood circulation that may ultimately affect brain health, he said.

Originally published on Live Science.

The new Starbucks Unicorn Frappuccino is getting a lot of attention for its sky-high sugar content, but it's not the chain's most sugar-filled beverage.

The Unicorn Frappuccino, which is available only for a limited time, has 59 grams of sugar in a 16-ounce "Grande" size, according to nutrition information posted on Starbucks' website. This is indeed a lot of sugar, and has led to headlines calling it a "Sugar Bomb" and an "Unsurprising Surprise." 

But several other Frappuccinos already on Starbucks' menu have more sugar. Two drinks can claim the title of "most sugary" Frappuccino: the Caffè Vanilla Frappuccino and the Pokémon GO Frappuccino, another limited-time drink that was introduced last December. Both drinks have 69 grams of sugar in a Grande size, a full 10 extra grams more than the Unicorn Frap. (Perhaps Starbucks reasoned that Pokémon GO players might need an extra sugar boost while catching 'em all?)

The Caramel Frappuccino, Java Chip Frappuccino and Cotton Candy Crème Frappuccino all have 66 grams of sugar in a Grande size. [9 Snack Foods: Healthy or Not?]

For comparison, a 16-ounce regular Slurpee from 7-Eleven has about 36 grams of sugar, a 12-ounce can of Coke has 39 grams of sugar, and a 1.5 ounce Hershey milk chocolate bar has 24 grams of sugar.  

All of the Frappuccinos listed above have more sugar than health expert recommend people consume in an entire day. According to the American Heart Association, adults should limit the amount of added sugars they consume to no more than 25 grams a day for women and 36 grams a day for men.

Original article on Live Science.

Contact lenses packed with transparent sensors might one day help people with diabetes to monitor their blood sugar levels, a new study finds.

These sugar-sensing lenses would give people a way to check their blood sugar levels without drawing blood, according to the scientists who are developing on the ices.

Typically, people with diabetes monitor their blood sugar by making a tiny prick in their fingertip to draw blood, and then using a small device to measure blood sugar levels. It hurts, and some have to do this several times a day. [9 Healthy Habits You Can Do in 1 Minute (Or Less)]

But the proposed contact lenses could continuously monitor a person's blood sugar levels throughout the day, said study co-author Gregory Herman, a chemical engineer at Oregon State University. Such continuous monitoring could help reduce the risk of diabetes-related health problems, by alerting someone about any major changes in his or her blood sugar levels right when they happen, Herman said. (In an individual who has diabetes, the body cannot effectively transport sugar, or glucose, from the blood to that person's cells. Too much glucose in the blood can lead to medical problems.)

Devices that continuously monitor blood sugar levels are available, but they often require the insertion of electrodes under the skin, which can be painful, lead to skin irritation or infections, and must get replaced every several days. Contact lenses that could continuously and noninvasively monitor blood sugar levels could eliminate many of these problems, Herman said. And because contact lenses are virtually invisible, people could use them without feeling self-conscious, he added.

From electronics to eyes

To make the blood-sugar-monitoring contact lens, the researchers used technology that was originally developed for electronic products. Specifically, the researchers tinkered with a material called indium gallium zinc oxide (IGZO), whose electronic properties have recently helped boost the image quality in smartphone, tablet and flat-panel displays while also saving power and improving touch-screen sensitivity.

"If you buy an iPhone or an Apple computer or a flat-screen TV nowadays, they use IGZO," Herman told Live Science. He presented his findings on April 4 at the national meeting of the American Chemical Society in San Francisco.

In the study, the researchers made contact lenses that included transparent sheets of transistors made with IGZO. To test if the lenses could measure glucose levels, the transistors were coated with an enzyme called glucose oxidase, which breaks down sugar. This meant that when the contact lenses were exposed to glucose, a chemical reaction took place as the enzyme broke down the sugar. The transistors measured this reaction — which indicated that glucose was present — through changes in the electrical currents that flowed through the lenses.

The researchers found that the sensors could detect even very low concentrations of glucose, such as the levels typically found in tears.

In theory, more than 2,500 of these sensors could be embedded within a 1-square-millimeter patch of a contact lens, Herman said. And by using Wi-Fi or Bluetooth, the data collected by the lenses could be wirelessly transmitted to smartphones or other devices, he said. [10 Technologies That Will Transform Your Life]

Beyond blood sugar

But measuring blood sugar levels isn't the only potential use for biosensing contact lenses, Herman said. The lenses could also be used to help monitor a range of other conditions, such as cancer, AIDS, glaucoma, and kidney or liver disease, the researchers said.

For example, sensors could be developed to measure a chemical called uric acid, which is found in higher levels in people with kidney disease or gout. Additionally, sensors that measure lactate could help monitor liver disease or sepsis; and sensors for the neurotransmitter dopamine could help monitor glaucoma, he said.

"You could also look for molecules related to HIV or cancer," Herman said. "We want to see if there are good ways to catch cancer at very early stages, before it's a fatal disease."

Herman cautioned that the lenses are still in the very early stages of development. It could be a year or more before a prototype biosensing contact lens is ready for animal testing, he said. And tests in humans are even further off, he said.

Original article on Live Science.

Are rising temperatures around the world also increasing the rates of diabetes? A new study from the Netherlands suggests that there may be a link between warming global temperatures and a higher prevalence of the disease, but not all experts are convinced.

When the researchers analyzed average global temperatures and the rates of type 2 diabetes, they found that a 1.8-degree Fahrenheit (1 degree Celsius) increase in temperature was associated with an increase of 0.3 cases of diabetes per 1,000 people. In the United States, that would be the equivalent of more than 100,000 new cases of type 2 diabetes each year, according to the study, published Monday (March 20) in the journal BMJ Open Diabetes Research & Care.

The new research may be interesting, but it shows only an association between rising temperatures and diabetes rates, said Dr. Christian Koch, a professor of endocrinology at the University of Mississippi Medical Center who was not involved in the new study. Although both temperatures and diabetes rates are rising, "there's no causality" between the two, Koch added. [5 Ways Climate Change Will Affect Your Health]

Importantly, the study did not include two key factors when looking at this association: physical-activity levels and indoor climate control — namely, air conditioning, Koch told Live Science.

A possible link?

The study looked at the rates of type 2 diabetes in all 50 states, along with Guam, Puerto Rico and the U.S. Virgin Islands from 1996 to 2013. In addition, the researchers looked at data on the average temperatures in each state and territory for the same years.

Overall, the rate of people being diagnosed with type 2 diabetes was higher in warmer years, the researchers found.

Data on worldwide type 2 diabetes rates was not available, the researchers noted. Instead, they used World Health Organization data on the rates of high blood sugar levels, a factor that is linked to diabetes.

For each 1.8-degree-Fahrenheit increase in average temperatures worldwide, the average rates of high blood sugar increased by 0.2 percent, the researchers found.

The findings suggest that, overall, the rates of diabetes in the United States and the rates of high blood sugar around the world increased with higher outdoor temperature worldwide, the researchers wrote in the study. 

Brown fat

The potential link between rising temperatures and diabetes lies in a type of fat called brown adipose tissue, or brown fat, according to the study. [What Is Brown Fat? 5 Fascinating Facts]

Brown fat is metabolically active; it can break down smaller fat molecules to generate heat, the researchers wrote. Previous research has found that colder temperatures can activate brown fat and may lead to modest weight loss, according to the study.

Additionally, in a small study published in the journal Nature Medicine in 2015, a group of researchers found that when patients with type 2 diabetes were exposed to moderately cold temperatures for 10 days, their insulin sensitivity improved. (Decreased sensitivity to insulin, or insulin resistance, can put people on the path to type 2 diabetes.)

The researchers hypothesized that, based on the possible effects of brown fat on insulin, combined with the findings that cold temperatures activate it, warmer temperatures could have the opposite effect — namely, they could be linked to a decrease in insulin sensitivity and an increase in type 2 diabetes.

Not so simple

Koch noted, however, that most people spend the majority of their days exposed to indoor temperatures, and therefore, outdoor temperatures would not have such a significant effect.

In addition, he said the researchers found that increased temperatures had different effects on diabetes rates in two neighboring states: In Louisiana, the rates decreased, but in Mississippi, they increased. If temperature played a role, the findings would be similar in both states, he said.

The study authors, led by Lisanne Blauw, an endocrinology researcher at the Leiden University Medical Center in the Netherlands, noted that their findings do not prove cause and effect. In other words, the study does not prove that rising temperatures directly cause rising diabetes rates but rather highlights an important area of future research.

"These findings emphasize the importance of future research into the effects of environmental temperature on glucose metabolism and the onset of diabetes, especially in view of the global rise in temperatures, with a new record set for the warmest winter in the USA last year [2015]," they wrote. 

In addition, the researchers described several limitations of the study. They noted that because the study was observational, confounding factors might have affected the results. In other words, there might have been other factors that had an effect on the results. In addition, the researchers were not able to account for changes in body mass index, which is associated with type 2 diabetes, over time because of a lack of available data.

Originally published on Live Science.

Nearly half of all deaths from heart disease, stroke and type 2 diabetes may be due to diet, a new study finds.

In 2012, 45 percent of deaths from "cardiometabolic disease" — which includes heart disease, stroke and type 2 diabetes — were attributable to the foods people ate, according to the study.

This conclusion came from a model that the researchers developed that incorporated data from several sources: The National Health and Nutrition Examination Surveys, which are annual government surveys that provide information on people's dietary intakes; the National Center for Health Statistics, for data on how many people died of certain diseases in a year; and findings from studies and clinical trials linking diet and disease. [7 Foods Your Heart Will Hate]

The researchers found that, in 2012, just over 700,000 people died from a cardiometabolic disease. Of these deaths, nearly 320,000 — or about 45 percent — could be linked to people's diets, according to the study, published today (March 7) in the journal JAMA.

The estimated number of deaths that were linked to not getting enough of certain healthier foods and nutrients was as least as substantial as the number of deaths that were linked to eating too much of certain unhealthy foods, according to the researchers, who were led by Renata Micha, a research assistant professor of nutrition and epidemiology at Tufts University in Boston.

In other words, Americans need to do both: Eat more healthy foods, and less unhealthy food.

The researchers focused their analysis on 10 food groups and nutrients: fruits, vegetables, nuts and seeds, whole grains, unprocessed red meat, processed meat, sugar-sweetened beverages, polyunsaturated fats, omega-3 fats from seafood, and salt, according to the study.

For each food or nutrient, the researchers identified an "optimal intake" amount. When people ate more or less than this optimal amount, the intake was considered suboptimal.

Overall, the greatest number of deaths were linked to suboptimal sodium intake; in other words, eating too much salt. The researchers' model found that about 66,500 cardiometabolic deaths in 2012 were linked to high sodium intake.

Not eating enough nuts and seeds was the dietary factor linked to the second highest number of deaths (59,000), followed by too much processed meat (58,000 deaths), too little omega-3 fats from seafood (55,000 deaths), too few vegetables (53,000 deaths), too few fruits (52,500 deaths) and too many sugar-sweetened beverages (52,000 deaths), according to the study.

When the researchers looked at specific demographic groups within the study, they found that more deaths in men were linked to dietary factors than in women. In addition, a greater number of deaths in younger people were linked to dietary factors, compared with older people. There was also a greater number of deaths linked to diet among African-Americans and Hispanics when compared with non-Hispanic whites. 

The researchers also calculated the percentage of deaths in 2002 that were linked with dietary factors, and found that deaths linked to certain dietary factors — such as too many sugar-sweetened beverages, not enough nuts and seeds and not enough polyunsaturated fats — decreased between 2002 and 2012. The number of deaths attributed to factors such as sodium and unprocessed red meats, however, increased over the same time.

Notes of caution

The findings have the potential to help guide public policy planning to prevent early deaths and reduce health disparities, according to an editorial that was published alongside the study in the same journal. The editorial was written by Noel Mueller, an assistant professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health, and Dr. Lawrence Appel, a professor of medicine at the same institution. [5 Diets That Fight Disease]

However, there are several limitations to consider, Mueller and Appel wrote. For example, the calculations that the researchers made in the new study assume that there is a cause-and-effect relationship between dietary factors and death, they wrote. However, the studies used in the model were observational studies, which don't prove cause-and-effect, they wrote.

In addition, Mueller and Appel noted that there may be other dietary factors beyond the 10 included that could play a role, such as saturated fat and added sugar. It's also possible that certain dietary factors are linked, such as sodium and processed meats, they wrote.

Despite the limitations, the study is "quite relevant to public health nutrition policy," Mueller and Appel wrote. As the study authors suggested, "policies that affect diet quality, not just quantity, are needed," they wrote.

Originally published on Live Science.

The human brain can produce the sugar fructose, a new small study finds.

Researchers found that the brain can convert one form of sugar, called glucose, into another form, called fructose. People who have too much fructose in their diet may face an increased risk of conditions such as type 2 diabetes and obesity.

Previous research has suggested that fructose and glucose act differently in the brain. For example, studies have shown that glucose sends signals of fullness to the brain, but fructose does not, lead study author Dr. Janice Hwang, an assistant professor of medicine at Yale University, said in a statement.

But although it was clear that fructose was found in the brain, a lingering question remained: How does the sugar get into the brain, particularly in high concentrations? [10 Things You Didn't Know About the Brain]

Earlier work showed that glucose enters the brain by crossing the blood-brain barrier, the researchers wrote in the study. And although fructose is also thought to be able to cross this barrier, the sugar is found in "exceedingly" low concentrations in the blood, because it is broken down by the liver, according to the study. This means that very little fructose would be available to cross into the brain.

In the new study, published today (Feb. 23) in the journal JCI Insight, eight healthy people had their brains scanned while they received intravenous infusions of glucose over a 4-hour period. The scans measured the levels of glucose and fructose in the participants' brains using a special type of imaging.

During the 4-hour period, the researchers also periodically took blood samples to measure the participants' blood glucose levels, and adjusted the infusions to make sure that the participants maintained a specific amount of sugar in the blood. In addition, separate blood samples were taken at five points during the experiment to measure the levels of fructose in the blood.

The researchers found that as glucose levels increased in both the blood and the brain, fructose levels in the brain also increased — but after a slight delay. For example, the researchers observed an increase in brain glucose levels 10 minutes into the experiment but did not see the increase in brain fructose levels until 20 minutes in. Fructose levels in the blood, however, didn't increase until much later in the experiment — 180 minutes in — and at that point, they rose only slightly, the researchers found.

The findings "show for the first time that fructose can be produced in the human brain," Hwang said. Previous studies have shown that fructose can be produced in animals' brains, she noted.

One way glucose is converted to fructose is through a series of chemical reactions called the polyol pathway, the researchers wrote in the study. These reactions, which convert glucose into another sugar called sorbitol, and then convert sorbitol into fructose, occur in tissues throughout the body, including the brain, they wrote. (During the experiment, the researchers also measured levels of sorbitol in the blood, and found that, as with fructose levels, they did not increase initially.)

The study suggests that fructose levels in the brain are not simply linked to the amount of fructose a person eats; rather, that fructose in the brain "can be generated from any sugar you eat," Hwang said. [5 Experts Answer: Is Diet Soda Bad For You?]

Dr. Kathleen Page, an endocrinologist and assistant professor of medicine at the University of Southern California Keck School of Medicine, who was not involved with the study, said that the findings are "intriguing" and, "if confirmed in future studies, could have important implications on the effects of sugar on brain function."

"The findings could provide new insights on how high blood glucose levels affect brain function," Page told Live Science. "This would be particularly relevant to patients with diabetes, whose blood glucose levels can fluctuate to the high levels achieved" in the study, she said.

Page noted, however, that the study was small, and that the researchers only indirectly measured fructose levels in the brain. 

Originally published on Live Science.

Coffee and tea drinkers who regularly sweeten and flavor their drinks with add-ins, such as sugar and milk, may be stirring in up to 69 extra calories a day, a new study finds.  

Coffee and tea are among the most popular drinks in the U.S., the researchers wrote in the study.

Although the drinks contain few to no calories on their own, many people flavor or sweeten these beverages: The researchers found that 68 percent of coffee drinkers and 33 percent of tea drinkers in the study reported consuming their drinks with caloric add-ins, according to the new study, published Jan. 30 in the journal Public Health.

Compared with those who took their coffee black, coffee drinkers who used add-ins drank 69 more calories each day, the researchers found. For tea drinkers, those who used add-ins consumed about 43 calories more each day, compared with those who didn't add anything to their tea, the researchers found. [11 Surprising Things That Can Make You Gain Weight]

The number of extra calories each day may seem small, but they can add up to extra pounds, lead study author Ruopeng An, an assistant professor in the department of kinesiology and community health at the University of Illinois at Urbana-Champaign, said in a statement.

"Our findings indicate that a lot of coffee and tea drinkers regularly use caloric add-ins to improve the flavor of their beverages, but possibly without fully realizing or taking into consideration its caloric and nutritional implications," An said.

In the study, the researchers looked at data from more than 13,000 coffee drinkers and more than 6,200 tea drinkers who took part in the National Health and Nutrition Examination Surveys (NHANES) from 2001 to 2012. The NHANES is a regularly conducted government survey that collects information on Americans' health and diet.

Sugar and sugar substitutes, cream and cream substitutes, half-and-half, and whole or reduced-fat milk were among the top add-ins for coffee drinkers, the researchers found. Tea drinkers were most likely to add sugar or sugar substitutes, honey and whole or reduced-fat milk, according to the study.

For both coffee and tea drinkers, the majority of added calories came from sugar, followed by fat, the researchers found. Of the 69 extra calories that coffee drinkers added, on average, 42 calories, or 60 percent, came from sugar, and 23 calories, or 33 percent, came from fat, according to the study. For tea drinkers, of the 43 extra calories that they added, on average, 37 calories, or 85 percent, came from sugar, and 3.7 calories, or 9 percent, came from fat, the researchers found.

The researchers noted that adding dairy to coffee and tea does contribute calcium to a person's diet. However, coffee drinkers added, on average, 22 milligrams of calcium, and tea drinkers added, on average, just 3 mg — representing a small step toward the daily recommended amount of calcium, which is about 1,000 mg. 

Originally published on Live Science.

Mary Tyler Moore's death on Wednesday at age 80 may highlight the long-term effects that type 1 diabetes can have on the body.

Moore died Jan. 25 after going into cardiopulmonary arrest, which means her heart stopped beating, several news outlets reported, citing Moore's publicist Mara Buxbaum. She had also recently contracted pneumonia. Moore had been diagnosed with type 1 diabetes when she was in her 30s.

With new advances in medicine, type 1 diabetes no longer means a certain premature death, but it still has a significant impact on the body over time. [Extending Life: 7 Ways to Live Past 100]

"The main way the body is affected is the chronic exposure to high blood sugar.  These high blood sugars damage various organs — in particular, the eyes, kidneys and nerves — to increase cardiovascular disease," said Dr. Robert Gabbay, the chief medical officer at the Joslin Diabetes Center in Boston, a nonprofit research institution affiliated with Harvard Medical School.

In people with type 1 diabetes, the pancreas has nearly completely stopped producing insulin, the hormone that allows the body cells to take in glucose and use it for energy. (This is a different condition from type 2 diabetes, which occurs when the body cannot produce enough insulin or use insulin effectively.) In those with type 1 diabetes, glucose instead builds up in the blood stream, and can cause fatigue, weakness, weight loss and excessive urination when untreated. Eventually, the disease can cause complications, including heart attack, strokes, blindness and kidney failure, according to the Joslin Diabetes Center.

But is it possible to die from complications of type 1 diabetes?

"Unfortunately, very much so," Gabbay told Live Science. "In the absence of insulin treatment, people with diabetes will die over time. Chronic exposure to high blood sugars can damage the heart and brain, leading to heart attack and strokes."

This is because glucose in the blood can damage blood vessels, leading to an elevated risk of heart disease, according to the Joslin Diabetes Center. Damaged blood vessels can also bring about long-term damage to the nerves and kidneys.

However, thanks to improved treatments, people with diabetes are living longer, Gabbay said. He noted that at the Joslin Diabetes Center, some people have lived with diabetes for 75 or more years. [5 Key Nutrients Women Need as They Age]

In fact, in a 2007 study published in the journal Diabetes Care, researchers analyzed data from more than 500 people with type 1 diabetes who had survived 50 years or more with the disease. Many of these people showed remarkably few complications: 40 percent did not have a serious eye disease even after 50 to 80 years of living with type 1 diabetes, and 66 percent still produced some insulin, suggesting that some people with type 1 diabetes may be able to produce insulin even 50 years after their initial diagnosis.

"The good news is that, with the right treatment and care, people with diabetes can live normal lives and much of the complications associated with diabetes can be prevented," Gabbay said.

Originally published on Live Science.

Soda habits among kids and adults in the U.S. are still going strong: About two-thirds of children and half of adults report drinking at one least one sugar-sweetened beverage a day, two new reports find.

One report focused on children and teens ages 2 to 19; it found that 63 percent of youth in the U.S. reported drinking at least one sugary drink a day from 2011 to 2014.

The other report focused on adults in the U.S.; it found that 49 percent said they drank at least one sugar-sweetened beverage a day during the same time period. Both reports were published today (Jan. 26) by the Centers for Disease Control and Prevention (CDC).

Previous studies have found that drinking sugary drinks is linked to health problems in both adults and children, including weight gain, type 2 diabetes and dental cavities, the researchers wrote.

The 2015-2020 Dietary Guidelines for Americans recommend that people cut the amount of added sugar in their diets to less than 10 percent of their total daily calories, and choose drinks with no added sugars. [How to Eat Healthy in 2017 (and Cut Sugar, Salt and Fat)]

The new findings showed that many people's sweetened-beverage consumption alone brings them close this amount of added sugar per day.

For example, among children, boys drank, on average, 164 calories' worth of sugar-sweetened beverages a day, which contributed to 7.3 percent of their total recommended daily calorie intake; girls drank, on average, 121 calories from sugary drinks, or 7.2 percent of their total recommended daily calorie intake, according to the children's report.

Adult men consumed, on average, slightly more calories from sugar-sweetened beverages a day than boys: 179 calories, or 6.9 percent of their total recommended daily caloric intake; women, however, consumed, on average, fewer calories from the drinks than girls: 113 calories or 6.1 percent of their daily recommended calories, according to the adults' report.

The researchers also found that among children, sugary drink intake increased with age: Teens ages 12 to 19 drank more sugar-sweetened beverages than children in the 2- to 5-year-old age group as well as kids in the 6- to 11-year-old group.

For adults, the researchers observed the opposite effect: Sugary drink intake decreased with age, with intake at its highest point for adults ages 20 to 39.

The researchers also noted that there were differences in sugar-sweetened beverage intake by race. [4 Tips for Kicking Your Soda Habit]

Among girls, non-Hispanic black girls consumed, on average, the highest number of calories from sugar-sweetened beverages each day, the researchers found. Among boys, non-Hispanic white, non-Hispanic black and Hispanic boys all consumed, on average, similar amounts of sugar-sweetened beverages, while non-Hispanic Asian boys consumed fewer calories on average each day from the drinks, according to the report.

For adult men, non-Hispanic black and Hispanic men had, on average, the highest daily intake of calories from sugar-sweetened beverages, according to the report. For women, non-Hispanic black women consumed the most calories from the drinks compared to other women, the researchers found.

The data used in the two reports came from two consecutive years of the National Health and Nutrition Examination Survey, 2011-2012 and 2013-2014.

Originally published on Live Science.

11 Ways Processed Food Is Different from Real Food

What exactly makes processed food unhealthy?

In a new editorial, published today (Jan. 23) in the journal JAMA Pediatrics, Dr. Robert Lustig, a pediatrician and longtime childhood-obesity researcher at the University of California, San Francisco, outlined 11 ways in which processed foods differ nutritionally from unprocessed foods.

Moreover, Lustig argued in the editorial, processed foods have harmed Americans in four areas: The foods have increased refined carbohydrate intake, increased rates of obesity and type 2 diabetes, harmed the environment, and driven Americans to spend more on health care, Lustig wrote. [10 Ways to Promote Kids' Healthy Eating Habits]

Processed foods are defined in terms of the food engineering that goes into making the products, Lustig wrote. A processed food meets the seven following criteria, the editorial said: The food is mass-produced, is consistent from batch to batch, is consistent from country to country, uses specialized ingredients, consists of prefrozen macronutrients, stays emulsified (meaning that its fat-based and water-based components stay mixed together, rather than separating), and has a long shelf or freezer life. 

But defining processed foods by these engineered properties doesn't reflect the vast nutritional differences between processed and unprocessed foods, Lustig wrote. Read on to learn about what makes processed food different. 

Not enough fiber

Compared with unprocessed food, processed food has too little fiber, Lustig wrote.

Fiber is important to health because it plays a key role in how food is absorbed in the gut. In the intestines, fiber forms a gelatinous barrier that coats the intestinal walls, according to the editorial.

This barrier slows the absorption of glucose and fructose into the blood, which helps prevent blood sugar levels from spiking. The slow absorption of food gives gut bacteria more time to feed on it, the editorial said. When gut bacteria break down food, the compounds they produce can benefit the body.

Not enough omega-3 fatty acids

Processed food contains too few omega-3 fatty acids, the editorial said.

The body converts these fatty acids, which are found in foods such as fish and nuts, into compounds called docosahexaenoic acid and eicosapentaenoic acid, both of which have anti-inflammatory properties, Lustig wrote. 

Too many omega-6 fatty acids

Conversely, processed foods contain too many omega-6 fatty acids, Lustig wrote.

These fatty acids, though similar to omega-3s, are converted in the body to a proinflammatory compound called arachidonic acid.

Lustig noted in the editorial that the ratio of omega-6 to omega-3 fatty acids in the diet should ideally be one to one; however, the typical U.S. diet has an omega-6 to omega-3 ratio of 25 to one, which favors a proinflammatory state. This inflammation can cause oxidative stress and damage to cells in the body, he wrote. 

Not enough micronutrients

Processed foods contain too few vitamins and minerals, known as micronutrients.

Many of these micronutrients, such as vitamins C and E, act as antioxidants, which help prevent cellular damage, Lustig wrote. 

Too many trans fats

Trans fats are another problem for processed foods, the editorial said.

Though the Food and Drug Administration has passed new regulations that require companies to remove trans fats from their foods by June 2018, the ingredients are still currently found in processed foods.

Trans fat molecules are structurally different from other types of fats, such as omega-3 and omega-6 fatty acids. Because of this difference — a double bond found in the molecule — the body is unable to break down trans fats, Lustig wrote.

Instead, the trans fats end up in a person's arteries and liver, where they generate damaging free radicals, he wrote. 

Too many branched-chain amino acids

Processed foods contain too many branched-chain amino acids, the editorial said.

Amino acids are the building blocks of proteins. The "branched-chain" in the name refers to the chemical structure of the amino acid. Several amino acids that the body needs, including valine, leucine and isoleucine, have branched chains, Lustig wrote.

And although branched-chain amino acids are needed for building muscle, when a person eats too many of them, the excess molecules go to the liver, where they are converted to fat, he wrote. 

Too many emulsifiers

Emulsifiers, which are compounds that help keep fat and water from separating in foods, are also found in high levels in processed foods, the editorial said.

These compounds act as detergents, however, and can strip away a type of mucus membrane that lines the intestines, protecting cells, Lustig wrote.

This can put people at risk for intestinal disease or food allergies, he wrote. 

Too many nitrates

Nitrates, which are found in products such as cured meat, are converted in the body to compounds called nitrosoureas, according to the editorial.

These compounds have been linked to colon cancer, Lustig wrote. 

Too much salt

Unsurprisingly, processed foods contain more salt than unprocessed foods, the editorial said.

Too much salt in the diet is linked to hypertension and heart disease, Lustig wrote. 

Too much ethanol

This distinction doesn't apply to all processed foods, but too much ethanol, or alcohol, is a concern for adults, Lustig noted.

Ethanol is converted in the body into liver fat and also plays a role in oxidative stress, he wrote. Drinking too much alcohol is linked to a number of diseases, including type 2 diabetes and nonalcoholic fatty liver disease, according to the editorial.

Too much fructose

Processed food contains high levels of fructose, Lustig wrote.

Fructose, which is a type of sugar, is broken down in the liver in the same way as ethanol, according to the editorial. Indeed, sugar is sometimes referred to as the "alcohol of the child," Lustig wrote.

Many children today now have diseases traditionally linked to alcohol consumption, such as fatty liver disease, even though these kids do not consume alcohol. This has been linked to their sugar consumption, Lustig wrote.

Originally published on Live Science.

Diet and Weight-Loss FIndings

Fat-filled diets and hunger-curbing injections may sound like fads, but in 2016, new research suggested that such interventions could have health and weight-loss benefits.

Here are seven studies from 2016 that highlight some of the most intriguing diet and weight-loss findings of the year

Dieting actually improves your mood.

Think you'll be "hangry" if you go on a diet? Think again: A study published in the journal JAMA Internal Medicine found that when people who were normal weight or overweight (but not obese) cut calories, they slept better, were in a better mood and had better sex lives.

In the study, researchers looked at 220 people who were divided into two groups: a calorie-restricted group advised to cut their daily calorie intake by about 25 percent, and a control group that received no dietary advice. Researchers tracked the participants for two years, asking them to periodically fill out questionnaires about their mood, quality of life, sexual function and sleep.

"We found that normal-weight and mildly overweight people who wish to lose weight need not worry about decreased quality of life," Corby Martin, director of the Ingestive Behavior Laboratory at the Pennington Biomedical Research Center in Louisiana and the lead author of the study, told Live Science in May.

Instead, "they can actually expect to feel better," Martin said. Another benefit? The participants in the calorie-restricted group lost an average of about 17 lbs. (8 kilograms) over the two-year period, compared with almost no weight change in the control group.

There could be an exercise "sweet spot" for losing weight.

What's the optimal amount of exercise to do if you want to lose weight? A study published in the journal Current Biology may provide some clues: Researchers found that people who engaged in moderate levels of physical activity burned about 200 more calories per day than those who had the lowest levels of physical activity. However, strikingly, the people who were the most physically active burned, on average, the same number of calories as those who were moderately active.

This may be because the body adapts to higher levels of activity, study author Herman Pontzer, an associate professor of anthropology at the City University of New York, told Live Science in January. Exercising a lot may actually prompt the body to make adjustments to adapt and actually keep its energy expenditure at the same level as it does when exercising less, the researchers concluded.

Injections of tiny beads could promote weight loss.

In a small study presented at the Society of Interventional Radiology's annual meeting this year, researchers described a new procedure that may curb feelings of hunger and promote weight loss.

In the procedure, called bariatric arterial embolization, microscopic beads are injected into the blood through a tiny nick in the wrist or groin. The beads travel to a part of the stomach called the fundus, where they decrease the amount of blood flow to that area. The fundus produces most of the body's ghrelin, also known as the hunger hormone, so by decreasing blood flow to the area, the procedure may limit the amount of ghrelin the fundus secretes, the researchers said.

Study lead author Dr. Clifford Weiss, director of interventional radiology research at the Johns Hopkins University School of Medicine, noted in a statement that the doctors who completed the study are excited about the possibilities the procedure offers. Compared to weight-loss surgery, this procedure "is significantly less invasive and has a much shorter recovery time," he said.


However, the findings have not yet been published in a peer-reviewed journal, and much more research will be needed to confirm the procedure's safety and effectiveness.

Eating fat doesn't make you fat.

A study published in the journal The Lancet Diabetes & Endocrinology found that men and women who followed a high-fat, Mediterranean diet that was rich in either olive oil or nuts lost more weight and reduced their waist circumference more than people who were instructed to reduce their fat intake.

In the study, researchers used data gathered over a five-year period on people in Spain, as part of a study that examined the effects of the Mediterranean diet on heart health. The study included almost 7,500 older adults who were instructed to follow one of three diets: a Mediterranean diet with at least 4 tablespoons of extra-virgin olive oil each day, a Mediterranean diet with at least three servings of nuts each week, or a control diet in which the participants were advised to generally avoid consuming fat.

After five years, the people in both the olive-oil group and the nut group lost more weight than the control group, and also greater reductions in their waist circumferences when compared with the control group.

The key takeaway is that neither fat-rich diet led to weight gain or increases in weight, lead study author Dr. Ramon Estruch, an internal medicine physician at the University of Barcelona in Spain, told Live Science in June.

Plant protein may keep you full longer than meat does.

A recent study published in the journal Food and Nutrition Research found that plant protein may be more effective than animal protein at making you feel full and helping you eat less at your next meal.

In the study, 43 young male participants ate one of three different breakfast meals, on three different days, each two weeks apart. The first was a high-protein meat patty with a potato mash, the second was a high-protein legume patty with a split-pea mash, and the third was a low-protein legume patty with a potato mash. (Legumes are a plant group that includes beans and lentils.)

The men reported feeling fuller after eating the high-protein legume-patty meal than they did after eating each of the other two meals.

In addition, the participants who consumed the high-protein legume patty consumed 12 to 13 percent fewer calories at lunch compared with when they had consumed either of the other two patties for breakfast, senior study author Anne Raben, a professor of obesity research at the University of Copenhagen, told Live Science in November. One reason for this may have been the higher amount of fiber in the high-protein legume patty, the researchers noted.

Probiotics help lower blood sugar levels.

Consuming probiotics may help decrease blood sugar levels, according to a small study from Canada.

In the study, some people who were following the DASH (Dietary Approaches to Stop Hypertension) diet, which is recommended for people with high blood pressure, were asked to eat probiotics as well. The people who consumed probiotics over the three-month study period had a larger average decrease in several measures of blood sugar levels than the group that only followed the DASH diet and did not take probiotics.

Although more research is needed, the findings suggest that adding probiotics to the DASH diet could help protect against diabetes, said the study's author, Arjun Pandey, a researcher at the Cambridge Cardiac Care Centre in Ontario.

One possible explanation for the findings may relate to a compound called butyrate, which is produced in the gut by certain bacteria and plays a role in insulin sensitivity, Pandey told Live Science in November. Increased levels of butyrate may lead to higher insulin sensitivity, thus leading body cells to absorb sugar from the blood more efficiently and, in turn, decrease blood sugar levels, he said.

The findings were presented at the American Heart Association's Scientific Sessions annual meeting in November and have not been published in a peer-reviewed journal.

Working out before breakfast may help you eat less.

If you're looking to lose weight, try working out before breakfast: A small study published in the Journal of Nutrition and Metabolism suggests that skipping breakfast before your workout may help you consume fewer calories throughout the day.

In the study, 12 physically active, young white males were assigned to one of two groups: One group was given oatmeal and orange juice for breakfast, and the other group was given no breakfast. At 10 a.m., the men ran on a treadmill for an hour. Then, the men were given food to take with them and were instructed to eat as much as they wanted for the rest of the day. The researchers measured the amount of food left over. After one week, the men repeated the experiment, but the groups were switched.

The researchers found that the men consumed many more calories overall on days when they ate breakfast before exercising: The participants consumed an average of 4,500 calories on days when they ate breakfast before exercising, but an average of only 3,600 calories on days when they fasted before exercising, the study's lead author, Jessica Bachman, an assistant professor of exercise science at the University of Scranton in Pennsylvania, told Live Science in October.

Most of these calories were consumed in the evening, Bachman added. However, the study looked at a very small, homogenous group, so the researchers cautioned that more studies are needed to confirm the findings and apply them to different groups of people.

Live Science is bringing our readers a monthly series on personal health goals, with tips and tricks for reaching those goals with advice we've gathered from the countless health experts we've interviewed. Each month, we'll focus on a different goal, and the goal for February is "Eat Better." Follow us on Facebook and Twitter to connect with other readers who are working toward these goals.

Jump to: January — Lose Weight | March — Start Exercising | April — Cope with Allergies | May — Protect Yourself from Sun and Heat | June — Stay in Shape Outdoors

It's not uncommon to feel as if you're drowning in a sea of diet advice: drink red wine for heart health; avoid bacon and processed meats; make sure your diet is filled with "superfoods."

But eating a healthy diet is actually quite simple, if you know what to look for. Live Science pulled together the best advice and the most relevant stories about nutrition so you can eat better this year.

Nutrition Guidelines

There is no single "perfect" healthy diet. But the U.S. government guidelines, which emphasize eating fruits, vegetables and whole grains and moving away from salt, added sugars and saturated fats, are a good place to start.

Here's what they say:

• ChooseMyPlate: Tools & Resources for Healthier Diet
• The Big Picture: What the New Diet Guidelines Mean for You       
• Hold the Sugar, US Nutrition Panel Recommends
• For First Time, US Dietary Guides May Boost Veggies Over Meat (Op-Ed)

Should You Go Vegetarian?

Are vegetarian diets really better for you? That may depend on what your goals are. But science shows that it is OK to have some meat in your diet — just don't go overboard.

More info:

• Meat May Not Be So Bad for You After All (But There's a Catch)  
• Vegetarian Diets Lower Blood Pressure Best
• Want to Live Longer? Eat a Plant-Based Diet
• 7 Tips for Moving Toward a More Plant-Based Diet          

Mediterranean Diet

When it comes to healthy diets, it's hard to find one with more accolades than the Mediterranean diet. Rich in fruits, vegetables, olive oil and fish, it has been linked in studies to numerous aspects of health, from the head to the heart.

More info:

• Mediterranean Diet: Foods, Benefits & Risks
• Mediterranean Diet May Reduce Breast Cancer Risks
• Mediterranean Diet May Be Good for Your Brain
• Women Could Lower Fracture Risk with Mediterranean Diet
• Mediterranean Diet Linked to Slower Aging
• Mediterranean Diet May Prevent Diabetes

Other Diet Options

If you're not mad about the Mediterranean diet, there are other healthy ways to go. The American Heart Association’s "DASH" diet, which stands for Dietary Approach to Stop Hypertension, is not only praised as a heart-healthy diet but also a good diet for people who want to lose weight. And the "Japanese diet," or the general way that people commonly eat in Japan, has been linked to longer life, one study has shown.

More info:

• 'Japanese Diet' Linked to Longer Life
• Diet and Weight Loss: The Best Ways to Eat
• What is the Paleo Diet?

The Low Down on Sugar

The tables have turned on the sweet stuff: Although it was once considered not especially harmful, a slew of research now shows that sugar — specifically, added sugar — is particularly damaging to a person's health. Too much sugar can raise a person's risk for both Type 2 diabetes and heart disease.

More info:

• How to Fight Sugar Cravings
• Why is Too Much Sugar Bad for You?
• Added Sugar May Boost Risk of Heart Disease, Death      
• Infographic: How Much Sugar Is in That?        
• The Science of Sugar: Is Corn Syrup the Same?             

The Low Down on Fat

Not all dietary fat is bad. Indeed, increasing evidence suggests that unsaturated fats can benefit health. However, trans fats have proved to be very damaging, leading the FDA in 2015 to ban them as an ingredient. 

More info:         

• What Is Saturated Fat?
• What Do Fats Do in the Body?
• Eating Healthy Fats May Reduce Deaths from Heart Disease
• Eating Fat Doesn't Make You Fat
• Infographic: Different Kinds of Fat
• Facts about Trans Fat

The Low Down on Salt

The body needs sodium – aka salt­ – in order to function. But too much of this mineral raises blood pressure, which can lead to a slew of heart problems, including heart disease. The salt you sprinkle on your dinner or add to a recipe isn't the main cause of sodium in your diet; rather, the majority of dietary sodium comes from processed foods.

More info:

• The Great Salt Debate: How Much Sodium Is Too Much for Your Diet?     
• New FDA Salt Targets: Which Foods Would Change Most?
• 6 Ways to Hold the Sodium

Natural, Organic, GMO: What Do Labels Mean and Do They Matter?

Reading food packaging can seem like doing a word search sometimes, but what do all the labels food manufacturers throw on your favorite snacks actually mean? Sometimes, a label doesn't quite mean what it says. For example, "reduced sodium" products can still have a good deal of sodium — this label just means it has 25 percent less than the "regular" version of the same product. And in other cases, like with the word "natural," it doesn't mean anything at all.

More info:

• Food Labels: Definition of Natural & Organic
• Eating Organic Produce Can Limit Pesticide Exposure
• Organic Meat May Have Higher Parasite Risk
• GMOs: Facts About Genetically Modified Foods

Easy Ways to Eat Healthy

For easy ways to choose healthy foods, check out Live Science's roundup of tips.

• 9 Snack Foods: Healthy or Not?
• 6 Easy Ways to Eat More Fruits and Vegetables
• 10 New Ways to Eat Well

Tech Tools to Eat Healthy

In today's digital world, there are plenty of tech tools to help you eat a healthy diet.

• 10 Best Diet & Nutrition Apps
• Healthy Eating Trick: Use Tech to Order Food
• 10 Best Food Scales

Originally published on Live Science.

Sweetening your beverage with real sugar, "fake" sugar or a "natural" no-calorie sweetener makes little difference in the overall calories you consume in a day, a small new study suggests.

In the study, 30 healthy men ages 21 to 50 each visited a clinic four times. Each time, they ate the same breakfast, followed by a beverage that contained one of four sweeteners: regular table sugar (sucrose), an artificial sweetener (aspartame), or a natural no-calorie sweetener made from either the stevia plant (rebaudioside A) or monk fruit (mogroside V).

Later, the men received lunch, and were told to eat until they were full. They then went home and used a food diary to keep track of the calories they ate for the rest of the day. [7 Biggest Diet Myths]

The researchers found that, regardless of the type of sweetener in the men's beverages at breakfast, the study participants consumed about the same number of calories by the end of the day (around 2,300 calories). That's because participates ate slightly more at lunchtime on the days they had the no-calorie beverages at breakfast, compared with the days when they had the sugar-sweetened beverages.

"The energy 'saved' from replacing sugar with non-nutritive sweetener was fully compensated for at subsequent meals in the current study," Siew Ling Tey, who was a study researcher and is at the Agency for Science, Technology and Research (A*STAR) in Singapore, said in a statement.

In addition, although participants experienced spikes in blood sugar levels shortly after consuming the real-sugar beverage at breakfast, they experienced an even larger spike in blood sugar levels after lunch on the days when they consumed the no-calorie beverages. This meant that overall blood-glucose levels averaged out to about the same for all groups during a 3-hour period before and after lunch, the study said.

The researchers noted that their study was small and that each sweetener was tested on only a single day. Longer-term studies are needed to determine the prolonged effects on people's body weight and blood sugar levels of consuming different types of sugar and sweeteners, the investigators said.

The study will be published in an upcoming issue of the International Journal of Obesity, and an early version of the paper was published online Tuesday (Dec. 13).

Original article on Live Science.

NEW ORLEANS — Moderate drinking may have positive effects on some aspects of heart health beyond those seen with light drinking, a new study from Australia finds.

The people in the study who drank 10 to 20 grams of alcohol per day were less likely to develop a condition called metabolic syndrome, which is linked with heart disease, compared with the people who drank less than 10 g of alcohol per day. In the U.S., a standard drink contains about 14 g of alcohol, according to the National Institute on Alcohol Abuse and Alcoholism.

Metabolic syndrome is a condition that is diagnosed when a person has at least three of these five risk factors for heart disease: high blood pressure, low levels of "good" cholesterol, high blood sugar, high triglycerides (a type of fat) and high waist circumference. The new findings were presented here Monday (Nov. 14) at the American Heart Association's Scientific Sessions annual meeting. [7 Ways Alcohol Affects Your Health]

Previous studies looking at the effects of alcohol on heart health have often compared people who drank moderately with people who abstained altogether, said Duc Du, a researcher at the Menzies Institute for Medical Research at the University of Tasmania and the lead author of the study.

It is possible that in those previous studies that compared moderate drinking to abstinence from alcohol, researchers may have overestimated the benefits of alcohol consumption, Du told Live Science.

In the new study, Du and his colleagues looked at the effects of different amounts of drinking on heart health compared with light drinking in a group of about 2,200 young adults. The average age of the participants was 29.5, according to the study.

The researchers found that 54 percent of the people in the study were considered light drinkers, meaning they drank, on average, less than 10 g of alcohol per day, and 13 percent were nondrinkers. They also found that 22 percent of the people in the study were moderate drinkers, meaning they drank, on average, between 10 g and 20 g of alcohol per day, Du said. Five percent of the people in the study were heavy drinkers, or those who drank, on average, between 20 g and 30 g of alcohol per day, and 6 percent were very heavy drinkers, who drank, on average, more than 30 g of alcohol per day.

Compared with light drinkers, moderate drinkers were less likely to have metabolic syndrome, the researchers found. There was no difference in the likelihood of having metabolic syndrome between heavy drinkers and light drinkers, or between nondrinkers and light drinkers, the researchers found. [

The researchers also looked to see if alcohol consumption was linked to any of the individual components of metabolic syndrome. [Raise Your Glass: 10 Intoxicating Beer Facts]

Compared to light drinkers, nondrinkers had higher waist circumferences, on average, and lower average levels of high-density lipoprotein cholesterol, which is considered the "good" type of cholesterol, according to the study. Moderate and heavy drinkers also had higher average levels of good cholesterol than light drinkers did, the researchers found.

Both heavy and very heavy drinking, however, were linked to significantly higher blood pressure measurements, on average, compared with light drinking, the researchers found.

The researchers noted that the links in the study held after they took into account the study participants' levels of physical activity, and whether they had depression. However, the findings do not prove there is a cause-and-effect relationship between moderate drinking and a lower risk of metabolic syndrome.

Overall, young adults should consider both the positive and negative effects of alcohol consumption when deciding whether to drink, the researchers concluded.

Originally published on Live Science.

NEW ORLEANS — The microbes that live in your gut may play a surprising role in your blood sugar levels, a small new study from Canada finds.

The study involved people who were following the DASH diet, which is recommended for people with high blood pressure. The people on this diet who also consumed probiotics, which are considered "good" bacteria, had a decrease in several measures of blood sugar levels over a three-month period, according to the findings. People with consistently high blood sugar levels may or may not go on to be diagnosed with diabetes; a diagnosis can depend on the results of several tests.

Although more research is needed, the findings suggest that adding probiotics to the DASH diet could be used in the future to help protect against diabetes, said Arjun Pandey, a researcher at the Cambridge Cardiac Care Centre in Ontario and the author of the study. [8 Tips to Be a Probiotic Pro]

Pandey presented his findings here on Sunday (Nov. 13) at the American Heart Association's Scientific Sessions annual meeting. The findings have not been published in a peer-reviewed journal.

In the study, 80 people with high blood pressure were placed on either the DASH diet or the DASH diet plus probiotic-rich foods. About 15 percent of the participants had prediabetes, Pandey noted, which means their blood sugar levels were elevated but were not considered high enough to warrant a diagnosis of diabetes.

The DASH diet, which stands for Dietary Approaches to Stop Hypertension, is one of the most effective non-drug-related methods for improving certain aspects of heart health, including lowering blood pressure, Pandey told Live Science.

The people in the study who added the probiotics to their diet did so by replacing certain components of the DASH diet with probiotic-rich components, Pandey said. For example, instead of just consuming any type of low-fat dairy product, as recommended by the DASH diet, a person could eat a low-fat probiotic yogurt, he said.

Before the study participants started the diets, the researchers measured the people's hemoglobin A1C, fasting blood sugar levels and blood pressure. They took the measurements again at the end of the study.

The hemoglobin A1C test measures how much hemoglobin, a protein found in red blood cells, is linked with sugar molecules, according to the American Diabetes Association (ADA). The more sugar molecules that are present in a person's blood, the more linked-up hemoglobin molecules there are, the ADA says. The fasting blood sugar test measures a person's blood sugar levels before he or she has eaten anything that day.

Before the diets began, there were no differences in the measurements between the two groups, Pandey said. [Don't Be Fooled: 5 Probiotics Myths]

After three months, both groups had similarly lower blood pressure measurements, Pandey said. In other words, adding probiotics did not appear to be associated with a change in blood pressure, specifically.

But adding probiotics did have a significant link with the participants' blood sugar measurements, Pandey said. 

At the three-month mark, the people who had followed only the DASH diet (with no added probiotics) had lowered their hemoglobin A1C, on average, by 3.4 percent. In comparison, those who had followed the DASH diet plus probiotics had lowered their hemoglobin A1C, on average, by 8.9 percent.

Adding probiotics to the DASH also had a stronger link with the participants' fasting blood sugar levels, according to the study. The DASH-plus-probiotics group lowered their fasting blood sugar levels by 10.7 percent, on average, compared with an average reduction of 3.3 percent in the group that followed only the DASH diet. 

Although the study doesn't prove a cause-and-effect link between probiotics and lower blood sugar levels, one possible explanation for how probiotics could lower blood sugar levels is through a compound called butyrate, Pandey said. In the gut, certain bacteria produce butyrate, which may play a role in insulin sensitivity, he said. When insulin sensitivity is higher, the body does a better job of absorbing sugar from the blood, therefore lowering blood sugar levels.

Pandey noted that there were several limitations to the study, including the small number of study participants and the short duration of the study. To validate the findings, the research should be carried out in a larger, more diverse group of people for a longer time period, Pandey said.

Originally published on Live Science.

People who don't get enough sleep drink more soda and energy drinks than those who get the recommended amount of sleep per night, a new study finds.

In the study, researchers analyzed information from nearly 19,000 U.S. adults who participated in a national health survey from 2005 to 2012, which included questions about diet and sleep habits.

People who said they generally slept 5 hours or less per night drank an average of 21 percent more sugar-sweetened beverages, including soda and energy drinks, than those who generally slept 7 to 8 hours per night, the study found.

"We think there may be a positive feedback loop, where sugary drinks and [loss of sleep] reinforce one another, making it harder for people to eliminate their unhealthy sugar habit," study co-author Aric Prather, an assistant professor of psychiatry at the University of California, San Francisco, said in a statement.

In particular, those who slept less drank more caffeinated sugary drinks, the researchers found. The participants who usually slept 5 hours or less per night consumed 33 percent more caffeinated sodas and sugary energy drinks than those who got the recommended amount of sleep. People in the study consumed about the same amount of decaffeinated sodas, regardless of how much they slept, the researchers found.

The researchers noted that because the study was conducted at a single point in time, they can't tell whether sugary caffeinated drinks actually cause people to sleep less or whether people who don't get enough sleep are turning to sugar and caffeine to stay alert. But the researchers said it's possible that both are true, and that some people get caught in a vicious cycle in which their sleep habits affect their beverage choices and their beverage choices affect their sleep. [10 Interesting Facts About Caffeine]

"This data suggests that improving people's sleep could potentially help them break out of the cycle and cut down on their sugar intake," Prather said.

The findings held even after the researchers took into account factors that could affect how much people slept or their consumption of sugar-sweetened beverages, including their age, household income, marital status, physical activity levels and whether they had been diagnosed with a sleep disorder.

There was no link between how long people slept and their consumption of juice, tea or diet drinks, the researchers said.

It's important to note that the participants in the study reported their own sleep habits, and it's possible that some people did not report their sleep accurately. Future studies could assess people's sleep habits objectively, with either a device that records brain waves or a wearable sleep monitor, Prather said.

Future studies also need to follow people over time to see how people's sleep habits and beverage consumption affect each other, Prather said.

The study is published online today (Nov. 9) in the journal Sleep Health.

Original article on Live Science.

Health Myths

Despite what you may have heard, drinking eight glasses of water a day isn't the key to good health. Also, neglecting to wear a coat on a cold day won't make you sick. And — you might want to sit down for this — pregnancy doesn't last nine months.

Health-related myths are often repeated as fact, even though any diligent Google search will reveal the truth behind these fallacies. Here are 26 of the most common medical myths, debunked.

Myth: Vaccines can cause the flu (and autism).

Although the body can develop a low-grade fever in response to any vaccine, rumors that a flu shot can cause the flu are "an outright lie," said Dr. Rachel Vreeman, co-author of "Don't Swallow Your Gum! Myths, Half-Truths, and Outright Lies about Your Body and Health" (St. Martin's Griffin, 2009).

The flu shot does contain dead flu viruses, but they are, well, dead. "A dead virus cannot be resurrected to cause the flu," Vreeman told Live Science in 2010. As for vaccines causing autism, this myth was started in 1998with an article in the journal The Lancet. In the study, the parents of eight (yes, only eight) children with autism said they believed their children acquired the condition after they received a vaccination against measles, mumps and rubella (the MMR vaccine). Since then, rumors have run rampant despite the results of many studies. For example, a 2002 study in The New England Journal of Medicine of 530,000 (yes, a whopping 530,000) children found no link between vaccinations and the risk of a child developing autism.

Unfortunately, the endurance of this myth continues to eat up time and funding dollars that could be used to make advances in autism, rather than proving, over and over again, that vaccinations do not cause the condition, said Vreeman, who also researches pediatric conditions.

Myth: Supplements always make you healthier.

Vitamin supplements may be not only ineffectual but even dangerous, studies have shown. For example, a study published in 2016 showed that some older women who take calcium supplements may face an increased risk of dementia. And in a huge review of 20 years of supplement research published in 2015, researchers found that taking high doses of vitamins may be linked with an increased risk of cancer.

Aside from these possible long-term risks, reports have suggested that supplements can cause damage in the short term too. A report published in 2016 found that a man in Pennsylvania who took Ayurvedic herbal supplement developed lead poisoning. Another report, also published in 2016, showed that a 4-year-old boy in England went to the ER after taking a slew of "natural" supplements, and developing a condition called vitamin D toxicity.

"The FDA does not require supplements to be regulated in the same way that drugs are, which can be a real problem," Vreeman said in 2010. As a result, the safety of many supplements has not been rigorously studied. Furthermore, supplement bottles can sport unsubstantiated claims and even make errors in dosage recommendations, she said.

It's a better idea to get your vitamins and other nutrients from eating real food, rather than taking a pill, she said.

"A vitamin pill is not the answer," Vreeman said. "Eating more healthily in general is the answer."

Myth: Cold weather makes you sick.

"This myth is common around the world, but it is just not true," Vreeman told Live Science. Studies have shown we may feel more cold symptoms — real or imaginary — when we are chilled (after all, a cold is called a "cold" for a reason), but the temperature itself does not make us more susceptible to viruses. This has been known since at least 1968, when a study in The New England Journal of Medicine showed what happened when researchers exposed chilly people to the rhinovirus (one cause of the common cold).

It turned out that whether they were shivering in a frigid room or in an icy bath, people were no more likely to get sick after sniffing cold germs than they were at more comfortable temperatures.

Vreeman said that cold air also does not make a difference in people's recovery time from a cold. In fact, although the research is in its early stages, "it is possible that being exposed to cold may even help your body in some way," she said.

However, its unclear how chilly conditions might affect the germs themselves. Research has shown that two common causes of colds — rhinoviruses and coronaviruses — may thrive at colder temperatures, and that the flu may spread most effectively under cold, dry conditions.

Some scientists speculate that colds are more common in cooler months because people stay indoors more, interacting more closely with one another and giving germs more opportunities to spread.

Myth: We use only 10 percent of our brains.

Motivational speakers and other self-help gurus have been promoting this one since as early as 1907, as a way to encourage people to tap into some latent capacity, explained Vreeman and the co-author of her book, Dr. Aaron Carroll, both of the Indiana University School of Medicine, write in the book. But these people were not basing the proclamation on sound science.

Today, scientists can look at any brain scan, measuring activity at any given time, and have a big laugh at this myth. "You just don't see big dormant areas," Vreeman said. The idea lingers in popular culture because "we want to think we haven't reached our full potential," Vreeman said.

Myth: Sugar turns kids into little monsters.

It can be hard to find a parent who does not believe this, Vreeman said. "But it is in their heads." In one particularly clever study among a slew of studies finding sugar's nil effect on unruliness, kids were given Kool-Aid sweetened with aspartame, a compound that contains no sugar. Researchers told half of the parents the Kool-Aid contained sugar, and told the other half the truth.

The parents in the study who thought their kids were riding a sugar high reported their children were uncontrollable and overactive. But a sensor on the kids' wrists that measured activity level said the opposite: The kids were actually acting subdued. The study was published in the Journal of Abnormal Child Psychology in 1994.

Sugar is often given at times when the rules are loosened and there are lots of other kids around, like birthday parties and holidays, Carroll told Live Science. These factors may be behind the myth's persistence in popular culture, he said.

Myth: You need to stay awake if you've had a concussion.

Anyone who may have a concussion should seek medical attention, but the condition is rarely severe or life-threatening. Warnings that people need to stay awake after incurring a concussion  most likely grew out of a misunderstanding about a particular type of head injury — one that involves brain bleeding and that causes people to have a "lucid period," followed by a coma or even death. But this is very uncommon and doesn't pertain to people with normal concussions, Vreeman said.

"If you've been evaluated by a doctor, and he has said that you have a mild regular concussion, you don't need to worry that someone has to wake you up every hour," she said.

Myth: Chewing gum stays in your stomach for 7 years.

Although it is true that many of the ingredients in gum — such as elastomers, resins and waxes — are indigestible, that does not mean they hang out in your guts for seven years. Plenty of what you eat — even things you are recommended to eat, such as fiber — is indigestible. But the digestive system is a robust piece of organic machinery, and anything it can't absorb, it moves along. Despite the stickiness and strange consistency of gum, "it passes right through your digestive tract and into the toilet," Vreeman explained.

Myth: Reading in the dark or sitting too close to the TV ruins your eyesight.

Dim light — or alternatively, staring into the multicolored tube at close range — can undoubtedly make your eyes work so hard they hurt. But there is no evidence that these practices cause long-term damage, Vreeman said. The TV myth may have started in the 1960s, and at that time, it may have been true. Some early color TV sets emitted high amounts of radiation that could have caused eye damage, but this problem has long been remedied, and today's TV and computer monitors are relatively safe, she said.

If you or your child tend to sit so close to the computer or TV that it hurts the eyes, it may be a good idea to get checked for nearsightedness. However, sitting too close does not create a need for glasses even if getting glasses can remedy the habit.

Myth: You should drink at least 8 glasses of water a day.

"In general, we are not all walking around in a dehydrated state," Vreeman said, adding that our bodies are very good at regulating our fluid levels. The eight-glasses-a-day myth likely started in 1945, when the Food and Nutrition Board of the National Research Council said adults should take in about 2.5 liters of water a day (equivalent to about eight glasses, or two-thirds of a gallon). Although most media outlets reported that as fact and stopped there, the council actually went on to explain that most of the 2.5 liters comes from food. According to Vreeman, the recommendation should be amended to the following: Drink or eat about eight glasses of fluid a day.

Myth: You should wait an hour after eating before you go swimming.

This myth has ruined many summer afternoons, forcing young and old to swelter in the heat while cool waters beckoned, all because they were careless enough to down a PB&J. Let the ban be lifted: There is no special reason not to swim after eating, Vreeman said.

It's true that any type of vigorous exercise can be uncomfortable (although not dangerous) after an overwhelming feast. But for most of us whose waterfront dining experience includes sand-dusted chips and soggy sandwiches, that is hardly a concern. And cramps can happen anytime, whether you've eaten or not. If you are swimming in waters so rough that a charley horse will mean the death of you, you should probably swim elsewhere. Just don't forget the picnic!

Myth: Fingernails and hair continue to grow after death.

This myth is actually just a misperception, and for many years, most physicians couldn't disprove it, even though they couldn't quite explain it. Here's what really happens to your nails and hair after you die: 

"As the body's skin is drying out, soft tissue, especially skin, is retracting," Vreeman said. "The nails appear much more prominent as the skin dries out. The same is true, but less obvious, with hair. As the skin is shrinking back, the hair looks more prominent or sticks up a bit."

Myth: Shaved hair grows back faster, coarser and darker.

Here's a myth you can debunk yourself by paying attention to your own hair after shaving. You may notice that new hair grows in with a blunt edge on top. Over time, that blunt edge gets worn down, making it seem thicker than it really is. But why might recently shaved hairs seem darker than their nonshaved counterparts? It could be that those newly spouted hairs haven't yet been bleached by the sun, Vreeman said.

But if you don't trust your own experimental skills, there's other evidence that this myth isn't reality. A clinical trial conducted in 1928 compared hair growth  in shaved patches to hair growth in nonshaved patches. The study found that new hair that replaced shaved hair wasn't darker or thicker, nor did it grow faster. More recent studies  have confirmed that one.

Myth: Eating turkey makes you drowsy.

Your excuse for taking a nap after dinner on Thanksgiving just went out the window. While turkey does contain a chemical called tryptophan that is known to cause drowsiness, your serving of Thanksgiving bird doesn't contain any more of the chemical than a similar-size serving of chicken or beef, Martha Stipanuk, a professor of molecular nutrition at Cornell University, told NPR in 2008.

So why do people feel so sleepy after a Thanksgiving feast? It could be the overall quantity of food you eat on this holiday that makes you drowsy. Those heaping mounds of carbohydrates on your plate (think dinner rolls and mashed potatoes), plus a few alcoholic beverages, will almost certainly make you feel tired, according to experts.

Myth: Ulcers are caused by spicy food and stress.

If you think your ulcers are acting up because of the curry you ate last night for dinner, think again. Although doctors once believed that ulcers were caused by stress, lifestyle choices or spicy foods, they now know that most ulcers are actually caused by the bacterium Helicobacter pylori.

Ulcers — sores that develop in the lining of the esophagus, stomach or the first part of the small intestine — can also be caused by certain medicines. Aspirin and iron tablets are the most common culprits, according to Dr. Arun Swaminath, director of the Inflammatory Bowel Disease Program at Lenox Hill Hospital in New York City. 

Myth: A woman can't get pregnant during her period.

Although it's unlikely that a woman will conceive during menstruation, it isn't impossible, according to Carroll. Sperm can live inside a woman's body for up to a week, and ovulation can occur soon after (or even during) the "bleeding" phase of a woman's menstrual cycle. That makes it possible for a woman to become pregnant if she has sex either during her period or shortly after it ends. 

Myth: You lose most of your body heat through your head.

Don't believe the hat salesman: You don't lose most of your body heat through your head.

In 2006, scientists decided to debunk this myth  once and for all. They found that the amount of body heat lost through a person's head is only about 7 to 10 percent of total body heat. In other words, body heat loss from the head is proportional to the amount of skin on the average human head.

Myth: Going out in the cold with wet hair will make you sick.

Don't have time to dry your hair before leaving the house on a cold day? Don't worry about it! Though lots of people might tell you that a wet head, plus cold air, is bound to equal a head cold, that's simply not the case, according to Weiss. Germs such as viruses and bacteria, not temperature changes, make people sick. So although you might be a bit chilly if you leave home with wet hair on a winter day, that doesn't mean you'll get sick, he said.

However, a study published in 2015 in the journal Proceeding of the National Academy of Sciences does suggest that rhinoviruses (the viruses behind the common cold) may take advantage of cold weather. Researchers found that cold temperatures might make it easier for these cold-causing viruses to replicate by diminishing the body's antiviral immune responses.

Myth: Deaths by suicide increase over the holidays.

Here's a myth you've probably heard every December: The number of people who die by suicide increases during the holiday season. But that's actually not the case. In fact, suicide rates in the U.S. are lowest in December, according to the Centers for Disease Control and Prevention's (CDC) National Center for Health Statistics.

One reason for this myth may be the way the media covers deaths from suicide. A recent analysis of media reports written during the 2013 holiday season found that 70 percent of published articles perpetuated this myth.

The number for the national suicide hotline is 800-273-8255.

Myth: Poinsettias are toxic.

Poinsettias aren't toxic. We repeat: Those beautiful flowers you've been so wary of keeping in your home during the holidays (lest they poison pets or children) are not toxic.

The plants can make people sick, but there have been no definitive cases of a person dying from exposure to a poinsettia plant.In a paper  published in the Southern Medical Journal in 1996, researchers reviewed 22,793 cases of poinsettia exposure that were reported to poison control centers over a seven-year period. They found that not one of those cases was fatal. The most severe reactions reported were stomachaches and cramping.

The myth about poinsettias being toxic may have come from a case, reported in 1919, of a 2-year-old in Hawaii who allegedly died after ingesting parts of the plant, according to a 2012 article in the Western Journal of Emergency Medicine. But the child's death was never confirmed, nor was the cause of death.

Myth: Chicken noodle soup cures … everything.

p> Everybody's heard that chicken soup is supposedly the best cure for whatever ails you. But does this delicious food really help you get better when you're sick?

Unfortunately, no, Weiss said. The combination of hot broth and yummy veggies is more of a comfort than a cure, he said. However, some research suggests that chicken noodle soup may work well as a placebo. In other words, it may convince you that you're getting better. So keep slurping!

Myth: Eating at night makes you fat.

Don't feel guilty the next time you reach into the fridge for a midnight snack.

Though eating late at night has been associated with obesity, this eating behavior doesn't actually cause obesity.

"You shouldn't be afraid to have that midnight snack anymore than a mid-day or mid-morning snack," Carroll said.

Myth: Psychiatric and emergency room visits increase during the full moon.

Myths about the moon's effect on human behavior have been around since at least the Middle Ages, but science doesn't support full-moon folklore. For example, one popular myth states that emergency psychiatric visits increase around the full moon. But that's just not the case.

A2005 study by Mayo Clinic researchers looked at how many patients checked into a psychiatric emergency department between 6 p.m. and 6 a.m. over several years. The researchers found no statistical difference in the number of emergency psychiatric visits on the three nights surrounding full moons versus other nights of the lunar cycle.

And regular emergency-room visits are not any more common during a full moon, either. In 1996, researchers at Northwestern University examined 150,999 records of emergency-room visits to a suburban hospital. Their study found no significant difference between the number of visits during the full moon versus other nights.

Myth: Taking probiotics helps prevent colds.

Sure, probiotics won't make you sick, but they won't keep you from catching a cold, either, according to Dr. Patricia Hibberd, a professor of pediatrics and chief of global health at MassGeneral Hospital for Children in Boston.

Although preliminary research does suggest that probiotics could possibly help ward off colds, no high-quality trials support this claim, Hibberd told Live Science in 2014. 

Myth: Babies get fevers when they are teething.

This is one of those myths that every parent has heard: Babies get fevers when they teethe. But this medical myth is both false and potentially dangerous, according to Vreeman. Parents shouldn't write off a baby's fever as due to teething, she warned.

Research has not shown a strong relationship between teething and high body temperatures, so if your tot has a fever, it might be time to visit the doctor.

Myth: Pregnancy lasts nine months.

Everyone knows that pregnancy lasts nine months. But everyone is wrong about this "fact."

"It's actually more like nine and a half months," said Dr. Joanne Stone, an obstetrician at Mount Sinai School of Medicine in New York City and co-author of "Pregnancy for Dummies" (For Dummies, 2009).

Doctors typically measure a full-term pregnancy as lasting 40 weeks, counting from the first day of a woman's last period. But women usually become fertile 10 to 16 days after their period starts. So by this method of counting, the first two weeks of most pregnancies actually take place before a woman has conceived. And just to confuse the matter even more, researchers have found that the amount of time a healthy pregnancy lasts can vary by as much as five weeks. 

Original on Live Science.

Depression during and after pregnancy may be linked to gestational diabetes, a new government study found. 

Women in the study who reported feeling depressed early in pregnancy were more likely to develop gestational diabetes later in pregnancy compared with those who did not report depression early in pregnancy, according to the study, from researchers at the National Institute of Child Health and Human Development (NICHD).

The findings suggest that "depression and gestational diabetes may occur together," Stefanie Hinkle, a population health researcher at the NICHD and the lead author of the study, said in a statement. [9 Uncommon Conditions That Pregnancy May Bring]

In addition, the researchers found that having gestational diabetes may increase women's risk for developing depression after pregnancy: Women in the study who had gestational diabetes were more likely to develop postpartum depression compared with those who did not have gestational diabetes, according to the study.

Gestational diabetes is a type of diabetes that occurs during pregnancy. When a person has diabetes, the body cannot properly control blood -sugar levels. During pregnancy, diabetes can put both the mother and the baby at risk; women can develop a high blood-pressure condition called preeclampsia, which can become life-threatening, and babies can grow too large within the uterus, which can make birth difficult.

In the U.S., 9.2 percent of women develop gestational diabetes, and postpartum depression affects 10 to 15 percent of mothers within a year of giving birth, according to the Centers for Disease Control and Prevention.

In the study, the researchers looked at data from about 2,800 women who were enrolled in the NICHD Fetal Growth Studies-Singleton Cohort, a long-term study that tracked women's health and the health of their babies, during and after pregnancy.

The women in the study filled out questionnaires in the first and second trimesters of pregnancy and at six weeks postpartum, indicating if they had any symptoms of depression. Based on these responses, the researchers calculated each woman's "depression score." In addition, the researchers reviewed the women's medical records to see if they had gestational diabetes.

Results showed that women with the highest depression scores in the first and second trimesters were three times more likely to have gestational diabetes than those women with lower depression scores.

In addition, women who had gestational diabetes were four times more likely to go on to develop postpartum depression compared with women who didn't have gestational diabetes, the researchers found.

The researchers noted that more research is needed to firmly establish the link between depression and gestational diabetes. The findings did not prove cause and effect, Hinkle said. However, previous studies have suggested that depression may have an effect on how the body breaks down sugar, which could lead to higher blood-sugar levels.

Until there's more information, doctors may want to keep an eye out for signs of gestational diabetes in pregnant women who have symptoms of depression, Hinkle said. "They may also want to monitor women who have had gestational diabetes for signs of postpartum depression," she added.

The study was published today (Sept. 19) in the journal Diabetologia. 

Originally published on Live Science.

People who smoke marijuana daily may be slimmer than those who don't use the drug, a new study suggests.

Researchers found that people in the study who used marijuana daily had about a 3 percent lower BMI (body mass index), on average, than those who did not use marijuana at all.

"There is a popular belief that people who consume marijuana have the munchies, and so [they] are going to eat a lot and gain weight, and we found that it is not necessarily the case," said lead study author Isabelle C. Beulaygue, a research support specialist in interventional radiology at the University of Miami. [Marijuana Could Treat These 5 Conditions]

In the study, the researchers looked at more than 13,000 adults ages 18 to 26. The researchers collected body measurements to calculate the participants' BMIs, and tested the participants for marijuana use. Six years later, when the participants were between ages 24 and 32, the researchers looked again at their marijuana use and BMIs.

The researchers found that the BMIs of women who smoked marijuana daily during the study were 3.1 percent lower than the BMIs of women who did not smoke marijuana daily during the study period. And the BMIs of men who smoked marijuana daily were 2.7 percent lower than the BMIs of those who did not smoke marijuana, according to the study, published in September in The Journal of Mental Health Policy and Economics.

Previous research on marijuana use and weight had yielded mixed results, the researchers said. For example, in one small study, researchers invited six people to their lab for 13 days. During the first half of the study, the researchers gave the people two to three placebo cigarettes per day, and during the second half, they gave them two to three marijuana joints per day. During the second half of the study, when the participantswere smoking marijuana, they consumed 40 percent more calories than they did during the first half, when they were smoking the placebo cigarettes.

Moreover, the participants gained 6.6 lbs. (3 kilograms), on average, during the second half of the study, according to the study, published in the journal Appetite in 1988.

However, a more recent review, published in 2014 in the journal Innovations in Clinical Neuroscience, suggested a link between marijuana use and lower BMI, which is in line with the new findings. [11 Odd Facts About Marijuana]

One of the strengths of the new study was that the researchers controlled for various factors of a person's lifestyle that can normally affect people's weight, such as their diet, exercise and alcohol consumption, according to the study. Even after the researchers took these factors into consideration, the link between marijuana use and lower BMI held, the researchers said.

Beulaygue said that the researchers are not advocating for marijuana as a new weight loss tool. Previous research has linked marijuana use to potential health effects on the brain and the heart.

Moreover, the new study does not prove that smoking marijuana causes people to lose weight or helps them to avoid gaining weight. Rather, it merely shows that there is a link between marijuana use and lower BMI, Beulaygue told Live Science.

The researchers said they don't know for sure what mechanism may explain this link. However, previous research has suggested that people who use marijuana regularly may break down blood sugar more quickly, which, in turn, may help to prevent weight gain, the researchers said.

Originally published on Live Science.

The sugar industry may have attempted to bias heart disease research in self-serving ways, downplaying studies that implicated sugar consumption in heart disease, and instead placing the blame on fats, a new study said.

In the study, researchers looked at correspondence that happened between the leaders of a sugar trade organization and heart disease researchers. The investigators also looked at internal sugar-industry documents and other materials.

The study focused on the circumstances surrounding the publication of a 1967 review article about the influences of dietary sugar and fat on coronary heart disease (CHD), which is caused by the narrowing of the arteries supplying blood to the heart.

That influential article "singled out fat and cholesterol as the dietary causes of CHD and downplayed evidence that sucrose consumption was also a risk factor," the researchers at the University of California, San Francisco, wrote in the new study, which appears today (Sept. 12) in the journal JAMA Internal Medicine.

But in the new study, the researchers "have produced compelling evidence that a sugar trade association not only paid for but also initiated and influenced research expressly to exonerate sugar as a major risk factor for coronary heart disease (CHD)," New York University nutrition and public health professor Marion Nestle wrote in an editorial accompanying the new findings in the journal. [10 Amazing Facts About Your Heart]

The Sugar Association, the trade organization in question, did not respond to requests for comment from Live Science. The Sugar Association evolved from the Sugar Research Foundation (SRF), which was the trade organization involved in the correspondences from the 1960s that were detailed in the new study, the study authors said.

Two theories of heart disease

In the 1950s, there were two competing ideas about which dietary factors increased people's risk of coronary heart disease: Some researchers suggested that fat and cholesterol led to CHD, but others, particularly British physiologist John Yudkin, blamed sugar, the new study said.

In 1964, John Hickson, who was then the vice president and director of research for the SRF, mentioned Yudkin's research in an internal memo. Hickson recommended that the trade organization fund CHD research. "Then we can publish the data and refute our detractors," Hickson wrote in the memo, the authors of the new study said.

In 1965, the trade organization paid two Harvard researchers to conduct a literature review focusing on papers that had claimed that sucrose and fructose have "some special metabolic peril," the new study said.

"This is a very common practice in industry-funded research. Instead of actually producing new research, they will pay scientists to review the existing literature and come out with the kinds of conclusions they want," Laura Schmidt, a professor of health policy at UCSF and an author of the new study, told Live Science. [Special Report: The Science of Weight Loss]

In the two-part review, which was published in 1967 in the New England Journal of Medicine (part one, published July 27; part two, published Aug. 3), the researchers looked at whether a high-sucrose diet could lead to CHD. They also looked at which interventions would be more effective in preventing CHD: modifying sucrose or modifying saturated fat levels in the diet, the authors wrote.

The review concluded that the only dietary changes needed to prevent CHD were cholesterol reductions and the substitution of polyunsaturated for saturated fats, the authors of the new study wrote.

But that review used different standards to evaluate studies on sugar than those used to evaluate the studies on fat, biasing the findings in favor of sugar, Schmidt told Live Science. Further, though other funding sources were mentioned in the paper, the funding from the sugar industry was not disclosed, the authors of the new study wrote.

"We can only imagine that they didn't [disclose sugar industry funding] because it was a biased review and they didn't want anybody to know why," Schmidt said.

But the researchers of the new study said that the bias they found in that 1967 review "demonstrates that the sugar industry was … trying to push the scientific debate in directions that would deflect attention from the role of sugar in heart disease," Schmidt said. [Why Is Too Much Sugar Bad for You?]

Sugar's role in heart disease

Since then, studies have shown that consuming added sugar does in fact promote cardiovascular disease, Kimber Stanhope, a nutrition researcher at University of California, Davis, who consulted with the authors on the new study told Live Science.

For example, a 2014 study found a correlation between the percentage of calories in people's diets that came from added sugar and their risk of dying from cardiovascular disease, Stanhope said. And a 2015 study, which Stanhope led, found that supplementing young adults' diets with drinks sweetened with high-fructose corn syrup led to increased levels of cardiovascular risk factors in the blood, she said.

"Over the past 10 years, in particular, researchers have been very very aggressively studying sugar's role in metabolic diseases, including heart disease, and demonstrating what we should have been studying in 1965, when this whole thing started," Schmidt said.

Original article on Live Science.

Kids in the United States are sweet on sugar, but a major health organization is issuing new guidelines to curb children's consumption of sugary foods and beverages.

In the first of three new recommendations from the American Heart Association (AHA), a panel of health and nutrition experts suggested that children ages 2 to 18 consume no more than 6 teaspoons (30 milliliters) of added sugar a day, according to the organization's statement published today (Aug. 22) in the journal Circulation.

That amount of sugar is equal to about 100 calories, or 25 grams (0.9 ounces) of sugar.

Added sugar is considered to be any sweetener that has calories — such as table sugar, high-fructose corn syrup, honey and molasses — and is used as an ingredient in processing and preparing foods or beverages. Added sugar also includes any sugars a person adds to food or drinks at a meal. [Why Is Too Much Sugar Bad for You?]

"There is little room in a child's diet for added sugars, because they need calories from vegetables, fruits, protein sources, whole grains and dairy to grow up healthy," said Dr. Miriam Vos, the chairperson of the committee that wrote the scientific statement, and an associate professor of pediatrics at Emory University School of Medicine in Atlanta.

Added sugar can, however, be used in small amounts to improve the taste of foods that are healthy and rich in nutrition — such as whole-grain cereals, flavored milk or yogurt — to make these foods more appealing for children, she said.

But there are loads of added sugar in sugary drinks, cookies, cakes and candies, foods which have little to no nutrition value, Vos said.

Three new recommendations

Kids ages 2 to 18 typically take in two to three times the amount of sugar recommended by the new guidelines, or about 13 teaspoons on average of added sugar a day for young children, and up to about 22 teaspoons on average a day for teens, according to the most recent data from the National Health and Nutrition Examination Surveyon the diets of American children. Moreover, even this estimate may be on the low side, because participants in dietary surveys tend to under-report their actual consumption, the scientific statement said. [Infographic: Grams of Added Sugar in Popular Foods and Drinks]

This is the first time the AHA has released its own set of recommendations for kids about added sugars. But previously, the federal government's 2015 Dietary Guidelines for Americansrecommended that children get no more than 10 percent of their total calories a day from added sugar, Vos said.

Estimating 10 percent of calories may be difficult for most parents, though, because they often don't know how many calories their children eat in a day, Vos told Live Science. To simplify this for parents, the new report set a single target of 100 calories daily of added sugar, an amount that is easy for parents to understand and is healthy for all children in the 2 to 18 age range, she said.

To reach their conclusions, the expert panel reviewed the scientific evidence on added sugars and heart health in children. The experts considered how added sugar in the diet affects a child's or teen's risk for obesity, high blood pressure, diabetes, and abnormal cholesterol or triglyceride levels.

The second recommendation from the AHA scientific report advised that children under age 2 have no added sugar in their diets. The panels of experts suggested that introducing added sugars in the diets of infants and toddlers may encourage them to develop a preference for sweets from an early age.

The third AHA recommendation called for children and teens to limit the amount of sugar-sweetened beverages they drink to no more than one 8-ounce (240 milliliters) beverage a week. Sugar-sweetened beverages include sodas, sports and energy drinks, sweetened teas, and fruit-flavored drinks that are not 100 percent fruit juice. [5 Health Problems Linked to Energy Drinks]

The report did not issue any guidelines on the use of non-nutritive sweeteners, such as Splenda (sucralose) or NutraSweet (aspartame), because the panel found few good-quality studies of these sweeteners' benefits or health risks in children, the report said.

Tips for limiting sugar

From a dietary standpoint, the main risks to children's health from taking in too much added sugar are that sugary foods and drinks displace healthier foods in the diet, promote weight gain, and reduce HDL "good" cholesterol and increase triglycerides, Vos said.

To help children and teens meet these new recommendations, a great first step for parents is to stop buying foods and drinks that are high in added sugar, Vos suggested. That way, there is less of it in the home, she said.

Switching to less-processed snacks like fruits, vegetables and nuts can also help reduce kids' sugar consumption, Vos said. In addition, she urged parents to read and compare nutrition labels, which currently list "total sugars," meaning all of the naturally occurring and added sugar in a product.

For most foods — except for fruits and dairy products, which are high in naturally occurring sugars — the total sugar listed on a food label is a good estimate of added sugar, Vos said. Identifying the amount of added sugar in foods will become easier in July 2018, when manufacturers will be required to list this category separately on food labels, she said.

To curb young children's consumption of sugary drinks, it's helpful to simply stop buying these beverages, which makes them less available at home and also saves money on grocery bills, Vos told Live Science. Water and low-fat milk are the two best drinks for children, she said.

For older children, sitting down and talking to them about sugary drinks, and emphasizing the benefits of drinking mostly water, are good strategies, Vos said. Plus, she urged parents to stop buying sugary drinks for themselves.

"Being a role model for your child by drinking water yourself is also very important," Vos said.

Originally published on Live Science.

If a child eats cotton candy, a chocolate bar or any other kind of sugary treat, will a hyperactive frenzy follow? While some parents may swear that the answer is "yes," research shows that it's just not true.

Yes, that's right. "Sugar does not appear to affect behavior in children," said Dr. Mark Wolraich, chief of Developmental and Behavioral Pediatrics at Oklahoma University Health Sciences Center, who researched sugar's effect on children in the 1990s.

Instead, parent's expectations of so-called "sugar highs" appear to color the way they view their children's behavior, Wolraich said. It's easy to see why parents make the link: Sugar is often the main attraction at birthday parties, on Halloween and other occasions when children are likely to bounce off the walls. But all that energy is due to kids being excited, not from the sugar in their systems, he said. 

Related: Why does mint make your mouth feel cool?

If parents believe that sugar affects their children's behavior, "their ideas are reinforced by seeing it in those circumstances," Wolraich told Live Science.

The misconception comes from the idea that increased blood sugar levels translate into hyperactive behavior. It's true that someone with low blood-sugar levels (known as having hypoglycemia) can get an energy boost from drinking a sugar-filled drink. But it's a different story if someone has a sugary treat when he or she doesn't have low blood sugar.

"The body will normally regulate those sugars. If it needs it, it will use the energy," Wolraich said. "If it doesn't need it, it will convert it to fat for storage."

That's right — if you have a donut when your blood sugar level is already just fine, those extra sugars may be converted into fat.

Sugar high?

Much of this information comes from studies that Wolraich and other researchers did in the 1990s.

For instance, the researchers found that mothers rated their sons as more hyperactive when told that the boys had ingested sugar, even when the children hadn't done so, according to a 1994 study in the Journal of Abnormal Child Psychology. In the study, 35 boys ages 5 to 7 were given a drink containing an artificial sweetener called aspartame, which is not made of sugar, but rather of amino acids. Half of the mothers were told that their boys had received sugar.

When the researchers asked the moms about their sons' behavior, the women who were told their sons were given sugar rated their children as more hyperactive, the study found.

Moreover, the researchers also videotaped the interactions between the boys and their moms. The tapes revealed that the mothers who believed their sons had sugar stayed closer to their sons and were more likely to criticize, look at and talk to their sons than the mothers who were not told their sons had been given sugar.

"The placebo effect can be very powerful," Wolraich, who was not involved with the study, said to explain the results.

However, this study (and many others) looked only at sugar consumption at one point in time. So, Wolraich and his colleagues decided to do a longer, nine-week study. However, they still failed to find a link between sugar and hyperactivity, he said. 

Related: Typical toddler behavior, or ADHD? 10 ways to tell

In that 1994 study, published in the New England Journal of Medicine, researchers examined children whose parents thought they were sensitive to sugar. In all, the scientists looked at 25 preschool children, ages 3 to 5, and 23 school-age children, ages 6 to 10. Each family followed a set diet for three weeks at a time: One diet was high in sugar (sucrose), another was high in aspartame, and one was high in saccharin (a noncaloric sweetener).

The study was also double-blind, meaning that neither the families nor the scientists knew which child was on which diet at any given time.

According to cognitive and behavior tests, as well as reports from parents, teachers and researchers, "there were no significant differences among the three diets," indicating that sugar did not effect the children's intellect or behavior, the researchers wrote in the study.

Furthermore, Wolraich and colleagues published a review in 1995 in the journal JAMA that included 16 studies looking at the "sugar high" issue. This review also "found that sugar does not affect the behavior or cognitive performance of children," the researchers wrote in the study.

In fact, the statistician who worked on the 1995 paper, in which the researchers statistically combined the results from all of the studies done until then, said that, "he had never had such consistently negative results." This means that sugar consistently failed to create the fabled "sugar high," Wolraich said.

Originally published on Live Science.

Artificial sweeteners have gone from diet darlings — touted for allowing people to get a hit of sweetness without the calories of sugar — to a more maligned ingredient, as evidence mounts suggesting a complicated net effect on calorie consumption.

Now, a new study done in fruit flies and mice offers insights into how zero-calorie sweeteners may actually increase appetite.

Previous studies in both humans and animals have suggested that artificial sweeteners might promote weight gain, but that research is controversial, said Greg Neely, an associate professor of genomics at the University of Sydney in Australia and the senior author of the new study. Indeed, there is a lot of discussion about how these sweeteners actually affect human health, he said. [Eating Heart Healthy: Which Foods Actually Help?]

In the new study, researchers fed fruit flies either a diet of food sweetened with sugar or a diet of food sweetened with sucralose, the artificial sweetener found in Splenda, for five days. (Neely noted that sucralose was used as the artificial sweetener in part because fruit flies don't seem to like saccharin, the artificial sweetener used in Sweet'N Low.) After five days, all of the fruit flies were put on the sugar-sweetened diet.

The researchers found that the flies that had been fed the sucralose diet started eating about 30 percent more calories than the ones that had been eating sugar from the start, Neely said.

But the researchers wanted to figure out exactly what was going in the flies' brains to drive this response.

Using molecular genetic approaches to study the activity of brain cells, the scientists found that the sucralose activated a "fasting response" in the flies' brains, Neely said. In other words, because the flies were consuming fewer calories when they were fed the sucralose, their brains did not recognize that they were eating enough calories in total. And so, to compensate for this perceived lack of food, the fasting response pathway in the brain triggered the lab animals to eat more, he said.

The activity of cells called "sweet taste neurons" in the flies' brains suggested that this fasting response made sweet foods taste much sweeter to the flies. The fasting response increased the sweetness intensity of natural sugar by 50 percent, Neely said.

In other words, long-term consumption of artificial sweeteners made real sugar seem much sweeter to the fruit flies, Neely told Live Science.

The researchers also found that a neurotransmitter called neuropeptide F played a role in the fasting response in the fruit flies. Mice and humans have an analogous neurotransmitter, called neuropeptide Y.

Additionally, the researchers conducted a similar experiment in mice: when the mice had no genetic changes, those that were fed sucralose-sweetened jellies ate more food than those that were not given the sucralose, the researchers found, according to the findings published Tuesday (July 12) in the journal Cell Metabolism.

However, when the researchers used genetically modified mice that did not have neuropeptide Y, the sucralose had no effect on the animals' appetite, the scientists found. In other words, neuropeptide Y played a role in how artificial sweeteners affected the animals' appetites.

Together, the new findings suggest that in both fruit flies and mice, sucralose promoted increased food intake, Neely told Live Science.

More studies are needed to determine whether the same thing happens in humans, Neely noted. However, the components of the brain's response that the researchers found in the fruit flies and mice, such as the particular neurotransmitter involved, are also found in humans. So, "it's possible [that] sweeteners work through the same pathway" in humans, he said.

Originally published on Live Science.