Why Is Too Much Salt Bad for You?

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Each week, MyHealthNewsDaily asks the experts to answer questions about your health. This week, we asked nutrition experts: Why is too much salt bad for you? Their answers have been edited and condensed for space.

Dr. Zachary Bloomgarden, professor at the Mount Sinai School of Medicine in New York City:

The simple answer is that salt is associated with higher blood pressure. About 50 to 70 million people in the U.S. have hypertension, and all of them would benefit from a low-salt diet.

Studies of the DASH diet (Dietary Approaches to Stop Hypertension) show just how much of a difference salt intake can make. It's a very healthy, low-sodium diet, which has a lot of vegetables and not a lot of salt. The DASH diet can drop high blood pressure significantly.

The problem is that salt is very tasty, just like sugar. The combination of salt, sugar and fat is unbelievably tasty. All mammals have the desire to eat these bad foods.

The amount of salt that is available today, just like the amount of sugar that is available today, is far beyond what we were meant to have in our diets. 

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Rachel Johnson, professor of nutrition at the University of Vermont in Burlington:

Excess sodium increases blood pressure because it holds excess fluid in the body, and that creates an added burden on the heart. Too much sodium will increase your risk of stroke, heart failure, osteoporosis, stomach cancer and kidney disease. And, 1 in 3 Americans will develop high blood pressure in their lifetime.

Limiting your sodium is tough because about 75 percent of sodium in Americans' diets comes from processed or prepared foods, not salt that we add at the table. If you're a savvy nutrition label reader, it can be shocking.

Even foods such as breads and cereals can have high amounts of salt. We call it a silent killer because a lot of people don't realize they have high blood pressure. 

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Marisa Moore, registered dietician and spokesperson for the Academy of Nutrition and Dietetics:

The average American eats about 3,400 milligrams sodium a day, but the recommended amount for a healthy person is 2,300 milligrams a day. For people with high blood pressure or diabetes, African Americans, and anyone who is age 51 or older, the daily recommendation is 1,500 milligrams of sodium.

So, most people are consuming double what they need in terms of salt.

For most people, a high sodium diet can lead to retaining fluid. And for some sensitive people, retaining fluid can lead to higher blood pressure, which puts someone at higher risk of stroke, heart disease and kidney disease. Whenever you have a high blood pressure, it causes your heart to have to work a lot harder and it can cause damage to blood vessels and the heart muscle itself.

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Stephanie Dunbar, registered dietician, director of Nutrition and Medical Affairs at the American Diabetes Association

Excess salt is has been linked to hypertension, and of course hypertension is a risk for heart disease.  Some populations of people are very sodium sensitive, meaning when they eat sodium they retain fluid and their blood pressure rises.

There's some research that shows if everybody reduced sodium in their diet, the rates of heart disease in the United States would go way down.

With our current food production it's very difficult to cut out sodium. A slice of bread can have 250 milligrams of sodium alone. Unless you get back to a diet where you're really cooking from scratch, and not using processed foods or canned foods, it's really hard to reach that recommendation.

Salt has been used for hundreds of years as a preservative, and some food makers use it as a flavoring because it's cheaper. It's more expensive to use other herbs and spices to make food taste good better than to add salt.

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Mary Ellen DiPaola, outpatient dietitian at the University of California San Francisco Medical Center

Sodium chloride, which we acquire from table salt as well as from salted food products, is required for metabolic functions in the body and helps regulate fluid volume. The issue with sodium is similar to sugar: The average American consumes well above the recommended amount.

If we are consuming fresh, whole and natural foods, sodium intake can be reduced quite easily. Avoiding added salt, soy sauce or other salty condiments will also help reduce total sodium intake. Look for products less than 140 milligrams per serving, which is considered to be low in sodium.

Requesting less sodium added to foods in restaurants is another means to reduce total daily sodium. More importantly, consider cooking at home with fresh foods and low sodium recipes.

And why should you lower sodium intake? Sodium in excess can increase blood pressure in those who have hypertension (high blood pressure), it can make the body retain fluids which may cause swelling in susceptible individuals, and salty foods tend to also be high in total fat and calories – leading to excess total calorie intake, overweight and obesity.

A long term problem related to hypertension is kidney disease, a chronic illness which can lead to kidney failure.

Lauren Cox
Live Science Contributor
Lauren Cox is a contributing writer for Live Science. She writes health and technology features, covers emerging science and specializes in news of the weird. Her work has previously appeared online at ABC News, Technology Review and Popular Mechanics. Lauren loves molecules, literature, black coffee, big dogs and climbing up mountains in her spare time. She earned a bachelor of arts degree from Smith College and a master of science degree in science journalism from Boston University.