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Gut health: What is it and why is it important?

woman cooking with her daughter to support gut health
(Image credit: Getty Images)

You may have heard the term ‘gut health’ and wonder what it means – surely a healthy gut is just one that digests your food effectively? While this is true, gut health has an impact on the health of your entire body, with increasing evidence suggesting a healthy gut microbiome is important for our mental health, as well as an effective immune system.

Our gut breaks down the meals we eat into a functional form that can enter the bloodstream and go where it is needed in the body. Unfortunately, things can go wrong at several stages in this process, from serious digestive diseases to food intolerances causing problems with how our body extracts nutrients from food.

But what happens when our guts become unhealthy, and how can we maintain a healthy balance? Read on to discover the essentials of good gut health, as well as how the best probiotics can make a difference.

What is gut health?

From the oesophagus to the bowel, gut health covers the health of the entire digestive system – the parts of our body responsible for breaking down our food into individual nutrients we use to run our bodies. Each part of the gut has a different job and different colonies of microorganisms do the job of breaking down food into more digestible formats. 

Research (opens in new tab) shows that diet has a direct impact on the population of these colonies, with diets high in fat or sugar encouraging bacteria that consume these nutrients, and diets high in fibre encouraging fibre-loving bacteria that generally live further along in the gut. So remember, when you eat you aren’t just feeding yourself, you are feeding billions of gut bacteria too, and your dietary choices impact which bacteria do well and which die off. 

There is evidence that these bacteria may have an impact on longevity, as indicated in the unique gut bacteria of people who live to be 100. Additionally, some gut bacteria might even give athletes an edge, thriving in their bodies and improving their performance.

illustration of colorful microbes in the intestinal tract


A healthy gut communicates with the brain through the neural network and using hormones - this is how we know when we’re hungry and what we might fancy to eat. Everyone’s gut microbiome is unique, so foods that help one person to thrive may cause irritation in others. The most common food intolerances are to gluten, found in wheat, and lactose and casein, found in milk. Some people can digest these components with no issues and other people will find themselves experiencing intense discomfort and unpleasant symptoms if they consume these foods.   

Why is gut health important?

The gut is hugely important for immune function, with the gut wall providing a barrier that, when functioning properly, prevents viruses, fungi and ‘bad’ bacteria from entering the bloodstream. Unfortunately, this barrier sometimes becomes permeable, known colloquially as a ‘leaky gut’, which means these nasties can break through and make us sick. Conditions such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD) and coeliac disease can make people more prone to developing permeability in the gut wall, making them more vulnerable to disease or infection entering the body this way.

Research (opens in new tab) shows that gut health also has a knock-on impact on mental health. Known as the ‘second brain’, there’s a reason we feel a lot of our emotions in our guts. Gut bacteria have the power to stimulate our nervous system, sending messages to our brains through the vagus nerve. They can also release hormones identical to those our own systems release, making them little pilots with a large impact on our bodies and decision making given how tiny they are. This communication between gut and brain is known as the gut-brain axis. Stress can also impact these bacteria, as a lot of them are hormone-sensitive, which may lead to an imbalance. 

What are the signs of good gut health?

So how do you know if you have a healthy gut? Cristy Dean, dietician and gut health specialist for Fettle and Bloom, (opens in new tab) tells LiveScience a healthy gut can be measured in a number of ways. 

“This can be from how often we go to the loo to pass a stool, to the time it takes for food to transit through the body,” she says. “Everybody is different, however it is considered normal to go between three times a day and three times per week. Very slow or very fast transit time can indicate something isn't right with digestion. Stools should be medium to dark brown, smooth, sausage-like and be passed without pain or excessive bloating or gas.” 

What are the signs of bad gut health?

It is estimated (opens in new tab)that 60-70 million Americans suffer from digestive problems, making up 12% of inpatient procedures, so poor gut health is a very common problem. Upsets to gut health can occur for a number of reasons, but the main signs that you might have a problem are:

  • Bloating
  • Loose stools
  • Constipation
  • Heartburn
  • Nausea and vomiting 

woman holding her stomach in pain

(Image credit: Getty Images)

Other, slightly more obscure symptoms may not seem like they have much to do with gut health, but can actually be strong indicators that something is wrong. 

  • Fatigue and poor sleep- a 2020 study (opens in new tab) found that an imbalance in our gut health can lead to disturbed sleep patterns and low energy.
  • Skin irritation - it seems strange that your external immune barrier (skin) and internal immune barrier (gut) would be linked, but research (opens in new tab)indicates that skin irritation can be a symptom of poor gut health.
  • Bad breath/halitosis - it makes sense that symptoms of bad gut health would affect the mouth, as this is the gateway to the gastrointestinal tract, but you may not realise that bad breath can actually be a symptom (opens in new tab)that all is not well  in the rest of the digestive system.

Dean recommends looking out for changes and symptoms that are abnormal for you, as gut health is very personal. “Changes in bowel habit can be a sign that something is wrong, such as increased bloating, gas, diarrhoea, heartburn or waking in the night to pass a stool,” she says. “Sleep disturbances, increased fatigue, skin irritation, food intolerances and unintentional weight changes can all be linked to an unhealthy gut.”

If you think you are experiencing any of the symptoms, it might be worth visiting your doctor or a gut health specialist to discuss potential causes and treatments. 

How to support your gut health

There are several ways you can give your gut a helping hand and promote good gut health. Consumption of probiotics, live digestive bacteria and yeasts that we can take as a supplement, support a healthy gut flora as they are designed to reach the gut alive and boost the populations of ‘good’ bacteria and yeasts. Keeping these bacteria healthy prevents the overgrowth of ‘bad’ microorganisms, which can cause digestive issues. 

Prebiotics can also support the health of your gut microbiome, as they are a source of food for your gut flora, helping to keep populations balanced. 

Dietary fiber plays a role in slowing down gut motility, giving the large intestine time to absorb water so it is not passed in stool. It is also a bulking agent, binding indigestible matter together to be passed by the body as stool.

Dean recommends eating a variety of foods to support good gut health. “We can support our gut health by increasing the microbial diversity. This is the measure of the different types and amount of bacterial species in the gut microbiome,” she says. 

“Ideally, we want high — increased numbers of species — and a high evenness — no dominating species. A good place to start is by getting a varied diet, rich in plant foods. Fruits, vegetables, wholegrains, nuts and seeds are prebiotic foods that feed our beneficial bacteria and help our microbiome to thrive.”

Lou Mudge
Health Writer

Lou Mudge is a health writer based in Bath, United Kingdom for Future PLC. She holds an undergraduate degree in creative writing from Bath Spa University, and her work has appeared in Live Science, Tom's Guide, Fit & Well, Coach, T3, and Tech Radar, among others. She regularly writes about health and fitness-related topics such as air quality, gut health, diet and nutrition and the impacts these things have on our lives. 

She has worked for the University of Bath on a chemistry research project and produced a short book in collaboration with the department of education at Bath Spa University.