While most of us only think of our digestive system as helping to process the foods we eat or being behind the occasional stomach ache, a healthy gut can also impact everything from stronger immunity to improved sleep quality, anxiety management or a boosted mood.

That’s because behind every gurgle and growl there’s a bustling ecosystem of trillions of microorganisms that include bacteria, viruses and fungi that can all affect overall mental and physical well-being.

When any balance is disrupted though, the effects can ripple throughout the entire body. “People often underestimate how much of their overall health is linked to the gut,” says Lisa Young, a registered dietitian nutritionist, author of “Finally Full, Finally Slim” and an adjunct professor of nutrition at New York University. “And even if you don’t have obvious digestive symptoms, your gut could still be out of balance.”

Fortunately, improving your gut health doesn’t require expensive supplements or extreme diets. Simple lifestyle and dietary changes are usually all that is needed to get back on track when things go awry.

What is gut health?

Gut health refers to the optimal functioning of the digestive system, specifically the gastrointestinal (GI) tract and the trillions of microbes that live within it, known as the gut microbiome. “When people talk about gut health, they’re usually referring to the balance of this microbiome,” explains Young.

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For optimal balancing, remember that “a healthy gut has an abundance of ‘good’ bacteria while an unhealthy gut has more ‘bad’ bacteria,” says Dr. Uma Naidoo, director of nutritional and lifestyle psychiatry at Massachusetts General Hospital and the Harvard-trained nutritional psychiatrist behind “Calm Your Mind with Food.”

A few of the “good” bacteria that improve gut health include:

Bifidobacteria , found in fermented vegetables like sauerkraut and pickles and in fruits and whole grains like wheat and sourdough bread.

, found in fermented vegetables like sauerkraut and pickles and in fruits and whole grains like wheat and sourdough bread. Lactobacillus , found in yogurt and other fermented dairy products and foods.

, found in yogurt and other fermented dairy products and foods. Faecalibacterium,-found in fruits like apples and bananas, and nuts and seeds like walnuts and chia seeds, and in legumes like beans and chickpeas.

Such bacteria play key roles not only in digestion but in inflammation regulation, mental health and chronic disease prevention. Harmful bacteria, on the other hand, include Clostridioides difficile, Staphylococcus and Escherichia coli and can collectively or individually cause damage or imbalance to the gut microbiome.

At the same time, everyone’s GI system won’t respond to good or bad bacteria the same way and individual stressors and exposure to environmental toxins like tobacco smoke and air pollution can also play significant roles in overall gut health. “The microbiome is unique to each individual,” says Kelly Jones, a registered performance dietitian and the founder of Student Athlete Nutrition. “It’s influenced by everything from diet to stress to pollutant exposure,” she explains.

How do you know your gut is unhealthy?

Some of the signs of an unhealthy gut are obvious while others are more complex. “An imbalanced gut can contribute to a wide range of common stomach issues including bloating, gas, constipation, diarrhea and food intolerances,” says Young. Other times, she adds, signs of poor gut health include things we don’t think of as being associated with our gastrointestinal system. These can include skin problems, difficulty losing weight and even anxiety or depression.

Other signs to look out for of your gut needing some TLC include getting sick more often than usual, diminished energy levels and difficulty concentrating, says Jones.

When issues persist over extended periods of time, more serious signs may arise. “A chronically unhealthy gut can lead to a ‘leaky gut,’ where the lining of the gut becomes permeable and allows harmful substances to pass into the bloodstream, causing systemic inflammation and chronic disease,” cautions Naidoo.

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How to improve gut health? How to heal your gut?

Improving gut health begins with addressing the lifestyle or dietary choices that cause damage or gut imbalances to occur. Here are some tips:

Increase fiber intake. “Dietary fiber acts as food for beneficial bacteria and supports digestion,” says Young.

“Dietary fiber acts as food for beneficial bacteria and supports digestion,” says Young. Consume more prebiotics and probiotics. “Prebiotics found in foods like oats, lentils and vegetables are fermented in the gut and promote the growth of beneficial bacteria,” says Jones. Probiotic-rich foods like yogurt with live cultures, kefir, kimchi, miso and sauerkraut similarly help restore balance to your gut.

“Prebiotics found in foods like oats, lentils and vegetables are fermented in the gut and promote the growth of beneficial bacteria,” says Jones. Probiotic-rich foods like yogurt with live cultures, kefir, kimchi, miso and sauerkraut similarly help restore balance to your gut. Cut down on ultra-processed foods. Ultra-processed foods and foods and drink that are high in added sugars also harm the microbiome because “they feed bad bacteria and reduce microbial diversity,” warns Naidoo.

Ultra-processed foods and foods and drink that are high in added sugars also harm the microbiome because “they feed bad bacteria and reduce microbial diversity,” warns Naidoo. Manage stress levels and preserve your mental health. Chronic stress can disrupt the microbiome through the gut-brain axis, explains Naidoo.

Chronic stress can disrupt the microbiome through the gut-brain axis, explains Naidoo. Prioritize sleep and exercise. Poor sleep quality is another factor that can harm the microbiome. “Quality sleep supports gut health, while exercise increases microbial diversity,” says Young.

As helpful as each of these recommendations can be individually, it’s the combination of factors that will yield the best results. “A healthy gut is truly the foundation for overall health,” says Young.