Gut Health: Signs of an Unhealthy Gut & How to Improve It

From probiotic supplements and gut microbiome tests to prebiotic sodas, there's no shortage of products claiming to boost your gut health. That term is being thrown around a lot these days, in fact. But what does gut health really mean? And when is it something you need to worry about?

Dr. Rachel Schiesser, a gastroenterologist at Houston Methodist, is here to explain everything you need to know about keeping a healthy gut, including daily habits, best and worst foods and whether to try a supplement.

What is gut health?

Your gut is more than your stomach — it includes your entire gastrointestinal (GI) tract. The esophagus, stomach and intestines are some of its key components.

"Gut health is a broad term," says Dr. Schiesser. "Today, though, it generally refers to taking good care of your digestive system to optimize your health and reduce the risk of disease. A lot of that comes down to maintaining a healthy gut microbiome, which is the collection of beneficial bacteria that live within your small and large intestine."

Your body is home to trillions of microbes that support digestion, metabolism, immunity and even vitamin and hormone production. These beneficial bacteria play an especially important role in digestion, breaking down food to help us absorb nutrients.

"When our gut microbiome is optimal, it keeps us healthy," explains Dr. Schiesser. "When our microbiome is out of balance — increasing populations of less healthy microbes, decreasing the populations of healthy ones — it can lead to significant downstream effects, contributing to not just digestive problems but broader health concerns, too."

What are the signs of an unhealthy gut?

How do you know if your microbiome is healthy? Ignore that ad you just saw for a gut microbiome test and do a simple gut check instead.

If you regularly experience these digestive symptoms, your gut microbiome may be out of balance:

• Bloating and excessive gas
• Constipation
• Diarrhea
• Heartburn
• Abdominal pain

"These are all signs of an unhealthy gut microbiome and, therefore, an unhealthy gut," says Dr. Schiesser. "Over time, this can predispose a person to a whole host of different issues, so it is important to take action."

Poor gut microbiome health is linked to more than digestive problems like irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). Ongoing research also links it to inflammation outside the gut, potentially contributing to dementia, diabetes, obesity and heart disease.

Should you take a gut health supplement?

The growing popularity in gut health has led to a surge of supplements claiming to support digestion and immunity — probiotics, prebiotics, digestive enzymes, powdered greens, fiber pills, cocktails of all of the above. But are gut health supplements like these worth it? (Related: Do Prebiotic Sodas Benefit Your Health?)

"A few years ago, the American Gastroenterological Association advised against recommending probiotics across the board," says Dr. Schiesser. "They aren't proven to be universally effective for everyone, and they are often very expensive, adding cost without benefit."

Some people with IBS may find probiotics helpful, which is why Dr. Schiesser doesn't discourage trying one out if you're struggling with symptoms. But she advises setting clear expectations.

"What I tell someone considering a probiotic is to pick up a single bottle — just one — and see how it works," recommends Dr. Schiesser. "If at the end of that bottle you don't notice a difference in your symptoms, don't get a second bottle."

As for prebiotics, powdered greens and other gut health supplements, Dr. Schiesser emphasizes a food-first approach. "I really try to encourage people to support their gut health by eating a healthy diet rather than relying on expensive supplements."

How to improve gut health naturally

Your daily habits — especially what you eat and how active you are — play a major role in keeping your gut balanced.

"Everything you eat and drink, how much you move, this all shapes your gut microbiome," says Dr. Schiesser. "For example, fiber-rich foods support good bacteria, whereas taking an antibiotic — while sometimes necessary — can disrupt the balance by indiscriminately killing both harmful and beneficial bacteria." (Related: High-Fiber Foods: How to Get More Fiber In Your Diet)

Your genetics and the microbiome you inherit at birth matter too, but these factors are beyond your control. Instead, focus on what you can change.

Best foods for gut health

A gut-friendly diet incorporates sources of both prebiotics and probiotics:

• Prebiotic foods: Foods rich in soluble fiber (veggies, fruits, whole grains) help feed beneficial bacteria
• Probiotic foods: Fermented foods (yogurt, kefir, sauerkraut, miso) introduce beneficial bacteria into the gut

"I always recommend prioritizing whole, nutrient-dense foods before turning to expensive prebiotic and probiotic supplements," says Dr. Schiesser. "But for people with conditions like IBS, some prebiotic foods are high in FODMAPs and can be tough to digest. In those cases, I typically recommend a specific type of fiber called Sunfiber, which is generally easier to tolerate."

Worst foods for gut health

Ultra-processed foods make up about 60% of the average American's diet — and that's a problem for our gut health.

"We don't fully understand how processed foods affect the gut microbiome," Dr. Schiesser adds. "But we know that consuming large amounts can shift the balance, encouraging more bad microbes than good ones."

And just because a particular food is usually thought to be "healthy" doesn't mean it's not processed. Yogurt, a probiotic that can help support gut health, is a perfect example of how sneaky packaged foods can sometimes be.

Many yogurts on the shelf are full of added sugars. Avoid these options, instead choosing a brand that contains either no added sugar or just limited amounts. Add natural sweetness by topping it with your favorite fruit.

Alcohol is another gut health offender. While red wine has been praised for its potential health benefits, Dr. Schiesser cautions people.

"Alcohol consumption is linked to several cancers, including colon cancer," she warns. "And we're now learning about the harmful effects it likely has on the gut microbiome."

How physical activity supports gut health

Exercise isn't just good for your heart and muscles — it also benefits the gut.

The most straightforward impact is on gut motility — the process of the muscles lining the gut contracting to move food through the digestive system. Slow motility can lead to constipation and bloating. Exercise, however, helps keep things moving. (Related: Am I Exercising Enough?)

"And this doesn't take strenuous exercise, either," explains Dr. Schiesser. "Research has shown that even just light aerobic activity downregulates markers of inflammation in the gut. So, in addition to benefitting gut motility, physical activity might also help shape the gut microbiome itself, encouraging the growth of good bacteria."

Start small for better gut health

Taking good care of your gut doesn't require pricey supplements or extreme diets. Start with simple, consistent habits, like:

• Eating plenty of fiber-rich foods
• Incorporating fermented foods into your diet
• Limiting processed foods and alcohol
• Exercising regularly

"If you're still experiencing digestive issues despite these healthy behaviors, talk to you doctor," says Dr. Schiesser. "They can help whether a supplement might be beneficial for you and rule out whether an underlying condition might be causing symptoms."