Some gut health supplements lack research and may do more harm than good.

Experts recommend food first: fiber, fermented foods and variety support your microbiome.

Always talk to a health care professional before trying OTC enzymes or antacids.

Gut health isn’t just about good digestion. A healthy gut microbiome—the colony of bacteria and other microorganisms living in your intestines—is also important for immune health, heart health, brain health and more. The foods you eat can significantly impact the makeup of your gut microbiota, for better or worse. But what role do supplements play in gut health?

Many supplements promise to heal your gut, but research does not support many of these claims. We spoke to nutrition experts to find out what you should and shouldn’t do for gut health. Registered dietitians encourage a food-first approach instead of relying on expensive, unregulated supplements. Read on to see which ones they say to skip.

1. Probiotics

Probiotic supplements often claim to improve health by restoring healthy gut bacteria and some research suggests they may help reduce the symptoms of irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). “For probiotics to be effective, you need to take the right strain at the right dose for your condition. Probiotics may worsen symptoms in many people with small intestinal bacterial overgrowth (SIBO),” says Kerry Conlon, M.S., RD.

According to Kelsey Costa, M.S., RDN, most people can “cultivate a healthy gut microbiome by engaging in regular exercise and consuming a diet rich in whole, minimally processed foods.” Since they are supplements, the Food and Drug Administration does not regulate probiotics. Over-the-counter probiotics available in pharmacies and stores may not be high quality, and it’s even possible that some products may not contain the probiotic bacteria listed on the label.

2. Greens Powders

Many greens powders claim to improve gut and overall health; however, there isn’t much research to back up these claims. One thing most greens powders don’t provide is dietary fiber. Conlon says, “Relying on powders for nutrients instead of whole fruits and vegetables deprives your body of fiber, an essential nutrient for gut health.” Fiber feeds beneficial gut bacteria and promotes digestion and nutrient absorption.

3. Digestive Enzymes

Over-the-counter digestive enzymes are often thought to relieve acid reflux, gas and bloating. The market for these products is substantial, but it’s not known if they are safe or effective since they are unregulated by the FDA and limited research is available.

The body naturally produces digestive enzymes to help break down food. “Most people don’t need to supplement with digestive enzymes unless they have certain medical conditions, like cystic fibrosis or liver problems,” explains Amanda Sauceda, M.S., RD.

According to Costa, “The precise ingredients, dosage and potency of digestive enzyme products could vary significantly without any guaranteed outcomes or firm understanding of potential side effects.” Costa recommends talking to your health care provider before taking OTC digestive enzymes. Even then, take only the specific enzyme supplements directed by your health care provider and watch for potential side effects.

4. Over-the-Counter Antacids

Antacids—an OTC remedy for treating heartburn, acid reflux and indigestion—work by neutralizing stomach acid, providing quick relief from discomfort. “While antacids are technically medications and not supplements, they are widely available OTC and are overused by many,” says Costa.

Research suggests that proton-pump inhibitors (PPIs)—a commonly used type of antacid—may significantly change the makeup of the gut microbiome. This may result in an overgrowth of harmful gut bacteria, changes in nutrient absorption and inappropriate immune responses.

PPIs should only be used as needed, as directed by a health care provider.

Gut-Healthy Eating Tips

According to a recent review from Gut Microbes, polyphenols and probiotics found in fruits, vegetables, whole grains, legumes, nuts and seeds support gut health and the growth of good gut bacteria.

For a healthy gut, focus on consuming a variety of plant-based foods while limiting foods high in added sugar and saturated fat. On your next shopping trip, Sauceda suggests picking up a fruit, veggie or grain you haven’t had in a while.

Aim to consume at least 25 grams of fiber daily and eat lots of fermented foods, like kefir, sauerkraut and kombucha. Fermented foods naturally contain probiotics that support gut health, while fiber feeds beneficial gut bacteria. Add a fruit, vegetable or whole grain to each meal and snack to help you hit your fiber goal.

Our Expert Take

Gut health is best achieved through a healthy lifestyle including eating a balanced and variety-filled diet, regularly exercising, getting enough quality sleep and managing stress in a healthy way. Instead of spending money on expensive supplements that might not be effective, eat a balanced diet that is high in fiber and low in added sugars and saturated fats. Focus on including a variety of plant-based and fermented foods.