5 Foods That Could Be Messing With Your Gut

History and common sense say we should always trust our gut—but in order to do so, we need it to be functioning at its best.

The consensus among nutrition and medical experts is that our gut health can affect our overall well-being for better or worse. “The health of the gastrointestinal tract is extremely important because the gut contains a majority of the immune system, with just a single layer of cells lining it,” says Maureen Leonard, M.D., clinical director for the Center for Celiac Research and Treatment. “This single layer of cells separates the immune system from the many environmental exposures we ingest.”

Since our intestines filter good things (like nutrients) from bad things (like toxins), our gut is one of our body’s first lines of defense against the outside world, according to Stephanie Dunne, M.S., R.D., C.D.N., I.F.N.C.P.

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Researchers still have much to learn about our gut, but here’s what we do know: The bacteria that live in our gut (which are often called the ‘microbiome’) contribute to our overall health and may play a role in the development of disease, our mood, and our weight, Dunne says. Everyone’s gut is different, depending on a person’s individual biology, environment, medical history, medication use, and diet, explains Leonard. This means we all deal with toxins in different ways, and we each have different levels of intestinal permeability (a measure of how easily materials can pass through the cells lining our gut and into our body), says Leonard.

Related: The Term ‘Leaky Gut’ Is All Over The Internet—But What Exactly Is It?

And though our diet alone doesn’t determine the fate of our gut health, nutrition is an important part of keeping our microbiome strong, diverse (the more strains of good bacteria the better!), and able to ward off inflammation. “Lifestyle choices, stress management, and nutrition are all pieces of the puzzle, and none of them can be ignored if we really want a happy digestive tract,” Dunne says.

Is your grub holding back your gut health? Read on to learn what foods to cut back on (and what to eat instead) to keep your insides as happy as possible.

As much as those refined carbohydrates and sweets tempt our taste buds, they are less-than-ideal food for the good microorganisms that live in our gut. Our relationship with these good gut bugs works like this: We feed them, and, in turn, they provide us with vitamin K2 and short-chain fatty acids, according to Dunne. The good gut bugs feed on complex carbohydrates and their fiber, while the not-so-friendly bacteria in our gut feed on refined carbs and sugar. The stronger our little colony of healthy bacteria—and the weaker the colony of bad guys—the better our gut is able to keep us regular and healthy.

“By reducing the intake of refined carbs and increasing our intake of fiber, we are feeding the good guys and starving the bad guys,” Dunne says. “We, in turn, reap the benefit of having more good guys living in our gut.” So by swapping sugar and refined carbs like white breads or pastas for complex, whole-food sources like fiber-rich beans, whole grains, nuts, fruits, and vegetables, we give our healthy bacteria the food it needs, says Maggie Moon, M.S., R.D.N., author of The MIND Diet.

Knocking back cocktails is a surefire way to diminish our gut health, according to Ana Johnson, M.S., R.D., C.D.E. “Alcohol is inflammatory, and causes all of your body systems to become inflamed, including your digestive system,” she says. Ever experienced symptoms like gas, bloating, diarrhea, or even acid reflux or heartburn after drinking? Yep, there’s your evidence. Alcohol can also make conditions like irritable bowel syndrome worse—and it can even lead to gastritis (inflammation of the lining of the stomach.)

The only way to truly prevent this damage is to ditch your cocktail for a mocktail. Alcohol is a toxin, and the most effective way to reverse its effects on your body is to stop putting it into your system, says Johnson. Eating an anti-inflammatory diet (more on that later), managing stress, and getting enough sleep will help counteract the effects of alcohol, but can’t completely cancel them out, she says.

Sadly, all alcohol—from tequila to craft beer—is equally damaging. Johnson recommends avoiding alcohol as much as possible, and limiting yourself to one (for women) or two (for men) drinks when you do imbibe.

Don’t freak out. We’re not about to say everyone and their mother needs to go gluten-free.

When we eat gluten (the type of proteins found in grains like wheat), our body releases a protein called zonulin, which creates spaces between the intestinal cells. When these spaces are too large, substances that otherwise wouldn’t be able to fit through these spaces are able to pass into our body.

“Even though everyone releases zonulin, some people release more of it and are slower to close up these spaces that are formed,” she says. That’s why some people can eat gluten without issue, while others find it leads to symptoms like diarrhea, cramping, or swelling.

Blood tests can help determine if you have celiac disease (an autoimmune disorder in which gluten damages the small intestine), but won’t necessarily flag less severe sensitivities, which can manifest as symptoms like headaches, joint pain, or brain fogginess, Dunne says. If you suspect you have a gluten issue, work with a dietitian to cut out gluten-containing foods for about three weeks. At the end of the three-week period, you’ll eat something with gluten in it and gauge your body’s reaction.

If gluten is an issue for you, you may need to cut back on gluten-containing foods (like anything made with wheat) or nix them completely, says Dunne. From there, focus on incorporating foods and nutrients that support your gut health, like omega-3 fatty acids (found in flax seeds, walnuts, fatty fish, chia seeds, soybeans, and shrimp), vitamin A and vitamin C (found in carrots and sweet potatoes, and kale and broccoli, respectively), and zinc (found in spinach and kidney beans).

Related: All The Things You Didn’t Know Omega-3s Could Do For Your Health

Research suggests omega-3s may support the gut’s barrier function, while vitamin A helps regulate the gut’s immune cells, Dunne says. Meanwhile, vitamin C is a powerful antioxidant and zinc is necessary for cell division, which is crucial for the turnover of cells in your gut.

Eating meat doesn’t automatically lead to an unhappy gut, but focusing less on animal-based foods and more on plant-based foods seems to be more gut-friendly, says Moon. “That doesn’t mean no steak ever; it just means more plants more often,” she says. Not convinced? Research—like this study, published in Cell Metabolism—has associated eating plant proteins with a lower mortality risk than eating animal proteins.

What makes plant foods so gut-friendly? Many vegetables, fruits, and grains contain indigestible fiber called prebiotics, according to NYC-based nutritionist Cara Anselmo, M.S., R.D.N., C.D.N. These prebiotics act as food for the good bacteria, called probiotics, that live in our gut. And though many of us think of dairy foods like yogurt and kefir as the ultimate food sources of those probiotics, they’re also found in fermented plant foods like kimchi and tempeh.

Related: Support your good bacteria with a probiotic supplement.

To up your diet’s plant power, base your plate in whole, fresh fruits and veggies and then add whole grains like barley, wheat berries, or quinoa. To make sure plant-based meals pack enough protein, incorporate sources like beans, tofu, nuts, and seeds frequently, says Anselmo. (Those whole grains provide some protein, too, BTW.)

If you’re a carnivore at heart, pick fish or poultry over red meat, and avoid processed meat, she says. (While researchers are still figuring out the relationship between specific foods and our gut, excess consumption of processed meats has been linked to colorectal cancer, according to the World Health Organization.)

Many of the processed foods we eat contain additives and other hard-to-identify ingredients that may negatively impact our gut health. The average American diet, which is high in sugar, fat, refined foods, and emulsifiers, is linked with lower microbial diversity and inflammation, says Boston-based dietitian Kate Scarlata, R.D.N. And these two health factors are commonly associated with health problems like cardiovascular disease, obesity, diabetes, autoimmune disorders, irritable bowel syndrome, and inflammatory bowel disease, she says.

Consider emulsifiers, for example. (You’re probably wondering what they are, but you’ve probably eaten something that contains them today.) These common additives—lecithin and carrageenan are two you’ve likely seen—are used to stabilize processed foods, like dairy-free milks and chocolate bars. Though more human study is needed, an animal study published in Nature found that ingesting emulsifiers decreased the diversity of mice’s microbiomes, triggered inflammation in the gut, and contributed to the breakdown of the protective mucus that lines the gut wall.

The best way to guarantee your eats won’t hurt your gut health is to keep processed foods off the menu as much as possible. “Balance your plate with whole grains, lean protein, healthy fats such as olive oil, nuts, seeds, and a wide array of colorful produce,” says Scarlata.

Pin this handy infographic and keep your grub gut-friendly: