5 Foods to Avoid for a Happy, Healthy Gut Microbiome

Tummy troubles? These ingredients could be why.

Let's just say it: Digestive discomfort is the worst. Whether you've been experiencing chronic gut issues for years, or you're new to the woes of a miserable microbiome, one thing is clear—a significant component of our overall health is determined by the (beneficial) bacteria that reside in our gut, aka our microbiome.

"Research has shown that all roads lead to the health of our gut microbiome," says Raphael Kellman, MD, founder of the Kellman Wellness Center in New York City. "Our well-being depends on this inner realm of thousands of microbes residing in our intestines. They greatly impact mood, metabolism, immune function, digestion, hormones, inflammation, and even gene expression." He adds that a balanced bacterial population can mean excellent health, while dysbiosis—or microbial imbalance—triggers disease and chronic illness.

OK, we're listening. But how do you know if you have an unhealthy gut? According to Carielle Nikkel, MS, RDN, a nutritionist with Persona Nutrition, some common symptoms that suggest an imbalance include bloating, gas, and abdominal pain. "Your digestive discomfort could be explained by a variety of issues—from a food sensitivity to an underlying health condition," she says. "But one trend is clear: Digestive issues are often linked to an imbalance of bacteria in your gut. This delicate balance can be altered by your lifestyle, exercise, and antibiotic use (among many other things), but diet is one of the best, most effective ways to improve our microbiome."

By making dietary and lifestyle changes with the bacteria in mind, you can see improvements in every area of the body, including systems that may seem far removed from intestinal health. Here are the five foods Dr. Kellman recommends limiting in the name of your gut microbiome—and overall health and happiness.

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Sugar earned its bad name because of its empty calories that can lead to weight gain. But on a deeper level, sugar should be avoided for the detrimental effects on gut bacteria and inflammation. "Sugar is known to nourish disruptive strains of yeast, allowing them to overgrow and become an unhealthy percentage of the microbiome," Dr. Kellman says.

RELATED: 7 Anti-Inflammatory Foods to Eat Every Day for Long-Term Health

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Diets comprised mainly of animal proteins and fat (like keto and paleo) are marketed as an all-around healthier way to eat. Unfortunately, they do little to sustain the health of the microbiome–which requires a substantial amount of plant fibers known as prebiotics to make necessary nutrients for our health. These prebiotics create short-chain fatty acids, vitamins, and natural antibiotics that keep us safe from pathogens. A microbiome-friendly diet is high in plants and uses healthy animal proteins as a side dish.

RELATED: Your Gut Needs Prebiotics and Probiotics—But What's the Difference?

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Plant Pesticides

The microbiome is highly sensitive to chemicals, toxins, and pesticides—especially those coming from the food and water we drink. "If you have a sensitive gut, avoid foods that may have been exposed to plant pesticides (especially those on the Dirty Dozen list)," Dr. Kellman advises. "Choose organic fruits and veggies, stick to consuming animals raised without hormones, and drink filtered water."

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While dairy can be beneficial for some, for those with an allergy or intolerance, eating it leads to inflammation, leaky gut, and reactions that can affect the immune system. "Many people benefit by removing it for a period of time and reintroducing it later," says Dr. Kellman. Same goes for gluten: It isn't bad for you, but if you have an allergy or sensitivity, giving it up is a no-brainer for good gut health.

RELATED: 5 Healthy Foods That Are High in Vitamin D (and Why It's So Important to Eat Them)

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HFCS, Additives, Preservatives, Food Colorings, and Refined Vegetable Oils

This last group is a mixed bag of detrimental products, all of which have a few big things in common: They all promote inflammation, are highly processed, and can lead to imbalances in bacterial communities. (To clarify, refined vegetable oils refer to varieties like soy, corn, sunflower, and cottonseed, not healthy oils like olive and avocado.)

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  1. Menees S, Chey W. The gut microbiome and irritable bowel syndromeF1000Res. 2018;7:F1000 Faculty Rev-1029. doi:10.12688/f1000research.14592.1

  2. Davani-Davari D, Negahdaripour M, Karimzadeh I, et al. Prebiotics: definition, types, sources, mechanisms, and clinical applications. Foods. 2019;8(3):92. doi:10.3390/foods8030092

  3. Rinninella E, Cintoni M, Raoul P, Gasbarrini A, Mele MC. Food additives, gut microbiota, and irritable bowel syndrome: a hidden trackInt J Environ Res Public Health. 2020;17(23):8816. doi:10.3390/ijerph17238816

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