The food you put into your body doesn’t just satisfy your taste buds — it also feeds the trillions of organisms living in your gut. If you eat the right things, you will reap the reward of physical and mental health, and feeding your gut the wrong things may actually harm the little critters that live in your gastrointestinal tract.
The idea of tiny organisms living in your belly may seem a bit unsettling, but these are helpful — a.k.a. good — bacteria. In case you don’t know, gut bacteria help your body digest food and therefore absorb the nutrients you need. Not only that, but digestive health plays an important role in immune function and even mental health.
We spoke with two registered dietitians — Tamara Freuman, a dietitian at New York Gastroenterology Associates and author of the forthcoming book, Regular, and Alyssa Lavy, owner of Alyssa Lavy Nutrition & Wellness, a private practice focused on digestive health — about the importance of gut health and the best foods to nourish the microbiome.
What is gut health?
The term “gut health” is trending on social media, but you may be surprised to learn there is no true definition of the phrase. When experts discuss gut health, they are usually referring to the microbiome or the trillions of microorganisms that reside in the gut and play an impact on overall health.
“The composition and health of the gut microbiota have been linked to a variety of health conditions, both GI and otherwise,” says Duker Freuman. “[Poor gut health] is associated with an increased risk of inflammatory bowel diseases and digestive system cancers (especially colon cancer) and conditions like frailty, mood disorders and metabolic diseases, like Type 2 diabetes and nonalcoholic fatty liver disease,” adds Duker Freuman. Conversely, a healthy gut may reduce the likelihood of developing chronic diseases, like obesity, diabetes, irritable bowel syndrome, inflammatory bowel disease, depression, and cardiovascular disease.
How do you make sure you have a healthy gut?
There are multiple ways to control the composition of the gut microbiome, including what you do and don’t eat. “The American Gut Project, which is the largest study to have looked at the human microbiome, found that increased plant diversity within the diet was associated with increased microbial diversity,” says Lavy. Research suggests that the most diverse microbiomes are more resilient and stable. On the contrary, diets that are high in ultra-processed foods, sugar and saturated fat have been linked to less gut diversity and favor bacteria that are significantly associated with a higher risk of cardiac events, strokes, and Type 2 diabetes.
It’ll probably come as no surprise that the best foods for gut health are plant-based and low in saturated fat and sugar. But Duker Freuman emphasizes that “habitual intake of these foods is what promotes good gut health; eating beans once in a blue moon doesn’t have some magically transformative impact on gut health.”
According to both dietitians, you should fill your plate regularly with these eight kinds of food to build a healthy gut.
High fiber foods
Fiber is a type of carbohydrate that is known for its role in keeping the digestive system moving. There are two types of fiber– soluble and insoluble. Soluble fiber absorbs water and turns into a gel during digestion. Insoluble fiber adds bulk to stool and helps food pass through the GI tract. Both types of fiber are necessary components of the diet and contribute to good gut health.
Fiber is found in a variety of plant-based foods, and it’s especially robust in:
- Vegetables, especially broccoli, cauliflower, brussels sprouts potatoes with skin and kale
- Pulses (beans, lentils and peas)
- Fruits, especially pears with skin, apples with skin and berries
- Nuts and seeds
- Whole grains, such as brown rice, farro, barely, quinoa and wheatberries
Two plant-based foods with notable fiber include:
Oats are known for their soluble fiber, which can improve stool consistency and bowel regularity. “They also contain beta-glucan, a type of soluble fiber that is thought to reduce cholesterol,” says Lavy. A review of the research claims that eating oats increases the bacterial count in the gut, reduces gut permeability and leads to more inflammation-fighting short chain fatty acids.
This deliciously sweet green fruit has vitamin C, potassium and 2 grams of fiber per kiwi. In addition to the fiber, the kiwi has another compound that may help keep you regular. “Recent research shows [kiwi] may be helpful in improving motility and stool consistency, which is likely due to actinidin, an enzyme present in the fruit,” says Lavy.
Probiotics are living microorganisms that reside in the gut and may have health benefits. The most common probiotics are Lactobacillus and Bifidobacterium. They develop during the fermentation process that occurs when making foods like tempeh, sauerkraut, kimchi, kefir and kombucha. Microbes are also added yogurt to break down the sugar lactose into lactic acid.
The following foods are rich in probiotics:
Have you ever noticed that one of the ingredients in yogurt is “live active cultures”? These are the live bacteria that ferment the milk product to create yogurt or its familiar tangy cousin, kefir. “Fermented foods have their own diverse and unique microbial populations, which can have transient health benefits as they pass through our guts on their way out the proverbial back door,” says Duker Freuman. Plus, research has found that fermentation can result in the release of bioactive peptides (organic substances), which may reduce cholesterol.
Sauerkraut and kimchi
Both of these tangy condiments are made from cabbage fermented in a salty mixture. The end result is a good-for-the-gut crunchy topper for sandwiches, stir-fries and more. Both sauerkraut and kimchi contain a probiotic that increases immune response and reduces inflammation. Not to mention that a study in mice suggests that probiotics in kimchi may help treat inflammatory bowel disease, but more research is needed.
If you’ve never had tempeh before, say hello to one of your new favorite plant-based proteins. Tempeh is a fermented soy product that is blended with a grain– usually rice– and formed into a solid block. It’s easy to slice, marinate and cook, and it’s also full of probiotics. The research on tempeh is limited, but one study suggests that eating this soy product increased the beneficial bacteria in the gut. Another interesting study gave elderly participants tempeh-derived probiotics in supplement form for 12 weeks. The researchers found that one of the probiotics in tempeh increased memory, language and spatial perception in the participants.
Prebiotics are fibers that feed the microbes in the gut. Eating these fibers helps the probiotics in the gut flourish and grow. Luckily, they're found in several plant foods, including beans, artichokes, garlic, onions, asparagus, barley and wheat bran.
Here are three prebiotic-rich stand-outs:
“Beans support a healthy gut microbiota specifically through their prebiotic fiber, which nourishes some of the microbes that produce short-chain fatty acids,” says Duker Freuman. “These short-chain fatty acids reduce the pH of the colon, which plays a role in colon cancer prevention, and they inhibit disease-causing species of bacteria,” adds Duker Freuman. Plus, recent research suggests that some varieties of beans may also improve the integrity of the intestinal barrier, which keeps bacteria from getting too close to the inner layers of the gut wall and provoking immune cells. Not to mention that beans are affordable and versatile.
Artichokes are also rich in prebiotic fiber, which “selectively feed health-promoting members of our microbiota, including species in the Lactobacilli and Bifidobacteria genera,” says Duker Freuman. She adds that these microbes provoke the intestinal cells to secrete mucus, which improves the mucosal barrier function. They also produce short chain fatty acids, which promote an anti-inflammatory environment throughout the gut.
It’s time to stop avoiding this starchy fruit, which is advantageous for gut health. Not only are bananas full of potassium, a nutrient that lowers blood pressure, but they are also known for treating constipation. Bananas contain prebiotic fiber and resistant starch, a type of carbohydrate that is absorbed slowly in the large intestines and results in fermentation.
The bottom line
“It makes more sense to think about overall dietary patterns for good gut health rather than specific foods,” says Duker Freuman. In other words, these foods are great for gut health but you don’t need to try to limit yourself to them. Just integrate them into your meal plan.
Duker Freuman also notes that a diverse diet full of plant-based foods is the best for overall gut health, so choose the high fiber foods you enjoy the most. “Your consistent, regular eating habits are what promote long term gut health,” says Duker Freuman, “there are no shortcuts here.”