The 10 Best Fermented Foods For Gut Health, Digestion & Beyond

After taking your very first bite of acidic sauerkraut or sip of tart kombucha, you might not be so sure about fermented ingredients. But they're worth giving another go: Eating fermented foods may come with noteworthy health improvements—and not just for your gut.

Fermented foods are foods (or beverages) that are produced through controlled microbial growth.

This fermentation process can occur naturally1 when microorganisms are naturally present in the raw foods or processing environment. You can also kick off fermentation by adding certain "starter cultures" of microorganisms to food (think using a sourdough starter to make bread).

Historically, fermentation has been used as a means of food preservation across cultures, but its potential health benefits have made it particularly popular in recent years.

Some fermented foods contain probiotics—live microorganisms that support the gut microbiome, explains Sunana Sohi, M.D., a board-certified gastroenterologist. 

Eating probiotics may encourage regular bowel movements, support immune health, and reduce bloating, adds Lauren Manaker, M.S., RDN, L.D., CLEC, a registered dietitian nutritionist. 

Even if they lack probiotics, "fermented foods on their own are beneficial for the gut bacteria," Sohi explains. "The gut microbiome is composed of the over 100 trillion microorganisms2 that live in a symbiotic relationship with us. The health of the gut microbiome is not only important for the health of the GI tract, but it is intricately linked to the health of the entire body."

Consuming fermented foods has been shown to affect gastrointestinal bacteria in the short and long term. Certain fermented foods may even help protect against immune- and metabolic-mediated illnesses, diabetes, cardiovascular disease, irritable bowel syndrome, and cancers, according to a 2023 review3.

Signs you may have an imbalanced gut microbiome (and could benefit from more fermented foods) include bloating or diarrhea, but you should speak with your health care provider for guidance, says Sohi.

That said, "even if you feel well overall, everyone's microbiome can benefit from the addition of fermented foods," she notes. "Fermented foods will keep a healthy microbiome healthy and may go a long way toward moving an unhealthy microbiome in the right direction."

Consider incorporating these research-backed fermented foods into your diet.

A fermented food commonly eaten in Germany, sauerkraut is made by naturally fermenting shredded cabbage and a bit of salt, though starter cultures may also be added. It's been found to contain about a dozen types of microorganisms, including some species of Lactobacillus that show probiotic potential1.

It's also one of the few fermented foods that has been studied for its impact on functional bowel disorders in clinical trials. In a small trial, patients with irritable bowel syndrome consumed 75 grams a day of either pasteurized or unpasteurized sauerkraut containing viable lactic acid bacteria.

After six weeks, both study groups showed a significant reduction in the severity of their IBS symptoms5. (That said, raw cabbage was not studied, so it can't be concluded whether the improvement was due to the fermentation process or the cabbage itself.)

Kimchi is a traditional Korean dish consisting of a blend of salted and fermented vegetables, typically Chinese cabbage and radishes, though other seasonings and foods (e.g., carrot, apple, pear) may be incorporated.

The food generally ferments naturally1, thanks to the microorganisms found on the cabbage, though starter cultures can be used to kick off the process too. 

Since the types and amounts of ingredients in kimchi vary, the exact microbial composition is tough to specify. Still, studies have found that kimchi with large amounts of garlic has a higher concentration of Lactobacillus1, while red pepper powder increases the concentration of Weissella bacteria.

Multiple studies have found links between kimchi consumption and an impact on gut microbiota composition7. A 2018 clinical trial8, for instance, showed that kimchi increased levels of Bacteriodetes and reduced Clostridium sp. and Escherichia coli group counts.

And a 2022 randomized study9 concluded that kimchi can help alleviate IBS symptoms, as it increases fiber consumption and reduces serum inflammatory cytokine levels and harmful fecal enzyme activities. 

A traditional Indonesian food, tempeh is made by fermenting hulled, boiled soybeans with a starter culture at room temperature for about 35 hours.

The exact microbial composition of the umami-rich product varies, but it generally contains lactic acid bacteria, Enterococcus faecium, and Rhizopus filamentous fungi1.

Due to its probiotic content10, tempeh consumption has been linked with improved cognitive function11 in elderly individuals. It's also been shown to enhance beneficial gut bacteria.

Similar to tempeh, natto is a fermented soy product, produced by fermenting cooked soybeans with Bacillus subtilis variant natto1. The supremely sticky and savory food originated in northern Japan13 and may be paired with mustard, seaweed, onion, and steamed rice, among other ingredients.

Through the fermentation process, some of the proteins in the soybeans are decomposed into water-soluble nitrogen compounds14, such as amino acids. Natto contains 18 amino acids15—eight of which are considered essential, meaning your body can't make them on its own. The final product also contains more calcium, iron, potassium, and vitamin B2 than raw soybeans14.

Miso is known as a staple for creating rich, flavorful soups, and it's also a fermented food. The traditional Japanese paste is made by fermenting soybeans with Koji, which is produced from a specific mold. Other bacteria may be used in the fermentation process too1. In the final product, bacteria in the Bacillus and Lactococcus species may be present. 

Incorporating the ingredient into your diet can enhance your gastrointestinal health—and then some. Miso contains highly active enzymes that support the digestion and absorption of essential nutrients and may offer anti‐inflammatory, anticancer, and antihypertensive properties16.

Eating fermented foods isn't the only way you can score their health benefits. Fermented drinks such as kombucha can also be advantageous. This fermented tea originated in China and is created with sugar and SCOBY, a symbiotic culture of bacteria and yeast. 

In a systematic review of 15 studies17, researchers found that consuming kombucha minimizes oxidative stress and inflammation, improves the liver's detoxification process, and reduces intestinal dysbiosis (an imbalance in bacterial composition). They also concluded that kombucha is beneficial for the modulation of gut microbiota.

A creamy fermented dairy drink, kefir originates from the region surrounding the Caucasus Mountains and is produced by adding kefir grains, a starter culture, to milk. It boasts more than 50 species of probiotic bacteria and yeast and has been shown to significantly modulate gut microbiota18.

Good news for folks who are sensitive to lactose: Though made with dairy milk, kefir contains a specific bacteria that reduces lactose concentrations in the drink1, in some cases up to 30%. The fermented beverage may also help relieve constipation, as shown in a small 2017 study. 

Concocted with lactic-acid-producing bacteria19, yogurt is a fermented food that contains Bifidobacterium and Lactobacillus bacteria and has been shown to have positive impacts on the gut microbiome. A recent study found that yogurt consumption temporarily increased levels of multiple bacterial species20 in the gut. 

The creamy snack's benefits expand beyond the gut too. Yogurt consumption has been linked with a reduced incidence of Type 2 diabetes21, potentially due to the probiotic bacteria (which may lower blood cholesterol) or the food's effects on microbiota.

Everyone's favorite pandemic hobby—baking sourdough bread—could give your health a boost. The starter included in the bread is produced by fermenting flour1 (a seven-day process) with lactic acid bacteria and yeasts that live in the flour and surrounding environment.

Sourdough bread may be easier to tolerate than other bread if you have a sensitive stomach; a small randomized control trial22 found that people who ate two sourdough croissants experienced more mild abdominal discomfort, bloating, and nausea four hours later than participants who ate brewer's yeast croissants. 

Break out the charcuterie boards: Cheese is considered a fermented food. Cottage cheese, for instance, can be fermented with citric acid24, while Brie and Camembert are made with lactic acid bacteria25 and other microorganisms. The process concentrates key nutrients and enhances the bioavailability of calcium by removing water. Similar to kefir, fermented cheeses, such as Cheddar, may be more tolerable among individuals with lactose sensitivities24.

It's well-known that a diet rich in unprocessed foods, plant-based fiber, and fermented foods goes a long way toward keeping the microbiome—and, thus, the body—healthy, says Sohi. However, "we are just scratching the surface of our understanding of the microbiome and how what we eat can affect it," she adds.

For example, researchers are still exploring which particular microbes are most beneficial for the gut microbiome, and in what amounts. They're also investigating the best methods for achieving a healthy balance between these different microbes.

As with any new food, it's recommended to slowly incorporate fermented foods into your diet, especially if you have a sensitive gut, says Sohi. "If your microbiome is not used to fermented foods, too much at once might cause some GI distress," she says. 

Eating fermented foods can help populate your gut's microbial community with a skilled workforce of beneficial bacteria. Ideally, you'll eat a few different types of fermented goods (like the foods and drinks on this list) to ensure this workforce is as diverse and effective as possible.

Eating one serving of fermented foods here and there won't meaningfully improve your well-being. You're better off combining a probiotic-rich diet with other gut-healthy habits, like exercising, drinking plenty of water, managing your stress levels, prioritizing sleep, being careful about antibiotic use, and spending time getting a little dirty out in nature.

There's research to show that some probiotic-rich fermented foods can go beyond improving gut health to have measurable impacts on heart health, immune function, and more. Probiotic supplements can also offer unique, targeted bacterial strains for gut health and beyond.

—Emma Loewe, mindbodygreen health & sustainability director