Kimchi, Greek yogurt, sauerkraut, kombucha—these are fermented foods, meaning they’ve gone through a preservation method called fermentation.
This process uses live microorganisms like bacteria and yeast to break down key ingredients and create new compounds.
Eating fermented foods regularly can offer some impressive health benefits—though there may be a potential downside, too. Here’s what it may do to your body.
Many fermented foods contain probiotics—live microorganisms that can “improve the diversity and balance of your gut microbiome,” Elena Ivanina, DO, MPH, a triple board-certified integrative gastroenterologist and founder of Gut Love, told Health.
The gut microbiome refers to the trillions of microorganisms, including both good and bad bacteria, that live in your intestines.
Factors like antibiotic use or conditions such as inflammatory bowel disease can disrupt this balance. Replenishing beneficial bacteria, however, has been associated with improved digestion, stronger immune function, and better overall health.
That said, the benefits may be temporary—probiotics’ presence in the gut microbiome is often short-lived, said Adam Pont, MD, board-certified gastroenterologist at Medical Offices in Manhattan.
It’s also worth noting that not all fermented foods contain probiotics. Items like sourdough bread, beer, and wine are fermented but typically lack live probiotic strains. Foods with probiotics will often say “contains live active cultures” or “naturally fermented.”
Certain probiotic strains may help your body absorb nutrients more effectively, including:
That’s because the fermentation process “can stimulate the production of enzymes that assist in breaking down certain nutrients,” gastroenterologist Sarah J. Robbins, MD, told Health.
So, not only can your daily bowl of Greek yogurt give you a nutrient boost, but it may also help your body get more out of the rest of your diet.
By supporting beneficial gut bacteria that ferment dietary fiber, the probiotics in fermented foods enhance the production of molecules called short-chain fatty acids.
Though most studies examining the health benefits of short-chain fatty acids involve animals, not humans, Robbins said it’s clear that they “play an important role in maintaining the integrity of the gut lining.”
A strong and “healthy gut barrier prevents harmful substances [like toxins or microbes] from entering the bloodstream, potentially reducing inflammation and the risk of gastrointestinal disorders,” she explained.
While regularly eating fermented foods—and the probiotics they contain—has been associated with improved digestion, it’s difficult to prove a direct cause-and-effect relationship.
However, fermented foods themselves may be easier to digest for people with irritable bowel syndrome or related conditions, Pont told Health, because the fermentation process breaks down fermentable carbohydrates—a type of carb that can cause gas and bloating.
For example, one small study found that sourdough bread was more easily digested than bread made with traditional baker’s yeast. A 2021 review also suggested that sourdough may be easier to tolerate for those sensitive to gluten.
That said, if you’re new to regularly eating fermented foods, they can sometimes have the opposite effect—causing bloating, gas, and general stomach discomfort.
“This reaction can occur as your gut adjusts to the influx of probiotics,” Robbins said.
The type of bacteria in fermented foods can also play a role. One type, known as lactic acid bacteria, creates biogenic amines as a byproduct during fermentation. For people with underlying gut issues, these compounds may cause symptoms like diarrhea and stomach cramping.
Fermented foods like kimchi, miso, and tempeh may help rebalance your gut microbiome, support digestion, and improve nutrient absorption. Just keep in mind that not all fermented foods contain probiotics, and introducing them too quickly may lead to stomach discomfort.
If you’re unsure whether certain foods are right for you, check in with a healthcare provider.
