BY THE OPTIMIST DAILY EDITORIAL TEAM
Fermented foods have been a dietary staple in many cultures for centuries, but in the U.S., they’re only recently starting to get the attention they deserve. From sauerkraut in Germany to kimchi in Korea, many traditional cuisines have long leaned on fermentation not just for flavor but for health.
And now science is catching up.
Research shows that fermented foods support digestive health, enhance immunity, reduce inflammation, and may even improve mood and cognitive function. Unlike fleeting diet trends, this is one wellness practice with centuries of staying power.
According to Amy Burkhart, MD, RD, a physician and registered dietitian specializing in gut health, fermented foods are packed with live microorganisms (also known as probiotics) that interact with our microbiome, the collection of microbes that live in our digestive tract. These beneficial bacteria do a lot more than improve digestion: “They support the gut barrier, aid in nutrient absorption, and can reduce symptoms like bloating or diarrhea,” she explains.
Alma Simmons, RDN, a registered dietitian at the Ohio State University Wexner Medical Center, agrees. “These foods don’t just help with digestion—they reduce inflammation, balance blood sugar, support the immune system, and even lower LDL cholesterol,” she says.
And while probiotics get most of the spotlight, fermented foods also contain byproducts of fermentation called metabolites. These include antioxidants, vitamins, acids, and peptides, which offer their own set of health benefits.
The best fermented foods to try
Not all fermented foods are created equal, but many are widely available and easy to incorporate into your routine. Here are eight worth trying:
1. Plain Greek yogurt
Look for products labeled “live and active cultures.” These typically contain Lactobacillus bulgaricus and Streptococcus thermophilus, which can help balance gut flora, aid digestion, and even make dairy easier to tolerate for people with lactose intolerance. As Dr. Burkhart explains, “People who are lactose intolerant often do fine with fermented dairy like yogurt or kefir.”
2. Kefir
This fermented milk drink offers more microbial diversity than yogurt. According to Simmons, kefir’s symbiotic mix of lactic acid bacteria may support gut balance more broadly and help lower inflammation.
3. Kimchi
This spicy Korean side dish is packed with antioxidants, polyphenols, and lactic acid bacteria. Simmons notes that these nutrients work together to reduce inflammation and improve microbial activity in the gut.
4. Sauerkraut
Beyond being easy to find in most grocery stores, sauerkraut offers compounds that can help protect the gut lining. A 2024 study found that fermented cabbage outperformed raw cabbage in preserving gut barrier function thanks to compounds like lactic acid and gamma-aminobutyric acid.
5. Miso
Made from fermented soybeans, miso delivers bioactive peptides with antimicrobial and antioxidant effects. Bonus: it’s naturally umami-rich and easy to add to soups, dressings, or marinades.
6. Tempeh
Also made from soy, tempeh is typically cooked or pasteurized (which reduces the number of live microbes), but it still contains beneficial fermentation byproducts like peptides and phenols.
7. Sourdough bread
Although baking kills off most live bacteria, the metabolites, especially lactic acid, stick around. These can help inhibit spoilage and preserve freshness longer. Just be sure you’re buying naturally leavened sourdough, not chemically leavened bread.
8. Kombucha
Made from fermented tea, kombucha contains acetic acid and tea polyphenols that deter harmful bacteria. It’s a refreshing and popular option, though sugar content can vary, so make sure to read the label.
Are there any risks to fermented foods?
While fermented foods offer many benefits, they’re not perfect for everyone. People who are immunocompromised may need to avoid raw or unpasteurized fermented foods due to a slightly higher risk of foodborne illness. That said, no documented U.S. cases have linked properly fermented foods to outbreaks, according to a 2024 review in Advances in Nutrition.
Another consideration is histamine sensitivity. Fermentation raises histamine levels, which may trigger headaches, skin reactions, or other symptoms in those who are sensitive. It’s more common among people with ADHD, chronic fatigue syndrome, or who are middle-aged, according to Dr. Burkhart.
Lastly, individuals with IBS or small intestinal bacterial overgrowth (SIBO) may not tolerate fermented foods well at first. This is because their gut bacteria are already imbalanced, so the influx of new microbes can worsen bloating or discomfort.“Start small and ease in slowly,” Dr. Burkhart advises.
How to eat fermented foods the right way
One of the best things about fermented foods is that there’s no one-size-fits-all rule. You can mix and match based on taste, lifestyle, and availability.
That said, here are some helpful tips:
Start slow.
Too much too soon can cause gas or bloating. Begin with small amounts and work up gradually.
Aim for daily variety.
Different fermented foods offer different strains of bacteria. A mix improves microbial diversity.
Look for live cultures.
Choose unpasteurized versions when possible and check for labels like “live and active cultures.”
Keep it simple.
Choose what you enjoy. “Pick something you’re actually going to eat consistently,” Dr. Burkhart says.
If you’re new to fermented foods, try pairing one with a familiar dish. Consider adding kimchi to rice or using miso in soup. The idea is not to overhaul your diet overnight but to make these foods a steady, sustainable part of your routine.
Final thoughts
Fermented foods aren’t a magic cure-all, but when eaten regularly, they can meaningfully support digestion, immunity, and overall health. Whether you start with Greek yogurt, kombucha, or miso, the key is consistency, so choose options that you’ll want to reach for again and again. As Simmons puts it, “There’s no gold medal for eating the ‘best’ fermented food. Just find one that works for you.”
