Signs of an imbalanced environment in the gut include bloating, constipation, acid reflux, skin issues, and poor mental health—but fermented foods can help restore stasis. Here’s how to feed your gut—and reap the benefits.
What are fermented foods?
Fermenting is an age-old practice, first used as a method of food preservation well before fridges had been invented. “Not only does the method extend the shelf life of many foods, but it also improves the digestibility and nutrient availability of foods,” says nutritional therapist Farzanah Nasser.
Foods that are fermented are transformed by beneficial microorganisms such as bacteria and yeast. “During fermentation, these microbes convert natural sugars and starches into organic acids, gases, or alcohol to create distinctive flavors and textures while producing a range of health-promoting compounds,” Nasser adds.
Benefits of fermented foods for gut health
Fermented foods contain probiotics, which are good microbes. According to Nasser, probiotics stay in the gut for five to seven days and do several jobs for our bodies. This includes “supporting the breakdown of foods, helping to extract more nutrients from the food we eat, and even synthesizing vitamins and minerals that we need, such as vitamin B and vitamin K.”
Incorporating lots of fermented foods (which are teeming with microorganisms) into your diet has also been scientifically proven to boost gut microbial diversity, decrease inflammation, and improve immune system function (resulting in a reduced likelihood of developing various diseases).
A 2021 study by researchers at the Stanford School of Medicine found that a 10-week diet incorporating certain fermented foods (more on which later) can “remodel the microbiota across a cohort of healthy adults,” says Justin Sonnenburg, an associate professor of microbiology and immunology at the university.
The research suggests that the more fermented foods we eat, the better, but eating six servings each day (as those taking part in the study did) has been scientifically proven to produce these health benefits.
Who should not eat fermented foods?
While fermented foods can be great for most, err on the side of caution if you have a few of the following conditions.
Histamine intolerance
“Fermented foods are naturally high in histamine and may therefore cause issues such as headaches, flushing, hives, or digestive symptoms,” says Nasser.
Irritable bowel syndrome or small intestine bacterial overgrowth
“Some fermented foods can exacerbate bloating and discomfort with IBS and SIBO,” Nasser explains. If you have any of the aforementioned issues, probiotic supplements may be better tolerated.
The best fermented foods to eat
“If your gut is feeling really out of balance, start slowly,” advises Rhian Stephenson, nutritionist and founder of Artah. “Add a few tablespoons of wild fermented foods a few times a week, and build up your intake slowly.” She recommends avoiding fermented foods that have added sugar, coloring, or lots of vinegar.
Greek yogurt
If you haven’t (knowingly) tried any fermented foods, then Greek yogurt–or indeed any “live” yogurt–can be a good entry point, as well as a great source of protein. Yogurt is created by adding bacteria to milk and leaving it to ferment, and depending on the type you get, it comes in varying levels of thickness. Avoid yoghurts with flavoring or added sugar, look for “live and active cultures” on the label, and ensure it hasn’t been pasteurised for the best wellbeing benefits.
Kefir
Not dissimilar to yogurt, kefir is made by adding kefir grains into milk, and letting them ferment. A tangy delight. Packed with natural berries and fiber, it’s an easy way to boost your gut day to day, but you can also make your own (and add different fruits in) if you prefer.
Sauerkraut
Made from fermented shredded cabbage, sauerkraut has long been popular in German and central European diets for good reason. An easy and tasty addition to any meal, it’s also full of fiber and antioxidants.
Kombucha
Yes, you can drink your ferments too. Kombucha is a great—and tasty—way to boost your microbial diversity, plus it’s also packed with antioxidants. Studies suggest that kombucha consumption has a positive effect on inflammation, liver detoxification, and intestinal dysbiosis, plus it’s delicious.
Kimchi
Hailing from Korea, kimchi is another delicious fermented food that’s made from cabbage, radishes, and/or other vegetables. Studies suggest that it is beneficial for many aspects of health, including a reduced BMI, healthy blood pressure, and easing irritable bowel syndrome.
Miso
Add miso soup to your diet—not only is it delicious, but it is also packed with health benefits. Made from fermented soybeans, salt, and the fungus koji, it contains a probiotic (called A. oryzae) which is said to reduce the risk of inflammatory bowel disease. Don’t like soup? You can also use it as a paste or mix it into dressings for your meals.
Tempeh
Rich in lots of different nutrients, tempeh—made from fermented soybeans—is a favorite amongst vegetarians. As well as being a good source of protein and vitamin B12, it is low in glycemic load, which means it’s great for those trying to manage their blood sugar levels.
Apple cider vinegar
Made up of crushed apples, which are fermented into acetic acid by way of yeast and sugar, apple cider vinegar is a great food ingredient when consumed with the proper guidance. Raw, unfiltered ACV that contains a “mother” (made up of bacteria and yeast) is said to contain the probiotics that are great for our gut.