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7 Fermented Foods to Add to Your Diet

August 18, 2019

By Dr. Mahmoud Ghannoum

It’s probably not news to you that fermented foods are good for you. Fermenting foods is an age-old preservation process that extends the shelf life of foods, as well as their nutritional value. They can dose your body with a wallop of healthy probiotics, the live microorganisms that support your microbiome.

But where to start?

Not only do grocery stores contain a range of fermented products, but shelves full of branded items claiming they contain live bacterial cultures. Consider this your guide to which fermented foods are worth the spend, and which you should pass on.


Consider kefir to be yogurt’s liquidy, tangy cousin. You can drink it, mix it into other foods, or use it in place of milk on top of cereal or granola. Kefir is made by fermenting milk with kefir grains, which contain beneficial bacteria and yeast cultures.

Compared to yogurt, Kefir contains a larger variety of good probiotics — roughly 25 billion colony forming units per one cup versus 2-3 billion in one cup of yogurt. Kefir is also high in protein, making it a good option for vegetarians, and it’s a good source of B vitamins, vitamin K12, and essential amino acids.

As for its probiotic effects? Well, kefir contains up to 61 different strains of bacteria and yeasts, so this fermented food promotes diversity in the gut. It’s known to improve digestive health, and may also act as an anti-inflammatory agent.


Kombucha isn’t technically a food, but a beverage: It’s a type of sweetened black or green tea that uses fermentation to support the growth of good microbes. Kombucha is unique because it’s made from a SCOBY (symbiotic colony of bacteria and yeast), which munches on the sugars in the tea. That process produces organic acids, many vitamins, and healthy bacteria.

Kombucha’s SCOBY includes saccharomyces boulardii, a friendly fungus known to prevent and relieve diarrhea. Research concludes that kombucha contains helpful probiotic bacteria and fungi and supports immune health.

On top of the probiotics Kombucha creates, the chemicals that those probiotics create include antioxidants, which scientists believe play a role in preventing illness and inflammation. Reduced inflammation in your digestive tract is always a good thing.


You probably know miso as the hot, watery soup you get served before the main course at sushi restaurants. Turns out it’s more than just a tasty appetizer. Miso starts as a thick paste made of fermented soybeans, and the starter usually contains Koji (a gut-friendly fungi) and salt.

Not only is miso a source of B vitamins, iron, calcium, potassium, but it’s also a complete protein (from soybeans) and a fermented food that contains a good deal of probiotic bacteria. The variety of bacteria in miso includes one strain that’s been associated with reduced digestive discomfort.

While miso is commonly used to make soup stock (what you get at Japanese restaurants), you can also consume it in the form of a sauce or spread.


Vegans and vegetarians favor tempeh, another fermented food that comes from soybeans, as a healthy source of complete protein. Bacteria and yeast break down the phytic acid in the soybeans, which improves digestion and absorption of the nutrients.

Tempeh also seems to be rich in prebiotics, important fibers that fuel the growth of friendly bacteria in your microbiome. Tempeh is versatile and takes on the flavor of most ingredients it’s combined with, so you can easily add it to your diet in many ways. For example, you can crumble it and add it to a stir-fry, or pan-fry a thin piece and add it to a sandwich.

Fermented vegetables

You may have confused the processes of pickling and fermenting before. Though the two terms are often used interchangeably, they’re quite different: Pickling a food preserves it in brine (very salty water), whereas fermentation preserves a food using bacteria.

Some pickled vegetables are also fermented, so when you’re shopping, look out for labels that say “lacto-fermented” or “raw” or “unpasteurized.” Pro tip: If the jar or package is clear, look out for any bubbles, which is a good sign that there are live cultures in the food.


The sauerkraut you want for gut health will be in a refrigerated aisle because it’s lacto-fermented and contains live, active bacterial cultures. On top of its probiotic benefits, sauerkraut contains an impressive amount of prebiotic fiber, which works together with probiotics to keep your microbiome operating smoothly.

Sauerkraut’s combined prebiotic and probiotic powers help to eliminate constipation, gas, bloating, and cramping. Use sauerkraut as a sandwich topper, mix it into a salad, or eat it on its own as a side dish.


Want something to seriously promote your digestive health? You want kimchi. Another fermented vegetable dish, Kimchi is made when lactic acid bacteria eat away at the sugars in cabbage.

The health benefits of kimchi reach far: Eat kimchi for weight loss, reduced risk of metabolic syndrome, decreased inflammation, and, of course, gut health. The fiber content present in kimchi also helps to regulate bowel movements, effectively preventing constipation.

Not all fermented foods are created equal

Remember to read nutrition facts and ingredient labels before purchasing any fermented foods. Look for labels that include specific names of bacteria or fungi species, and watch out for harmful additives (like too much added sugar in kefir). Also look for labels that say “naturally fermented,” a term that means the manufacturer used live organisms to ferment the food.


BIO: Dr. Mahmoud Ghannoum is one of the world’s leading microbiome researchers and the scientist who named the mycobiome, our body’s fungal community. To read more articles from Dr. Ghannoum go to

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