You may have noticed that fermented foods and drinks are a hot health topic—and for good reason. The helpful bacteria they contain may improve digestion, support immunity, and so much more.

Fermented foods and drinks have long been produced in various cultures. But research is now just trying to play catch-up about all the potential benefits they bestow to people who enjoy them regularly. The general consensus though: Take care of your gut, and in turn, it will take help take care of you.

Here is why bacteria from fermented foods has power when it comes to your health and performance, and the items you should keep on your culinary radar.

What exactly are fermented foods?

Whether you realise it or not, fermentation is a process that’s used to produce some of the world’s most popular foods and beverages. It is an anaerobic process where microorganisms (predominantly yeast and lactic acid bacteria) break down components of foods, such as sugars, into other products including lactic acid and alcohol.

Historically, fermentation has been used to extend the shelf-life of items like vegetables and dairy and alter their flavour. This gave people the option of prolonging the “freshness” of grains, vegetables, and milk that were available to them during different seasons and before the time of refrigerators that now keep spoilage at bay.

Why should you eat fermented foods?

If you’re keen on optimising your nutrition and health, here are four important benefits of wedging more fermented foods into your diet.

1. To improve your gut microbiome

Fermented foods are an excellent source of beneficial bacteria (probiotics) that support your gut microbiota—the trillions of bacteria that reside in our intestines.

After analysing blood and stool samples of healthy adults, Stanford School of Medicine researchers discovered that a 10-week diet high in fermented foods (six servings daily) resulted in measurable improvements in microbiome diversity and decreased markers of inflammation. A high-fermented food diet had more of a beneficial impact on the microbiome of participants than did a high-fibre diet, suggesting it may take longer for the latter to have a noticeable effect.

The evidence also shows that including a variety of fermented foods in the diet can help ensure a well-balanced microbiome and help prevent a bacterial imbalance in your gut called dysbiosis, which can have certain negative health consequences. A modern Western diet relying heavily on ultra-processed foods (and too little on fermented ones) can tilt the balance of your gut microbiota towards unfavourable residents.

In recent years, fostering a healthy microbiome through lifestyle and dietary choices, such as eating more fermented foods, has shown some promising pay-offs for cardiovascular and mental health. Some of these health effects are mediated by bacterial-produced postbiotics, or bioactive metabolites like short-chain fatty acids that can have wide-ranging benefits for the body including lowering inflammation.

Recent research even suggests that the makeup of our microbiome may also play a role in how our muscles adapt and develop in response to exercise. And fertilising your gut with more desirable bacteria via fermented foods may payoff with better digestive functioning during periods of hard training and throughout long races (read: fewer sprints to the nearest port-a-potty).

It’s also worth noting that the good bacteria in fermented foods can help produce a significant percentage of our daily requirement for several vitamins including folate, B6, and vitamin K once they take up residence in our digestive tract.

To date, the literature suggests that probiotic foods (like fermented foods) are still the preferred method of obtaining probiotics rather than relying on supplements.

2. For a nutritional upgrade

Fermentation can make vegetables, grains, and legumes even more nutritious. That’s because plant-based foods typically contain various so-called ‘anti-nutrient’ compounds such as oxalates, phytates, and tannins that can reduce the bioavailability of several important micronutrients, including calcium and iron. In other words, you won’t be able to use the full amount of nutrients in this food. However, research shows that the fermentation process can improve the nutrient bioavailability of plant foods.

For instance, fermentation increases mineral bioavailability by producing an enzyme that degrades the phytic acids in plant foods. According to research, this may increase the amount of calcium, iron, and zinc you can absorb from foods, such as the vegetables used to make kimchi or the soybeans that make tempeh. During fermentation, pH is reduced, which enhances the absorption of plant-based iron because of its conversion to the more readily absorbed ferrous iron.

Plant protein digestibility also increases during the fermentation process and there is also some evidence that inoculating foods with starter cultures (that’s how you ferment foods) can boost levels of antioxidants.

This makes the various guises of fermented foods a good way to help runners meet their overall nutrition needs to better support training and overall health. And these are nutritional benefits that remain even if a fermented product like tempeh or sourdough is heated, which will likely to kill off most of the probiotics.

3. To improve your digestion

Microorganisms used in fermentation can produce a range of enzymes that can dismantle fats, carbohydrates, and proteins into simple digestible constituents, making them easier to digest. This means the probiotics found in fermented foods can reduce many of the gastrointestinal symptoms, including bloating, diarrhea, and constipation that some people experience when eating certain plant foods like cruciferous veggies and soy.

For instance, fermentation breaks down the non-digestive oligosaccharides (a type of carbohydrate) in soy foods so you may experience fewer gassy side effects when eating tempeh compared to tofu. The process has also been shown to lower FODMAPs in several foods. These are short-chain carbs that are resistant to digestion and the cause of stomach woes for some people.

During fermentation, bacteria also feed on and reduce levels of the lactose that occurs naturally in dairy. (Bacteria that ferment milk break down much of the lactose into easier-to-digest lactic acid and lactate.) This is why many people who are intolerant to lactose will find fermented dairy including yoghurt and kefir better tolerated than milk and other non-fermented dairies.

In fact, a study in the Journal of the American Dietetic Association found that consuming kefir resulted in much fewer digestive issues including flatulence, diarrhea, and abdominal pain in those with lactose intolerance.

4. For making new and improved proteins

During fermentation, bacterial-derived enzymes breakdown the protein in food into smaller fragments called peptides that are biologically active and can result in certain health advantages once eaten. This includes lowering blood pressure and inflammation. Perhaps, this could be a reason why consistent yoghurt consumption has been linked to a lower risk for hypertension.

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Fermented Foods to Add to Your Diet

Including a variety of bug-laced foods in your diet is a smart move for optimal health benefits. Here are the not-so-fresh foods to add to your grocery list.

A note on eating too many fermented foods too quickly: If you’re not used to consuming fermented foods, introduce them slowly into your diet (just like you would fibre-rich foods!) to help side-step some potential GI symptoms, such as gas and bloating.

This is sage advice especially before gearing up for a run. Each person will need to find their initial tolerance and then build up from there. Also, to keep your overall sodium intake within a healthy range, offset some of the higher sodium fermented foods, like miso and kimchi, with lower sodium options, including tempeh and yogurt.

1. Apple Cider Vinegar

Vinegar that is raw and contains the “mother” floating within it can be considered fermented and likely contains some probiotics. Use it in your salad dressings and try switchel (a mix of apple cider vinegar, honey, ginger, and water) for an ultra-refreshing vinegary drink.

2. Kombucha

This slightly fizzy fermented tea is a good alternative to soda and a way to help stay hydrated. The drink is often flavoured with herbs or fruit. Just watch out for sugar numbers. Stick to a drink with no more than 8 grams of sugar per serving.

3. Kefir

This fermented dairy drink is made using kefir grains (a combination of bacteria and yeast). The result? A probiotic-laced tangy dairy that’s thinner in consistency than yogurt. Find it in the dairy case and use it as a base for smoothies or a swap for buttermilk in pancakes.

4. Kimchi

There are hundreds of varieties of this Korean fiery fermented side dish, commonly made from a base of napa cabbage, radish, scallions, and spices. Use it atop scrambled eggs, burgers, sandwiches, and tacos.

5. Miso

Made from cooked whole soybeans, which are combined with koji (a bacteria starter), salt, and rice or barley. The longer the ferment time the darker the colour, and the bolder the flavour. Try whisking the umami-rich paste into salad dressings or stir a tablespoon or two into mashed potatoes. Stirred into warm water for a healthy electrolyte recovery drink too.

6. Natto

Perhaps the funkiest of the bunch, natto is a popular food in Japan consisting of soybeans that are fermented into a mass of beans with a sticky, slimy texture.

7. Sauerkraut

This traditional Eastern European “sour cabbage” can jazz up your lunch sandwiches as well as tacos, grain salads, and burgers. To guarantee it still has probiotics, look for the words “unpasteurised” or “raw” on labels, and make sure it comes chilled. The kind sold as shelf-stable in cans or jars have been heated which degrades the probiotics.

8. Sourdough bread

Its quintessential tang hails from the old-school baking method of using a bacteria- and yeast-rich starter to kickstart fermentation. Some evidence suggests the bread is easier to digest for certain people by reducing gluten levels. If not baking your own, seek out authentic loaves from artisanal bakers.

9. Tempeh

Produced when whole soybeans are soaked, cooked, left to ferment, and then pressed into a protein-rich firm meaty patty with an earthy, nutty flavour. You can marinate and grill slabs like steak, or crumble and use tempeh as a substitute for ground meat in chilli, pasta sauces, and tacos.

10. Yogurt

Made from fermenting milk (or a non-dairy alternative) with a starter culture of bacteria. Yoghurt labeled with the “live and active cultures” seal guarantees 100 million probiotic cultures per gram at manufacturing time. Opt for Greek or Skyr and you’ll net about twice as much protein, compared to regular varieties.

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