Breathe Life into Your Diet: Eat Fermented Foods

From yogurt in the dairy case to kimchi in condiments, a routine trip to the supermarket resonates with the message that fermented foods are on trend. Even Starbucks has caught the bug, brewing up its own versions of kombucha, an effervescent tea that bubbles with lively organisms. Fermented foods are certainly not new, but they are definitely having a moment. The question is, do they deliver as advertised? 

Long before refrigeration was invented, people fermented food to preserve it. We didn’t understand that living organisms were involved until 1867, when Louis Pasteur identified that yeast and bacteria could convert carbohydrates into by-products that act as preservatives. Now we know these bacteria have a broader skillset. Fermented foods have “functional” value, meaning their health benefits stretch beyond the nutrients they provide.

Here are some of the ways that fermented foods can supersize your diet.

Fermentation makes food easier to digest. Essentially, fermentation jump-starts the process of digestion. By the time you eat fermented foods, their carbs, proteins and fats have already been partially processed, preparing your body to complete the process.

Take dairy products, for instance. Many people are lactose intolerant, which means they can’t digest the natural sugars in milk. But when milk is fermented bacteria gobble up the sugar, producing products like yogurt and kefir, which are better tolerated.

Making dietary changes that expand the range of nutrients you consume is a winning strategy. Bone health provides a case in point. Milk products are one of the best sources of bone-building calcium, as well as the bacterium L. reuteri, a well-known anti-inflammatory that has also been shown to prevent bone loss in older women. 

Eating fermented foods helps your body to utilize and consume nutrients. Fermentation produces helpful bacteria known as probiotics, which help your body to utilize nutrients like calcium, iron, certain B vitamins and vitamin D.

In the process of breaking down food, probiotics also degrade substances known as anti-nutrients, which can interfere with your body’s ability to absorb certain minerals and make foods difficult to digest. However, recent research suggests that anti-nutrients also benefit your health. Nutritional powerhouses like legumes and whole grains contain anti-nutrients and fermentation can make them more tolerable. For instance, by breaking down the anti-nutrient gluten, sourdough fermentation improves its digestibility in people with gluten sensitivity.

Fermentation can increase the nutrients foods provide. When foods are fermented, the levels of certain nutrients may increase. Research shows that fermenting cow’s milk significantly raises its riboflavin (vitamin B2) levels. Friendly bacteria also help your gut flora to manufacture nutrients, like certain B vitamins and vitamin K2. In addition, when the bacteria produced by fermentation reach your gut some produce health-promoting substances like butyrate, a short-chain fatty acid that has been shown to have many health benefits.

Fermented foods support gut health. Among their benefits, fermented foods function like fertilizer for your gut, improving the soil so various types of beneficial bacteria can flourish. Experts now tell us that many diseases can be traced back to a sickly gut. In general terms, a healthy gut has many different types of bacteria with “good guys” running the show. By boosting the numbers of friendly bacteria fermented foods help to keep this microbial ecosystem on track. And if you have tummy troubles or suffer from constipation, some fermented foods, like whole-grain sourdough bread, yogurt and kefir can help. They may also provide nutrients like fiber and polyphenols which encourage the growth of additional health-promoting bacteria.

Fermented foods have a wide range of health benefits. Fermented foods have been shown to be helpful in managing many conditions, from supporting healthy blood sugar levels and keeping “bad” cholesterol and blood pressure under control, to maintaining a healthy weight and boosting mental health. One study linked the consumption of yogurt with better brain function. In laboratory studies, bacteria belonging to the lactobacilli family (particularly abundant in brine-fermented foods like sauerkraut and kimchi) have been shown to boost immunity and improve cognition.

All fermented foods aren’t created equal. Bear in mind that bacteria have distinct benefits. For instance, fermented dairy products provide an abundance of bifidobacteria, which have been linked with improved digestion. Other types of bacteria like the bacillus species are likely to dominate fermented soy products, which appear to have metabolic benefits like lowering cholesterol. This is not to say that foods like miso, natto and tempeh don’t have functional value but rather that they may not be the right choice if your tummy is giving you trouble.

When purchasing fermented foods, it’s important to read the label. You need to make sure that the product provides live microbes because food processing practices may destroy beneficial bacteria.

Speaking of our food supply, some experts are questioning whether following standard protocols to keep pathogens in line may have short-changed us on beneficial bacteria. Known as the hygiene hypothesis this theory questions whether the Westernized world is unnecessarily clean. The current “epidemic” of allergies and autoimmune diseases has been linked with these protective practices. 

Recently, a group of scientists suggested a possible solution: boosting our consumption of fermented foods by adding them to dietary guidelines. We now have Recommended Dietary Allowances for nutrients like carbohydrates and protein. Why not include RDAs for probiotic foods in future directives?  We could feel the love for fermented foods, knowing the quantities we should consume.

For sure the hype is warranted. Now it’s up to you to become informed and eat up.

Selected Resources

Marco, ML. et al.  Should There Be a Recommended Daily Intake of Microbes? The Journal of Nutrition 2020.

Guyonnet, D. Fermented milk containing Bifidobacterium lactis DN-173010 improves gastrointestianal well-being and digestive symptoms in women reporting minor digestive symptoms: a randomised, double-bind, parallel, controlled study. Br. J Nutr, 2009. 

Thomas, R et al. Vitamin D metabolites and the gut microbiome in older men. Nature Communications 2020.

Han, K. et al. Contrasting effects of fresh and fermented kimchi consumption on gut microbiota composition and gene expression related to metabolic syndrome in obese Korean women. Molecular Nutrition and Food Research 2015.

Sonestedt, E.et al. Dairy products and its association with incidence of cardiovascular disease: the Malmo diet and cancer cohort. European Journal of Epidemiology 2011.