The Benefits of Fermented Foods

Try these natural probiotic foods for anti-cancer properties, metabolic health and much more.

By Michelle Schoffro Cook


January/February 2017

Woman Eating Yogurt

Yogurt that contains L. casei bacteria can have anti-cancer effects.

Photo by iStock

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The Classic: Yogurt

Everywhere I turn, I see advertisements, commercials and articles about the health benefits of yogurt. And while there is no question that yogurt is one of the most commonly enjoyed fermented foods, it’s important to focus on quality. Many commercial yogurts are loaded with additives including sugar, high-fructose corn syrup, dyes and gums. Choose plain, whole-fat yogurt, ideally made with milk from pasture-raised cows (if buying dairy-based yogurt). Check labels for an indication of the live bacteria present in your carton. Some of the most healthful bacteria include Lactobacillus bulgaricus, L. casei and Streptococcus thermophilus. It’s also very simple to make your own yogurt using a yogurt maker, which are available for about $30. Most research has focused on fermented cow’s milk yogurt, but there’s reason to think that nondairy fermented yogurt offers health benefits, too. Look for yogurts made from the milks of coconut, soy (choose organic only as soy is heavily genetically modified), almonds or cashews. Any of these can be good options, provided they contain live probiotic cultures.  

Here are a few excellent reasons to enjoy yogurt on a regular basis.  

Respiratory Infections:

The British Journal of Nutrition found that the probiotic strain L. casei, found in most yogurt with live cultures, reduces the duration of respiratory infections and severity of nasal congestion linked with these infections among the elderly. 

Gastrointestinal Health:

A study published in the Journal of the American College of Nutrition assessed the effects of yogurt consumption, using a product containing live L. casei cultures, on common infectious diseases in shift workers, including respiratory and gastrointestinal infections. The researchers found that the yogurt consumption could reduce the risk of these infections. Other research published in the World Journal of Gastroenterology showed that yogurt consumption helps fight H. pylori infections. 

Cancer:

Eating yogurt that contains L. casei has been found to have anti-cancer effects in animal studies, according to a study published in the medical journal Immunobiology. The research showed that the probiotic strain blocked tumor development or delayed its growth while improving immune response so the body’s immune system could attack the tumor. Additionally, it reduced the number of blood vessels that fed the tumor. 

Brain Health:

The last thing we probably think of when eating yogurt is how it may be helping our brains. But according to an animal study presented in the journal Nutritional Neuroscience, consuming whey (the liquid byproduct of yogurt production) can actually improve learning and memory. Most yogurt, especially thinner or homemade varieties, tends to contain residual whey. 

Yogurt’s Even Healthier Sister: Kefir

Most people know that yogurt offers health benefits, but fewer have heard about kefir (pronounced ke-FEER), which is a drinkable form of yogurt that offers even greater health benefits. Like yogurt, kefir is a cultured cow’s milk product (although there are nondairy and juice varieties, as well) that has a tart, tangy, sour taste and a slightly bubbly characteristic.  

Kefir comes from the Turkish word keyif which means “good feeling,” probably for the health benefits it offers. This beverage originated in the Caucasus Mountains of Eastern Europe. Thinner in consistency than yogurt, it is made with kefir grains — not actually grains, but a combination of various beneficial bacteria and yeasts. Kefir can also be made with powdered kefir starter, rather than grains. If you have a choice, opt for kefir made with grains, which are richer in probiotics. Like yogurt, many commercial kefir products are heavily sweetened and flavored, so be sure to read labels if you’re buying premade kefir and choose low-sugar options with the fewest possible ingredients.

Here are just a few of kefir’s research-backed health benefits.

Heart and Metabolism Health:

The probiotic Lactobacillus kefiranofaciens has been found to produce a substance known as kefiran. In a study published in the journal Biofactors, researchers found that kefiran from kefir prevented increases in blood pressure, reduced cholesterol levels, and lowered blood sugar levels in animals. 

Fatty Liver and Obesity:

In another study presented in the International Journal of Obesity, researchers assessed the effects of kefir consumption on fatty liver disease. Fatty liver disease is a common problem linked with overweight and obesity, insulin resistance and diabetes. Unfortunately, no medical treatment is effective for this health problem, so researchers attempted to identify natural strategies to improve the condition. They found that daily kefir consumption improved fatty liver syndrome, and also yielded improvements on specific metabolic issues linked with the disease, including increased metabolic rate, improved energy expenditure, and decreased triglyceride and cholesterol in the liver. The scientists concluded that kefir may have the potential for the prevention or treatment of fatty liver disease. 

Cancer:

Probiotics found in kefir also hold promise in the treatment of cancer. One type of probiotic called Lactobacillus kefiri P-IF was shown to help destroy human leukemia cells even when multiple cancer drugs were unable to induce the cancer cell-killing process. The scientists concluded that the novel kefir bacteria “may act as a potential therapy for the treatment of multidrug-resistant leukemia.” 

The Super Healer: Sauerkraut

Sauerkraut — fermented cabbage — isn’t just for hot dogs anymore. In addition to its deliciously tart taste, exciting research showcases the many health benefits of eating sauerkraut (provided it contains live cultures) on a regular basis. Once again, quality is everything when it comes to beneficial bacteria. Many commercial products use shortcuts, pickling products with white vinegar rather than fermentation, and still more are pasteurized with high heat, which kills any beneficial bacteria. Make sure to purchase unpasteurized sauerkraut made with traditional fermentation (check farmers markets or the refrigerator sections of natural food stores), or make your own. Sauerkraut is delicious on its own, atop any kind of sausage, on black bean burgers, or as a side dish to accompany just about any type of meal.  

Here are some of the best reasons to love sauerkraut.  

Antifungal Properties:

What if I told you sauerkraut contains beneficial bacteria that are miniature antifungal manufacturing facilities? It sounds more like science fiction than science fact, but it is true. Some of the probiotics in sauerkraut produce compounds that will kill some species of Candida fungi, which are frequently involved in vaginal or intestinal infections. In research published in the Journal de Mycologie Medicale, scientists found that the probiotics actually produced antifungal compounds to kill Candida

Antioxidant Activity:

A naturally occurring strain of bacteria from fermented cabbage was found to increase the protective effects of antioxidants in animal studies.

Anti-Cancer Benefits:

Some lab studies have suggested that compounds in sauerkraut can affect estrogen levels, and may have a protective effect against the development of breast cancer.  

Prevention of Food Poisoning:

Research in the journal Microbiology and Immunology shows probiotics found in sauerkraut demonstrate antibacterial activity against harmful bacteria, including Salmonella and Shigella. Salmonella can cause food poisoning. Shigella can cause diarrhea, fever and stomach cramps.

The Health-Boosting Condiment: Kimchi

The national dish of Korea, kimchi is a fermented mixture of cabbage, chilies and garlic, with as many variations as there are Koreans who make it. Used as a condiment in Korea, it can be served alongside or on top of any Asian-inspired dish. Like sauerkraut, it makes an excellent sour, palate-cleansing side alongside nearly any dish. A 2013 animal study found that the kimchi probiotic Lactobacillus plantarum may confer protection against the flu by regulating the body’s immunity. Be sure to choose unpasteurized kimchi with a label indicating it “contains live cultures.” Look for it in the refrigerated section of health-food or grocery stores. Organic options are best. Pesticides used in the growing of vegetables can significantly reduce the beneficial bacterial counts in fermented foods. If you’re vegetarian, look for kimchi made without fish sauce.

Here are a few of the health benefits of eating kimchi daily. 

Antioxidant activity:

Scientists have identified a whopping 970 distinct bacterial strains in kimchi. One strain, L. plantarum, is a research-proven antioxidant. Free radicals are unstable molecules that can damage healthy cells and tissues; antioxidants neutralize free radicals, thereby preventing them from damaging healthy cells. In a study published in the online medical journal PLoS One, L. plantarum demonstrated antioxidant activity stronger than other common probiotics. 

Dementia and Memory Loss:

In an animal study published in the Journal of Applied Microbiology, researchers tested probiotics extracted from kimchi to determine whether they have an ability to protect against memory loss. One of the probiotics, known as Lactobacillus pentosus var. plantarum C29, showed potent ability to protect the brain against memory loss. The scientists concluded that kimchi and this probiotic “may be beneficial for dementia.” 

Kombucha: The Healthy Soda 

Kombucha is a beverage believed to have been made in Russia and China for more than 2,000 years, although the exact origin is unknown. 
The bacteria and yeasts that form the kombucha culture form a type of “floating mat” on the surface of the tea from which it is typically made. Little research has been done to test the many anecdotal and folkloric claims of its immune-boosting properties. Regardless, with its mild carbonation, it makes a delicious alternative to sugar- and additive-laden soda. While it is made with sugar, minimal sugar is left in the final kombucha beverage, as the sugar becomes food for the probiotics.

Miso: Built-In Radiation Protection 

Not just for soup, miso’s proven radiation protection means this Japanese staple should warrant further use in our diet. Usually made from fermented soybeans (although rice and chickpea versions also exist), miso is rich in vitamins, minerals, protein, good carbs and probiotics (provided it isn’t heated above 110 degrees). Miso can be added to salad dressings or blended with raw, soaked cashews to make a delicious dip. In animal studies, regular consumption of miso has been linked with protection against radiation injury and the prevention or treatment of lung, liver, breast and colon cancers. 

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Adapted with permission from the bookThe Probiotic Promise: Simple Steps to Heal Your Body from the Inside Outby Michelle Schoffro Cook, Ph.D.