Fermentation: Beyond Probiotic Benefits

November 10, 2013

Thanks to its many advantages, fermentation is back in demand.

If you grew up in the 1970s, you might remember when homemade yogurt became all the rage in the burgeoning health-food scene. As it was with many early health-food trends, yogurt’s healthy image was more anecdotal than backed by science. Today, however, we know that yogurt’s health-promoting benefits are a result of fermentation-the production of live cultures, which have been scientifically proven to promote healthy gut ecology.

The process of fermenting food is an ancient ritual, performed by humans for thousands of years. Its original purpose was to preserve food against spoilage. Many ethnic cultures still eat fermented foods, such as Japanese miso, tempeh, and natto; Korean kimchi; and Mexican pozol. Unfortunately, with the exception of yogurt, fermented foods are not commonly consumed in the Western diet.

Luckily for us, however, a number of food trends are converging to revitalize the art of fermenting foods. The “Do It Yourself” movement has encouraged consumers to make everything at home, such as cheese, jam, beer, and (again!) yogurt. The emergence of the raw food movement has also increased awareness of fermented foods because cultured vegetables are a component of raw food diets. Add to those trends our continued embrace of ethnic cuisine and the food journalist Michael Pollan-inspired shift towards “know what you eat,” and what you get is a culinary climate such that Sandor Katz’s 500-page manifesto called The Art of Fermentation became a New York Times bestseller.

From a chemistry standpoint, fermentation is a simple reaction: using microorganisms, it is the conversion of carbohydrates to alcohols and carbon dioxide or organic acids. Lactobacillus species are the most commonly used microorganisms, used to make foods like yogurt and sauerkraut. In addition to the unique flavors produced by lacto-fermentation, there is also the probiotic benefit of the Lactobacillus species themselves.

But the probiotic benefit is not the only health reason to consume fermented foods and ingredients. Unlike fermented foods, whose main health benefit is their probiotic activity, the health benefits of fermented supplement ingredients are more often a result of the chemical reactions that occur during the fermentation process. For instance, fermentation actually “pre-digests” complex foods by breaking them down into more readily absorbable amino acids and simpler sugars. Certain foods may have excellent nutritional profiles, but are difficult for humans to digest. Cereal grasses are a good example. Cereal grasses are defined as the young grass stage of the wheat, barley, alfalfa, or oat plant. At this young, green stage, the cereal plant is much more nutrient dense than the mature plant, containing many times more B vitamins, minerals, chlorophyll, and antioxidants.  However, the nutrients are encased in cellulose plant cell walls, and humans cannot digest cellulose. Fermentation of cereal grasses is an excellent way to break down cellulose. This is exactly what happens in the “second stomach” of a cow. Ruminants have a separate stomach chamber that breaks down plant materials with the help of
enzymes and bacteria.

Many cultures ferment grains, and studies also show that fermentation of grains increases levels of B vitamins1,2,3,4,5 and lysine.5,6 Fermentation also improves amino acid and vitamin composition2,5 as well as mineral bioaccessibility.4,5,7 Fermenting foods like beans, garlic, and tea has been shown to increase the potency of antioxidant compounds like polyphenols.8,9,10 In some cases, fermentation actually creates unique phytonutrients not present in the raw material.11

Fermentation can also eliminate “anti-nutrients” like phytic acid, a compound found in grains that blocks absorption of minerals,5,12,13,14 and lectins, toxins that interfere with digestion.14,15 Production of kimchi has even been shown to biodegrade pesticides.16

Another example of a beneficial consequence of fermentation is what happens when ginseng root is fermented. It is has been shown that ginsenosides from ginseng are transformed in the intestines of humans by colonic fermentation into an end-stage metabolite called Compound K. Compound K has been proposed to be the most bioavailable metabolite.17 Fermenting ginseng extract actually reproduces the fermentation environment in the colon, thus producing Compound K prior to consumption. Fermented extracts containing Compound K have been shown to have significantly higher and faster absorption in humans compared to non-fermented ginseng.18 Fermented ginseng extracts have also been shown to have the many adaptogenic qualities of ginsenosides, such as strong antioxidant,19 anti-stress,20 hepatoprotective,21 anti-allergy, and anti-inflammatory22 activities, as well as support for healthy glucose and lipid regulation.23

The focus of fermenting supplement ingredients is to promote an environment to maximize these chemical transformations; as such, a controlled fermentation process is necessary. Uncontrolled fermentation can have negative effects, such as loss of nutritional value and palatability as well as potential spoilage. Controlled fermentation, on the other hand, encourages the growth of particular microorganisms only to the point that achieves the desired effects, and then the fermentation is interrupted to stabilize the ingredients.

Fueled by both the increasing popularity of fermented foods and the science that goes beyond the probiotic health benefit of fermentation, the use of fermented supplement ingredients-from cereal grains and grasses, fruits and vegetables, and ginseng to soy-is the latest trend in new product development.

References

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