According to varying sources, the practice of fermenting foods dates back 10 to 12 thousand years.1,2 This practice was mainly used as a way to preserve food, because the process of fermenting dairy, meats, and plant foods leads to the creation of acids, alcohols, and other microbial compounds that prevent the growth of harmful pathogens and bacteria that lead to food spoilage.3 Despite the inception of more efficient forms of modern food preservation, fermented foods, such as yogurt, kimchi, and kombucha, remain popular due to their unique flavors and textures. In addition, fermented foods are still valued for the suggested health benefits they provide.

Fermented foods can make certain nutrients, such as plant proteins in grains, more digestible by partially breaking them down, thus making it easier for the body to access and utilize these nutrients instead of passing them through the digestive tract.4

Recently, fermented foods have gained attention as a source of beneficial bacteria (i.e., probiotics) with the potential to promote gut health. In epidemiological studies, yogurt has been found to prevent metabolic syndrome, obesity, cardiovascular disease, and bladder and colorectal cancers; kimchi has been suggested to reduce the incidence of asthma and atopic dermatitis.3 In clinical studies, both kimchi and yogurt were found to increase insulin sensitivity in participants with obesity and in participants with normal weight.3

If you’re looking to increase your intake of fermented foods for improved gut health, it’s important to note that not all fermented foods are probiotic foods. For example, bacteria and yeast are required to make sourdough breads, but this bacteria doesn’t survive the baking process. Beer and wine are also products of fermentation, which is essential for creation of vitamins and other healthy compounds found in these beverages, but the microbes responsible for this fermentation are removed from the bottled product.³ Additionally, the survival of the healthy microbes  found in kimchi and yogurt depend heavily upon the storage conditions and age of the products by the time they reach consumers.⁵ As a way around this pitfall in probiotic foods, you can easily ferment your own foods at home, taking the guesswork out of the microbial quality of your store-bought fermented foods. Home fermenting is also cost-effective; the money you’ll spend on the necessary supplies and ingredients will yield far more product than it would buying a ready-made product at the store.

SOURCES

1. Fermentation Science: History of Fermentation. Linda Hall Library site. May 17, 2019. https://libguides.lindahall.org/c.php?g=242326&p=1616528. October 2, 2019  
2. Shurtleff W and Ayoyagi A. History of Soybeans and Soyfoods. 2004. http://www.soyinfocenter.com/HSS/fermentation.php. October 2, 2019.
3. Kok CR, Hutkins R. Yogurt and other fermented foods as sources of health-promoting bacteria. Nutrition reviews. 2018 Nov 16;76(Supplement_1):4–15.
4. Nkhata SG, Ayua E, Kamau EH, Shingiro JB. Fermentation and germination improve nutritional value of cereals and legumes through activation of endogenous enzymes. Food Science & Nutrition. 2018 Nov;6(8):2446–2458.
5. Chang JY, Chang HC. Improvements in the quality and shelf life of kimchi by fermentation with the induced bacteriocin producing strain, Leuconostoc citreum GJ7 as a starter. Journal of Food Science. 2010 Mar;75(2):M103–110.