For millennia, fermented foods have been a part of human diets in various cultures around the world for their unique flavor, health benefits, and extended shelf-life. Fermented foods offer a variety of health benefits, most notably their gut-supporting properties. Research has shown that fermented foods also provide a variety of benefits beyond gut health, including reduced type 2 diabetes and cardiovascular risk. (27)

What is fermentation?

Fermentation is a chemical process in which carbohydrates are converted to acid or alcohol in an anaerobic (absence of oxygen) environment. Microorganisms, such as bacteria and yeast, are necessary for this process. Yeast performs fermentation by consuming sugar and producing alcohol as a byproduct. Bacteria assists by converting carbohydrates into lactic acid, which lowers the pH of the food, lengthens shelf-life, and enhances flavor. (19)(23)

Cultures around the world have used the fermentation process for thousands of years for its health benefits and food preservation effects. For example, sauerkraut, a type of fermented cabbage, originates back to the fourth century B.C. and still continues to be widely consumed in Germany, Europe, and the United States. (9) Fermented foods and beverages account for nearly one-third of the world’s food intake. (6)

Asian countries have consumed fermented fish, grains, legumes, and vegetables throughout history. (31) Japanese adults have a decreased risk of developing type 2 diabetes compared to Western countries, a trend associated with the population’s regular consumption of fermented soy products, such as miso and natto. (27)(24)

Fermentation should not be confused with pickling. Although fermentation is a type of pickling, general pickling does not produce the same health benefits. Pickling involves soaking food, such as onion or cucumber, in an acidic brine, whereas fermenting depends on the actions of yeast and bacteria to break down the starches in the food. (27)

Health benefits of fermented foods

Below are some of the evidence-based health benefits of consuming fermented products.

Improves gastrointestinal health

Fermented foods and beverages contain beneficial live bacteria, commonly known as probiotics. The gut hosts trillions of microbes responsible for breaking down food, protecting the body from harmful pathogens, and supporting the immune system. Disease, stress, and certain medications (e.g., antibiotics) can disrupt the gut microbiome. Probiotics, like those found in fermented foods, may help restore balance in the gut. (27)

Fermenting certain foods may also result in a reduction of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs). FODMAPs are poorly absorbed in the small intestine and are fermented by bacteria in the large intestine, which may contribute to gas, bloating, diarrhea, and constipation. Foods high in FODMAPs may be problematic for individuals with irritable bowel syndrome (IBS) as they can induce or aggravate intestinal symptoms for these individuals. (21)

Furthermore, research has shown that several yeast strains, particularly S. cerevisiae and T. delbrueckii, may degrade up to 90% of fructans, a type of oligosaccharide, in wheat bread after proofing (fermenting) for four hours. (10)(39) This is good news for individuals with IBS who may not typically tolerate wheat in their diet.

Helps support healthy immune function

Approximately 70% of your body’s immune cells reside in the gut. Fermented foods support the immune system by maintaining a healthy gut microbiome. (35)

Probiotics found in fermented foods may lessen the duration of acute upper respiratory infections such as the common cold. (12) Fermentation also increases antioxidant activity in foods, which protect immune cells from oxidative stress. (15)

Additionally, several studies have shown that the bacteria in kefir, a fermented dairy beverage, may support the immune system by stimulating immune cells, such as macrophages, needed to fight infection. (36)(1) Consuming kefir may also help alleviate symptoms, such as airway inflammation, associated with allergies and asthma. (5)(14)

Increases nutrient content and bioavailability

The fermentation process increases the bioavailability of some dietary nutrients, including B vitamins, calcium, iron, magnesium, and zinc. This is believed to be a result of a reduction in phytic acid, a compound found in plants that may impair nutrient absorption. (25)(30) Fermentation also breaks down cell walls of plant foods, making it easier for your body to digest and absorb nutrients. (37)(25)

Furthermore, fermentation may reduce or remove sugars from some foods. The process involved in making kombucha, a fermented tea, requires the use of sugar and a biofilm of bacteria and yeast called a scoby. Sugar feeds the scoby, and as the kombucha ferments, sugar concentration in the tea decreases. (11)

May lower the risk of heart disease

Regularly consuming fermented dairy products, such as kefir and yogurt, may decrease your risk of developing cardiovascular disease. (38) Research has shown that fermented dairy may increase serum HDL levels (healthy cholesterol) and may play a role in preventing hypertension (high blood pressure). (33)(32)(18)

One study also showed that consuming large amounts (210 g per day) of fermented cabbage, known as kimchi, for seven days significantly reduced serum total cholesterol and LDL levels (unhealthy cholesterol) compared to the group that consumed only small amounts (15 g per day). (7)

May help prevent and manage type 2 diabetes

Certain fermented foods may positively impact blood glucose levels and contribute to the management of type 2 diabetes. The probiotics found in fermented products may reduce the inflammatory response in individuals with diabetes, resulting in improved insulin sensitivity. (26)(29)

Research has shown that consumption of fermented products, such as kefir and sauerkraut, may complement an existing treatment plan for diabetes management. One study demonstrated that daily consumption of kefir significantly reduced hemoglobin A1c (HbA1c), an indicator of blood sugar control. (29)(26) Animal studies suggest that kombucha, a fermented tea, may also reduce hemoglobin A1c. (29)

Furthermore, kimchi may be effective in reducing fasting blood sugar, which is elevated in type 2 diabetes. One study determined that consuming large servings of kimchi significantly reduces fasting blood sugar by 6.96%. (7)

May influence mood

There appears to be a theoretical link between mental health and the consumption of fermented foods. Improved bioavailability of nutrients in fermented foods, particularly B vitamins such as folate and B12, may improve mood and reduce symptoms of depression and anxiety. (3)(8)(30) Folate and vitamin B12 are necessary for serotonin and dopamine production, which are mood-regulating neurotransmitters. (22)(34)

Furthermore, the positive impact fermented foods have on the health of the intestinal microbiota may also improve vitamin D levels. (28)(16) Vitamin D deficiency is associated with symptoms of depression and anxiety in certain individuals. (17)(2)

Did you know?
Research has shown that kefir, a fermented dairy beverage, contains more than 50 strains of bacteria and yeast, which promote the growth of healthy microbes in the gut. (5)(20)

Types of fermented foods and beverages

Fermented products are widely available and can be found in most grocery stores. Some common fermented foods and beverages include:

  • Kefir: yogurt-like dairy beverage
  • Kimchi: seasoned, fermented cabbage common in Korean cuisine
  • Kombucha: probiotic-rich tea
  • Miso: fermented soybean paste
  • Sauerkraut: fermented cabbage
  • Tempeh: fermented soybean cake
  • Yogurt: fermented milk (27)
Image of fermented foods

Fermented foods host several strains of probiotics, which may improve gut health by restoring gut microbiota. (13)

Adding fermented foods to your diet

Current dietary guidelines don’t explicitly state recommendations for fermented foods; however, incorporating these foods into your diet on a daily basis may benefit your health. (4) Adding fermented products into your diet is simple — it can be as easy as adding sauerkraut to your sandwich or drinking kefir with your breakfast. Enjoy a variety of fermented foods and beverages and find the products you like best.

Keep in mind that not all fermented foods contain probiotics. Some fermented products, such as beer and wine, undergo a process that eliminates any remaining microorganisms. Furthermore, heating fermented foods can deactivate microorganisms. (27)

There currently is no regulatory requirement for companies to indicate microbial levels on their products; however, many brands voluntarily provide this information. With the rising popularity of fermented foods, more companies are choosing to be transparent about their products via food labels. When shopping for fermented products, search for products that contain live microorganisms. (27) Many fermented foods, including kombucha and sauerkraut, release bubbles when opened, which is a good indicator that the product contains live organisms. (9)

The bottom line

Consuming fermented foods and beverages is a simple and practical way to add more probiotics to your diet. Regular consumption of fermented products, such as yogurt and kombucha, may improve digestion, lower your risk for heart disease and diabetes, and support your immune system. (21)

Fullscript simplifies supplement dispensing

Create your dispensary today I'm a patient
  1. Adiloğlu, A. K., Gönülateş, N., Işler, M., & Senol, A. (2013). The effect of kefir consumption on human immune system: A cytokine study. Mikrobiyoloji Bulteni, 47(2), 273–281.
  2. Armstrong, D. J., Meenagh, G. K., Bickle, I., Lee, A. S. H., Curran, E.-S., & Finch, M. B. (2006). Vitamin D deficiency is associated with anxiety and depression in fibromyalgia. Clinical Rheumatology, 26(4), 551–554.
  3. Aslam, H., Green, J., Jacka, F. N., Collier, F., Berk, M., Pasco, J., & Dawson, S. L. (2018). Fermented foods, the gut and mental health: a mechanistic overview with implications for depression and anxiety. Nutritional Neuroscience, 1–13.
  4. Bell, V., Ferrão, J., & Fernandes, T. (2017). Nutritional guidelines and fermented food frameworks. Foods, 6(8), 65.
  5. Bourrie, B. C. T., Willing, B. P., & Cotter, P. D. (2016). The microbiota and health promoting characteristics of the fermented beverage kefir. Frontiers in Microbiology, 7, 647.
  6. Campbell-Platt, G. (1994). Fermented foods — a world perspective. Food Research International, 27(3), 253–257.
  7. Choi, I. H., Noh, J. S., Han, J.-S., Kim, H. J., Han, E.-S., & Song, Y. O. (2013). Kimchi, a fermented vegetable, improves serum lipid profiles in healthy young adults: Randomized clinical trial. Journal of Medicinal Food, 16(3), 223–229.
  8. D’Aimmo, M. R., Mattarelli, P., Biavati, B., Carlsson, N. G., & Andlid, T. (2012). The potential of bifidobacteria as a source of natural folate. Journal of Applied Microbiology, 112(5), 975–984.
  9. Dimidi, E., Cox, S. R., Rossi, M., & Whelan, K. (2019). Fermented foods: Definitions and characteristics, impact on the gut microbiota and effects on gastrointestinal health and disease. Nutrients, 11(8), 1806.
  10. Fraberger, V., Call, L.-M., Domig, K., & D’Amico, S. (2018). Applicability of yeast fermentation to reduce fructans and other FODMAPs. Nutrients, 10(9), 1247.
  11. Gaggìa, F., Baffoni, L., Galiano, M., Nielsen, D., Jakobsen, R., Castro-Mejía, J., … Di Gioia, D. (2018). Kombucha beverage from green, black and rooibos teas: A comparative study looking at microbiology, chemistry and antioxidant activity. Nutrients, 11(1), 1.
  12. Guillemard, E., Tondu, F., Lacoin, F., & Schrezenmeir, J. (2009). Consumption of a fermented dairy product containing the probiotic Lactobacillus casei DN-114 001 reduces the duration of respiratory infections in the elderly in a randomised controlled trial. British Journal of Nutrition, 103(1), 58–68.
  13. Hemarajata, P., & Versalovic, J. (2012). Effects of probiotics on gut microbiota: mechanisms of intestinal immunomodulation and neuromodulation. Therapeutic Advances in Gastroenterology, 6(1), 39–51.
  14. Hong, W.-S., Chen, Y.-P., Dai, T.-Y., Huang, I.-N., & Chen, M.-J. (2011). Effect of heat-inactivated kefir-isolated Lactobacillus kefiranofaciens M1 on preventing an allergic airway response in mice. Journal of Agricultural and Food Chemistry, 59(16), 9022–9031.
  15. Hur, S. J., Lee, S. Y., Kim, Y.-C., Choi, I., & Kim, G.-B. (2014). Effect of fermentation on the antioxidant activity in plant-based foods. Food Chemistry, 160, 346–356.
  16. Jones, M. L., Martoni, C. J., & Prakash, S. (2013). Oral supplementation with probiotic L. reuteri NCIMB 30242 increases mean circulating 25-Hydroxyvitamin D: A post hoc analysis of a randomized controlled trial. The Journal of Clinical Endocrinology & Metabolism, 98(7), 2944–2951.
  17. Jorde, R., Sneve, M., Figenschau, Y., Svartberg, J., & Waterloo, K. (2008). Effects of vitamin D supplementation on symptoms of depression in overweight and obese subjects: randomized double blind trial. Journal of Internal Medicine, 264(6), 599–609.
  18. Kiessling, G., Schneider, J., & Jahreis, G. (2002). Long-term consumption of fermented dairy products over 6 months increases HDL cholesterol. European Journal of Clinical Nutrition, 56(9), 843–849.
  19. Kim, B., Hong, V. M., Yang, J., Hyun, H., Im, J. J., Hwang, J., … Kim, J. E. (2016). A review of fermented foods with beneficial effects on brain and cognitive function. Preventive Nutrition and Food Science, 21(4), 297–309.
  20. Kim, D.-H., Jeong, D., Kim, H., & Seo, K.-H. (2018). Modern perspectives on the health benefits of kefir in next generation sequencing era: Improvement of the host gut microbiota. Critical Reviews in Food Science and Nutrition, 59(11), 1782–1793.
  21. Melini, F., Melini, V., Luziatelli, F., Ficca, A. G., & Ruzzi, M. (2019). Health-promoting components in fermented foods: An up-to-date systematic review. Nutrients, 11(5), 1189.
  22. Miller, A. L. (2008). The methylation, neurotransmitter, and antioxidant connections between folate and depression. Altern Med Rev, 13(3), 216–226.
  23. National Research Council (US) Panel on the Applications of Biotechnology to Traditional Fermented Foods. (1992). Applications of biotechnology to fermented foods: Report of an ad hoc panel of the board on science and technology for international development.
  24. Neville, S. E., Boye, K. S., Montgomery, W. S., Iwamoto, K., Okamura, M., & Hayes, R. P. (2009). Diabetes in Japan: a review of disease burden and approaches to treatment. Diabetes/Metabolism Research and Reviews, 25(8), 705–716.
  25. Nkhata, S. G., Ayua, E., Kamau, E. H., & Shingiro, J.-B. (2018). Fermentation and germination improve nutritional value of cereals and legumes through activation of endogenous enzymes. Food Science & Nutrition, 6(8), 2446–2458. Ostadrahimi, A., Taghizadeh, A., Mobasseri, M., Farrin, N., Payahoo, L., Beyramalipoor Gheshlaghi, Z., & Vahedjabbari, M. (2015). Effect of probiotic fermented milk (kefir) on glycemic control and lipid profile in type 2 diabetic patients: a randomized double-blind placebo-controlled clinical trial. Iranian Journal of Public Health, 44(2), 228–237.
  26. Rezac, S., Kok, C. R., Heermann, M., & Hutkins, R. (2018). Fermented foods as a dietary source of live organisms. Frontiers in Microbiology, 9, 1785.
  27. Selhub, E. M., Logan, A. C., & Bested, A. C. (2014). Fermented foods, microbiota, and mental health: ancient practice meets nutritional psychiatry. Journal of Physiological Anthropology, 33(1), 2.
  28. Sivamaruthi, B., Kesika, P., Prasanth, M., & Chaiyasut, C. (2018). A mini review on antidiabetic properties of fermented foods. Nutrients, 10(12), 1973.
  29. Suri, D. J., & Tanumihardjo, S. A. (2016). Effects of different processing methods on the micronutrient and phytochemical contents of maize: From A to Z. Comprehensive Reviews in Food Science and Food Safety, 15(5), 912–926.
  30. Tamang, J. P., Cotter, P. D., Endo, A., Han, N. S., Kort, R., Liu, S. Q., … Hutkins, R. (2020). Fermented foods in a global age: East meets west. Comprehensive Reviews in Food Science and Food Safety, 19(1), 184–217.
  31. Tapsell, L. C. (2015). Fermented dairy food and CVD risk. British Journal of Nutrition, 113(S2), S131–S135.
  32. Tholstrup, T. (2006). Dairy products and cardiovascular disease. Current Opinion in Internal Medicine, 5(2), 140–149.
  33. Valizadeh, N., & Valizadeh, M. (2011). Obsessive compulsive disorder as early manifestation of B12 deficiency. Indian Journal of Psychological Medicine, 33(2), 203–204.
  34. Vighi, G., Marcucci, F., Sensi, L., Di Cara, G., & Frati, F. (2008). Allergy and the gastrointestinal system. Clinical & Experimental Immunology, 153, 3–6.
  35. Vinderola, G., Perdigon, G., Duarte, J., Thangavel, D., Farnworth, E., & Matar, C. (2006). Effects of kefir fractions on innate immunity. Immunobiology, 211(3), 149–156.
  36. Xiang, H., Sun-Waterhouse, D., Waterhouse, G. I. N., Cui, C., & Ruan, Z. (2019). Fermentation-enabled wellness foods: A fresh perspective. Food Science and Human Wellness, 8(3), 203–243.
  37. Zhang, K., Chen, X., Zhang, L., & Deng, Z. (2019). Fermented dairy foods intake and risk of cardiovascular diseases: A meta-analysis of cohort studies. Critical Reviews in Food Science and Nutrition, 60(7), 1189–1194.
  38. Ziegler, J. U., Steiner, D., Longin, C. F. H., Würschum, T., Schweiggert, R. M., & Carle, R. (2016). Wheat and the irritable bowel syndrome – FODMAP levels of modern and ancient species and their retention during bread making. Journal of Functional Foods, 25, 257–266.