Can fermented foods spike immunity?


Fermented foods have long been an important part of human diet since ages in almost every cuisine, worldwide. Numerous studies have established a clear link between consumption of fermented foods and a boost to the immune system. Let’s examine some of the most popular foods that promise to spruce up our immune system.

Fermented foods are defined as foods or beverages produced through controlled microbial growth, and the conversion of food components through enzymatic action.  In recent years, fermented foods have undergone a surge in popularity due to its positive effect on immunity.

Fermented foods are rich in vitamin c, b, k2, iron and zinc. Fermentation helps in breakdown of nutrients in food, making them more digestible. Fermentation not only enhances the nutritive value of food instead it destroys inhibitors of foods such as phytates, lectins found in pulses. Therefore, consuming fermented foods increases the absorption of nutrients, making them more nutritious.

A diet rich in fermented foods enhances the diversity of gut microbes and decreases susceptibility of illnesses. A wide body of evidence has demonstrated that fermented food shapes the gut microbiome, which can affect the immune system and overall health. 

There is a group of beneficial bacteria called probiotics. Initially they were defined as “Live microbial feed supplements which beneficially affect the host, improving its intestinal microbial balance”. Probiotics are the result of fermentation which play a crucial role in incorporating intestinal microbiota leading to better immunity.


Fermented foods and immunity

Eating foods such as yogurt, kefir, fermented cottage cheese, kimchi and other fermented vegetables, vegetable brine drinks, and kombucha tea led to an increase in overall microbial diversity, with stronger effects from larger servings. 

This provides one of the first examples of how a simple change in diet can reproducibly remodel the microbiota across a cohort of healthy adults.

Studies have found one way that lactic acid bacteria interacts with our bodies. Initially the researchers were investigating proteins on the surface of cells called hydroxycarboxylic acid (HCA) receptors. Most animals have only two types of this receptor but humans and great apes have three. The researchers discovered that a metabolite produced by lactic acid bacteria, D-phenyllactic acid, binds strongly to the third HCA receptor, signaling the immune system with their presence.


Yogurt is a widely used probiotic made from milk, fermented by bacteria. Among the dairy products, yogurt/fermented milks have been the subject of several studies all over the world and different benefits for human health have been reported after their ingestion.


Tempeh is a traditional Indonesian food produced by fermenting boiled and dehulled soybeans with a starter culture of Rhizopus oligosporus fungal species at room temperature for 35–37 hours. It is a good source of protein, iron, manganese, calcium vitamins and minerals. 

Kombucha or Mushroom tea

Kombucha is a Japanese fermented tea made by strains of bacteria, yeast, and sugar. This makes it a good source of probiotics. Kombucha tea is a very good source of antioxidants. Kombucha can improve your immunity but it is not scientifically proven yet.


Kefir is a European fermented drink. The name is derived from the Turkish word keyif, which means feeling good after eating. It is made by adding kefir grains to goat milk or cow milk. Bacteria in the kefir grain ferment the sugar and turn it into kefir. It contains up to 61 bacteria making it a best source of prebiotic. With respect to human health, kefir has antiviral, antimicrobial, and anti-inflammatory potential. It has been shown to inhibit angiotensin-converting enzyme (ACE) levels, cholesterol metabolism, accelerate wound healing, suppress tumour growth, and cause alterations in the immune system.


Fermented cheese is used around the world, with both hard and soft cheeses being made by fermenting milk. Researchers have found that cheese can act as a carrier for probiotic bacteria, widely regarded as beneficial to immune health. Scientists at the University of Turku in Finland have recently discovered that probiotic cheese can tackle the age-related deterioration of the immune system known as immunosenescence. 


Sauerkraut is a German dish brought to Europe from China. In German sauerkraut means sour herb. This dish is eaten with soup and sausages. Sauerkraut is beneficial for gut health and makes the food more digestible. This is simply because sauerkraut enzymes are high in antioxidants, can boost immunity and help decrease levels of ACE2, an enzyme in the cell membrane mostly found in the lungs that is used by coronavirus as an entry point into the body 


Miso means fermented beans in Japanese. Miso is a Japanese fermented food prepared by soyabean, salt and koji or barley with the strain of A. Oryza. Thick paste of seasoning and soyabean is used for sauces, spreads and soup stocks. It contains high amounts of protein, vitamins and minerals. Miso is famous for its umami flavor. Miso is produced by a two-step fermentation process in which first they produce koji and in the second stage koji is mixed with other cultures and salt. Similar to other fermented foods, miso is jam-packed with probiotics, which are a type of beneficial bacteria that live in your digestive tract. However, heating miso is likely to kill these probiotics.


Kimchi originated 3000 years ago. It is a Korean dish of salt, vinegar, garlic, chili, peppers and other spices. Kimchi contains leuconostoc mesenteries which produce dextrin, a substance important to stop the growth of H. Pylori in your body. Kimchi is rich in antioxidants. Early research indicates kimchi may be able to strengthen your immune system. The bacteria that help ferment kimchi have been connected to improved immune function and lower levels of inflammation triggered by diseases.  Vitamin c found in kimchi can also help boost your immune health. 

Sourdough bread

Sourdough bread is fermented by lactobacillus cultures. It is one of the oldest forms of fermentation. Its origin goes back to ancient Egypt in 1500 B.C. Sourdough bread is leavened by wild yeast and lactic acid bacteria making it more nutritious as it contains higher levels of vitamins, minerals, and antioxidants than other bread. It contains lower rates of phytate than regular breads. There are prebiotic features of sourdough found in the non-digestible fibre present – just like Gut Performance. These prebiotics help feed beneficial bacteria, so that they increase in number and diversity. A diverse gut microbiome is positively correlated with a stronger and more supportive immune system. That way, they can do their job – keeping us and our gut happy, healthy and immune.


Pickling is one of the oldest preservation methods of fruits and vegetables. Lactic acid bacteria, bacilli, yeast play a major role in fermentation. Pickling involves preserving food stuff in high acid concentration. Pickles also contain turmeric that is loaded with curcumin that has anti-inflammatory properties which help your body to fight against bacteria and viruses. 


Looking ahead

No single food can improve your immunity. Fermented foods complement your gut health and improve your health with immunity. In fact, Stanford researchers have discovered that a 10-week diet high in fermented foods boosts microbiome diversity and improves immune responses. In times to come, science can help unravel whether microbiota-targeted food could be an avenue for combating the overwhelming rise in chronic inflammatory diseases across the globe.



Dr Anumiita Pathakk, Clinical Nutritionist

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