KEFIR

Kefir is a natural probiotic, rightly considered a superfood due to its high content of vitamins, minerals and essential amino acids. It is best known for its beneficial effect on intestinal microflora, but it also improves digestion and lactose tolerance, has antibacterial, anti-inflammatory and antioxidant properties, lowers cholesterol, controls plasma glucose, regulates blood pressure, fights cancer cells and even promotes healing.

Kefir, the oldest known probiotic

Kief is a Turkish word meaning “well-being”, which aptly describes the advantages of drinking kefir indicates a  link to its probiotic properties and health benefits. The drink is believed to have originated in the Caucasus Mountains, where tribes traditionally passed on kefir grains from generation to generation as far back as 2000 BC, believing that the grains had been given to them by the prophet Muhammad and thus blessed them with exceptional health. Because these tribes are renowned for their longevity, kefir has been nicknamed “the drink of the centenarians of the Caucasus”. Although scientists still do not know how the kefir grains were formed, it is known that the traditional way of making kefir was by adding kefir grains to milk stored in a sealed leather bag made of goat or sheep skin, which was used to stir the drink until the milk fermented into kefir.

Dr. Elie Metchnikoff, Russian immunologist

How to prolong life is a question that was of particular interest to Dr Elie Metchnikoff, a Russian immunologist and Nobel Prize winner, who claimed that the longevity of the Caucasians was due to the human-friendly bacteria in kefir, which fights harmful micro-organisms in the digestive tract and thus prevents disease. After the publication of his book Life Extension in 1907, the All-Russian Medical Association decided to use milk kefir as a cure for a wide range of ailments, including indigestion, cancer, atherosclerosis and tuberculosis. Kefir is now widespread throughout the world and continues to be of interest to researchers who are discovering new uses for kefir in medicine every day.

Kefir production method

Kefir can be produced in two ways: traditional or industrial.

Kefir is traditionally made from a combination of kefir grains and cow’s, goat’s or sheep’s milk. These grains, also called live kefir cultures, are full of lactic acid and acetic acid bacteria and yeasts that carry out the fermentation process and turn the milk into kefir. During fermentation, the structure of the milk is completely changed, resulting in a probiotic drink with beneficial effects on the gut and health.

Kefir made using the industrial method is widespread, as it allows standardisation of the product and facilitates production and transport. The main difference is that the industrial method uses pure cultures of micro-organisms isolated from kefir grains. While their composition is similar to that of kefir grains, the effect of complex linkages, interrelationships and interactions is lost. The components produced are not exactly the same as those in traditional kefir, which means that the nutritional value is also altered, and the functional properties of kefir are at least partially lost.

“The use of kefir grains releases a number of compounds that are not present in kefir produced using pure cultures. There is also a problem with labelling the product as kefir, as it does not have all the characteristics of traditional kefir and is in fact misleading to consumers,” warns the NIJZ.

Kefir grains, the basis of kefir

Kefir grains, which look like cauliflower, are white-yellow, gelatinous and vary in size (from 0.3 to 3.5 cm in diameter). They consist of a symbiotic mixture of lactic acid bacteria, yeasts, fungi, acetic acid bacteria and polysaccharides. The main polysaccharide is kefiran, which is mainly produced by Lactobacillus kefiranofaciens and consists of equal parts of glucose and galactose. Compared to other polysaccharides, kefiran has remarkable advantages as it is antitumour, antifungal and antibacterial, has the ability to immunomodulate or protect the epithelium, prevents inflammation, has antioxidant properties and aids in healing. 

Kefir contains considerably more beneficial micro-organisms than other fermented dairy products such as yoghurt or sour milk. While yoghurt contains only a few bacteria kefir grains can contain up to 25 different probiotic cultures. The greater variety of beneficial probiotic organisms leads to a more diverse and rich microflora that is more resistant to harmful bacteria and viruses, which is why kefir has the greatest potential to protect the immune system compared to other probiotic products.

How is kefir fermented?

Lactobacillus, or lactobacilli, play a key role in the fermentation process, breaking down milk sugar into lactic acid, which gives kefir its characteristic sour taste. As a result, kefir is also suitable for people with lactose intolerance due to its low milk sugar or lactose content. Yeasts also play an important role in the fermentation process, breaking down lactose into carbon dioxide and ethanol. In addition, fermentation breaks down proteins into their basic building blocks, amino acids, which are essential for a strong immune system and the proper functioning of many processes in the body. During the fermentation process, milk fat is also broken down to free fatty acids. As a result, kefir is easier to digest and has a higher nutritional value compared to milk.