The Science Behind Kefir Based Milk Products

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By: Stephanie Jean 

The dairy aisle has expanded tremendously in recent years with an abundance of new products. Whether it be a new Greek yogurt line or a new plant based milk product, the shelves are constantly being updated with emerging items. One of the newest products to line these shelves is a milk based product called kefir. Kefir is an acidic-alcoholic fermented milk product with a slightly acidic taste and creamy consistency, and its journey began in the Balkans in Eastern Europe and in the Caucasus1.  It is likely for kefir to be manufactured from cow, sheep, goat, or buffalo milk1. Recent advancements have been made to produce kefir from soy milk to combat the scarcity, expense, or dietary restraints of animal milk in other countries1.

The production of kefir can be developed from fermenting milk with commercial freeze-dried kefir starter cultures, traditional kefir grains, and the product that remains from the removal of kefir grains1. Kefir grains are a yogurt starter that are white-yellow in color, gelatinous, variable in size, and composed of a microbial symbiotic mixture of lactic acid bacteria, yeast, and acetic acid bacteria that stick to a polysaccharide matrix1. The main polysaccharide in kefir grains is kefiran, which is a heteropolysaccharide composed equally of glucose and galactose1. Kefiran has been proven to improve the viscosity and viscoelastic properties of acid milk gels, and is able to form gels with viscoelastic properties at low temperatures1. Due to this characteristic, kefiran can be used as an additive in fermented products1. In comparison to other polysaccharides, Kefiran has been linked to numerous health related advantages including antitumor, antifungal, and antibacterial properties, epithelium protection, anti-inflammatory, healing, and antioxidant activity1.

Although the consumption of this fermented milk has been related to a selection of health benefits related to its microflora, it is also beneficial due to the presence of metabolic products as organic acids1. Also, kefir cultures have been shown to assimilate cholesterol in milk1. The different process’s in which kefir can lower cholesterol levels is through: (i) the binding and absorption into the cell before it can be absorbed into the body, (ii) producing free and deconjugating bile acids, (iii) inhibiting the enzyme HMG-CoA reductase. This is yet another reason why there is increased interest in the probiotic strains of kefir1.

So, there you have it. A rundown of kefir, which to some (as myself) is definitely going to be useful the next time you are in the grocery store. Reading the nutrition information provided on labels is always good to know more about a product, but it is always useful to back the information up with research based evidence. Especially for newer products that are developing their mark in the aisles of grocery stores!


  1. Prado MR, Blandón LM, Vandenberghe LPS, et al. Milk kefir: composition, microbial cultures, biological activities, and related products. Frontiers in Microbiology. 2015;6:1177. doi:10.3389/fmicb.2015.01177.

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