Milk Kefir: What Is It?

Milk kefir (pronounced kuh-FEAR or KEH-fur) (also known as kefir milk or simply kefir) is a cultured milk drink. It generally contains a wide range of good bacteria as well as beneficial yeasts. These friendly microorganisms form a beneficial and complex community, which varies in terms of species depending on the geographic location in which the kefir is produced. A kefir made in Russia for example, will not have exactly the same friendly yeasts and bacteria as one made in the United States.

Microorganisms that have isolated from kefir include:

Bacteria

Lactobacilli

  • Lactobacillus acidophilus
  • Lactobacillus brevis
  • Lactobacillus casei subspecies rhamnosus
  • Lactobacillus causcasus
  • Lactobacillus fermentum
  • Lactobacillus fructivorans
  • Lactobacillus helveticus
  • Lactobacillus hilgardii
  • Lactobacillus kefir
  • Lactobacillus kefirgranum
  • Lactobacillus lactis
  • Lactobacillus parcasei
  • Lactobacillus parakefir
  • Lactobacillus plantarum
  • Lactobacillus viridescens

Streptococci

  • Streptococcus cremoris
  • Streptococcus diacetylactis
  • Streptococcus thermophilus

Lactococcus

  • Lactococcus lactis subspecies biacetylactis
  • Lactococcus lactis subspecies creomoris
  • Lactococcus lactis subspecies lactis

Leuconostocs

  • Leuconostoc citrovorum
  • Leuconostoc lactis
  • Leuconostoc mesenteroides subsp cremoris
  • Leuconostoc mesenteroides subsp dextrancicum
  • Leuconostoc mesenteroides subsp mesenteroides

Yeasts

Saccharomyces

  • Saccharomyces cerevisae
  • Saccharomyces exigus
  • Saccharomyces florentinus
  • Saccharomyces kefir
  • Saccharomyces turicensis
  • Saccharomyces unisporus

Candida

  • Candida holmii
  • Candida kefir
  • Candida lambica
  • Candida maris
  • Candida pseudotropicalis
  • Candida tenuis
  • Candida valida

  • Torula kefir

Be aware though, this list is far from complete! There are many different strains and species of microorganisms in kefirs – many more than in your probiotic yogurt. Traditionally kefir was made from animal milk. Today many people make dairy-free alternatives such as water kefir, coconut kefir and soya milk kefir.

History of Milk Kefir

Milk Kefir is originates from the Caucasus Mountain Region

Traditionally milk kefir was drunk by the nomadic peoples of the Caucasus mountains, which are located in Russia, Georgia, Azerbaijan and Armenia. These groups discovered that fresh milk carried in leather pouches would occasionally ferment. Over time the kefir milk that had adhered to the insides of these leather pouches was collected, dried and stored for future use. These remnants, which came to be known as kefir grains, were then added to fresh milk to make more supplies of the fermented milk that we know as milk kefir. The kefir grains were recognized for their health-giving and healing properties and were prized by their owners, often being passed down from generation to generation.

In the early 20th century, milk kefir became a subject of Soviet research, which documented many of the health giving properties of this wonderful drink. Since this research is in Russian though, it is not easily accessible to non-Russian speakers.

Today many people around the world drink kefir. It is still particularly popular in Russia and Eastern Europe and is growing in popularity and recognition in the United States. Traditionally the product was home-made but today it is also increasingly possible to buy milk kefir commercially in grocery and health food stores.

Characteristics and Benefits of Milk Kefir

Kefir is similar in consistency to a thick milkshake – it’s thicker than milk but thinner than yogurt. It tastes like natural or plain yogurt, with a slight fizz. If you find it is too sour on its own, you can always sweeten it with fruit or honey.

Milk Kefir is Like a Thick Milkshake in Terms of Consistency

In terms of its benefits, kefir milk contains a wide range of beneficial bacteria and yeasts, which are good for our digestion. Kefir is also rich in vitamins and minerals, specifically vitamins B2 and B12, K, D and A1 as well as magnesium, calcium and phosphorus. It is high in amino acids too, notably tryptophan, which has a calming effect upon our bodies. Kefir is also very easy to digest thanks to the many enzymes that it contains2.

Additionally scientific evidence suggests that drinking kefir can:

  • Improve lactose digestion in people with lactose intolerance 3.

  • Inhibit the growth of tumors4.

  • Assist in eradicating the bacterial infection helicobacter pylori when used in conjunction with triple therapy5.

  • Provide anti-microbial substances such as organic acids (lactic and acetic acid) and hydrogen peroxide, which can inhibit the growth of disease causing bacteria (Gram-positive to a greater extent than Gram-negative)6.

  • Increase the flow of digestive juices and stimulate the wave-like motion of the large intestine known as peristalsis. This latter property may make kefir effective in cases of constipation 7.

As well as these scientific studies documenting the benefit of kefir, there are also many anecdotal reports of the health benefits of drinking kefir. People claim to have used kefir to help them with many different health problems including digestive disorders (such as colitis diarrhea, reflux, leaky gut syndrome food intolerance symptoms, allergies (asthma and eczema), intestinal candida and HIV. At present there is no scientific evidence to support these claims but who knows...kefir may benefit you! It may just help alongside your prescribed treatments.

I Want to Try Milk Kefir – Where Can I Find It?


If you want to try kefir milk, then you have two options. You can either buy it in your grocery or health food store as a ready-made commercial product or you can make your own.

Ready-made or commercial kefir is usually found in the fresh milk or yogurt section of the store and is quite different from homemade kefir. On the plus side it’s very convenient and it is available in plain, low fat, no-fat and flavored varieties. HOWEVER, it’s also far more expensive and sweeter than the homemade milks and in terms of consistency it also tends to be smoother, creamier and thinner.

Often store-bought kefirs also contain a good deal of additional ingredients including flavors, vitamins and sugar – check the label before you buy! Most importantly though these commercial kefirs contain far fewer numbers and varieties of beneficial bacteria and yeasts than your homemade versions. This is partly due to the bottling process, which requires that yeast multiplication be suppressed to prevent the bottles of kefir exploding!!!

Making Kefir

If you are keen to try your hand at making this wonderful milk, have a look at our dedicated page on how to make kefir.

References

1.Foster, K; The Vitamin Content of Kefir; Biochem Z, 1931, 218

2.Alm, L; Effects of Fermentation on Curd Size and Digestibility of Milk Proteins in Vitro of Swedish Fermented Milk Products; Journal of Dairy Science; 1982: 65: 509-514

3.Herztler S.R & Claney S.M; Kefir Improves Lactose Digestion and Tolerance in Adults with Lactose Maldigestion; J Am Diet Assoc; May 2003; Vol 103:5, 582-588

4.Kubo, M et al; Pharmacological Study on Kefir: a Fermented Milk Product in Caucasus. On antitumor activity;Yakugaku Zasshi;1992 Jul;112(7):489-95 (Article in Japanese)

5.Bekar O, et al; Kefir Improves the Efficacy and Tolerability of Triple Therapy in Eradicating Helicobacter pylori; J Med Food.; 2010 Dec 27

6.Garrote, G.L et al; Inhibitory Power of Kefir: the Role of Organic Acids; Journal of Food Protection; 2000; 63: 364-369

7.Hunter, B.T;. Probiotic Foods for Good Health; Basic Health Publications, 2008


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