Kefir: a symbiotic yeasts-bacteria community with alleged healthy capabilities

Rev Iberoam Micol. 2006 Jun;23(2):67-74. doi: 10.1016/s1130-1406(06)70016-x.


Kefir is a fermented milk beverage. The milk fermentation is achieved by the of kefir grains, a cluster of microorganisms held together by a polysaccharide matrix named kefiran. Kefir grains are an example of symbiosis between yeast and bacteria. They have been used over years to produce kefir, a fermented beverage that is consumed all over the world, although its origin is Caucasian. A vast variety of different species of organisms forming the kefir grains, comprising yeast and bacteria, have been isolated and identified. Kefir is a probiotic food. Probiotics have shown to be beneficial to health, being presently of great interest to the food industry. Kefir has been accredited with antibacterial, antifungal and antitumoural activities among other beneficial attributes. This review includes a critical revision of the microbiological composition of kefir along with its beneficial properties to human health.

MeSH terms

  • Animals
  • Bacterial Infections / diet therapy
  • Cattle
  • Cholesterol / metabolism
  • Cultured Milk Products / microbiology*
  • DNA Repair
  • Digestive System Diseases / diet therapy
  • Digestive System Diseases / prevention & control
  • Drug Screening Assays, Antitumor
  • Fermentation
  • Food Industry / methods
  • Food Microbiology
  • Food, Organic / microbiology*
  • Fungi / isolation & purification
  • Fungi / physiology*
  • Goats
  • Humans
  • Immune System / drug effects
  • Industrial Microbiology
  • Lactobacillus / physiology*
  • Mycoses / diet therapy
  • Neoplasms / diet therapy
  • Neoplasms / drug therapy
  • Polysaccharides / biosynthesis
  • Polysaccharides / therapeutic use
  • Probiotics / therapeutic use*
  • Symbiosis
  • Yogurt


  • Polysaccharides
  • kefir grain polysaccharide
  • Cholesterol