Advances in the study of the multifunctional bioactivity of kefir | Avances en el estudio de la bioactividad multifuncional del kéfir

Kefir is a fermented milk beverage with multifunctional bioactivity. This beverage is made by inoculating kefir grains in milk, which also represents a source of compounds with biological activity. The microbiota of kefir grains consists mainly of yeasts, bifidobacterium, and lactic and acetic acid bacteria. These symbiotic microorganisms generate metabolites such as exopolysaccharides, organic acids and bacteriocins; furthermore, they release peptides with potential bioactivity. The resulting peptide sequences may have chemical structures similar to endogenous peptides which act in the body as hormones, neurotransmitters, or regulators. Recent in vitro and in vivo studies have shown that kefir has multiple bioactivities, e.g., antioxidant, antihypertensive, hypocholesterolemic, antimicrobial, anti-inflammatory, hypoglycemic and antitumoral. This review presents the advances related to microbiota composition, health benefits and perspectives of kefir studies.