The microbiota related to kefir intake, as occurs with other probiotics, are a combination of many factors as actions of bacteriocins and organic acids that direct inhibit the pathogens present in microbiota in the intestinal mucosa (Rattray and O’Connel 2011). These beneficial components have also shown to present bacteriostatic effect on Gram-negative organisms, but a better bactericidal effect against Gram-positive organisms (Czamanski et al. 2004). The main pathogens, Enterobacteria and Clostridium can be affected by kefir consumption. Activity against Yersinia entero- colitica, Escherichia coli, Listeria innocua, Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus and Salmonella Enteritidis, were also related (Czamanski et al. 2004). In Russia, kefir is used as coadjuvant in treatment of peptic ulcers in the stomach and duodenum of human patients (Leite et al. 2013).
The consumption of kefir beverage has a positive effect on the control of cholesterol level and fraction rate. With regular consumption of kefir, the total cholesterol, low density lipoproteins (LDL) and triglycerides decreases and high density lipoprotein (HDL) and protein C reactive (CRP) increase (Punaro et al. 2014; Ostadrahimi et al. 2015).
Possible mechanisms proposed for the hypocholesterolemic activity may involve the inhibition of the exogenous cholesterol absorption in the small intestine, by the binding and incorporation of cholesterol to bacterial cells and cholesterol uptake by probiotic bacteria used to their own metabolism (Ostadrahimi et al. 2015). In addition, the deconjugation of cholesterol to the bile salts, suppress the bile acid reabsorption (Leite et al. 2013; Ostadrahimi et al. 2015).
About 70% of the Brazilian population has some level of lactose intolerance due to the Asian and African genetic heritage of the population. Lactose is the main carbohydrate disaccharide present in milk and the lactose intolerance is a disorder associated with the inability to digest lactose (Ahmed et al. 2013; Leite et al. 2013).
The p-galactosidase is an enzyme that hydrolyses the lactose and is present in an active form in kefir grains after the fermentation process. This enzyme present in kefir beverage has the property to promote a decrease in the hydrogen expired and flatulence level in lactose intolerant subjects (Ahmed et al. 2013; Leite et al. 2013).