The Protective Anti-oxidant Effects of Kefir on SFME Neural Stem Cells

Abstract

Kefir is a traditional fermented food in the Caucasus, an area famous for longevity of its inhabitants. Kefir is made from milk fermented with a complex and specific microbial mixture including lactobacilli, yeast, and acetobacteria. Resent studies have shown the various activities of kefir on suppression of tumor growth, activation of the immune system, and inhibition of oxidative damage. Oxidative stress may be a cause of neural cell death in aging-associated diseases of the nervous system such as Alzheimer’s disease, Parkinson’s disease, and ischemia from stroke. For this reason, we examined the protective effect of kefir on oxidative stress in cultured cells derived from mouse brain. The cells were acutely sensitive to oxidative stress induced by the absence of the antioxidants such as vitamin E and seleniun. Kefir markedly prevented this oxidative-induced cell death. The anti-oxidative activity of kefir is of molecular weight less than 3,500 and stable on boiling or incubation at pH 2 to pH 12, but is lost upon extreme heating to ash. The major portion of the activity was hydrophilic contained both positively charged and negatively charged components. Also, the activity was found in preparations fermented from rice or soy, which suggest that the activity is a product of the microbiol fermentation. The low molecular weight and extreme stability of the antioxidant activity in kefir suggest that the activity may be easily absorbed through the digestive system and distributed throughout the body including the brain. The antioxidant activity of kefir may be responsible for a significant portion of the health-promoting effects attributed to this material.