Chronic administration of the soluble, nonbacterial fraction of kefir attenuates lipid deposition in LDLr −/− mice

Kefir is obtained by the action of acidic bacteria and yeasts that exist in symbiotic association in kefir grains. Recently, this fermented milk drink has been recommended for the treatment of several clinical conditions, such as inflammatory, gastrointestinal, or cardiovascular-related diseases, or a combination of these diseases. However, its effects on atherosclerosis are not yet clear. The aim of this study was to prove that chronic treatment with a soluble, nonbacterial fraction of kefir could reduce the progression of atherosclerosis in low-density lipoprotein receptor–deficient (LDLr−/−) mice. LDLr−/− mice were divided into four groups as follows: The normal diet group received a normal diet without treatment. The high-fat diet (HD) group received a high-fat diet without treatment. The HD-milk group received a high-fat diet and was orally treated with 22 mL/kg of the vehicle. The HD-kefir group received a high-fat diet and was orally treated with soluble, nonbacterial fraction of kefir (22 mL/kg) for 4 wk. At the end of experiment, blood was collected to measure cholesterol and cytokines, and the aorta was collected to evaluate the lipid deposition by en face analysis. The soluble, nonbacterial fraction of kefir reduced lipid deposition (P < 0.05) independent of hypercholesterolemia. Moreover, kefir was capable of diminishing the circulating proinflammatory intereukin (IL)-6 level and the ratio of tumor necrosis factor-α to IL-10 (50% and 42%, P < 0.05, respectively) and augmenting the antiinflammatory IL-10 level by approximately 74% (P < 0.05). Chronic treatment with a soluble nonbacterial fraction of kefir was able to decrease the lipid deposition in LDLr−/− hypercholesteremic mice, at least in part through modifying the circulating cytokine profile. The beneficial effects of kefir provide new perspectives for its use as an adjuvant in the prevention of atherosclerosis.