Effect of Cultured Milk on Serum Cholesterol Concentrations in Rats which Fed High-cholesterol Diets

Abstract

Serum cholesterol concentrations of rats fed high-cholesterol diets containing skim milk or cultured milks were estimated periodically during 12 days. Several kinds of cultured milks could inhibit the increasing of serum cholesterol concentrations in rats throughout the experimental period compared with skim milk. It was found that this inhibiting ability depended mainly on the specificities of strains, not on the specificities of species. A part of inhibiting mechanism against the increasing serum cholesterol concentrations was analysed using L. acidophilus SBT 2056 (LA 2056) which was selected as most effective one among all strains examined. Feeding the LA 2056 cultured milk resulted in the significant increase of sterol concentrations in bile and feces and also the activity of hepatic cholesterol 7α hydroxylase. The LA 2056 cells had a inhibitory effect against cholesterol micelle absorption from intestines. On the other hand, there was no apparent stimulation effect in the whey fraction of LA 2056 cultured milk on the production of bile acids in primaly cultured rat hepatocytes. From these results, it was supposed that the inhibition effect of LA 2056 cultured milk against increasing of serum cholesterol concentrations in rats was caused partly by the bacterial cells.