Abstract
A soybean protein pepsin-hydrolyzate with bound phospholipids (SPHP-p) was prepared, and its effects (at 1-20% in the diet) on cholesterol levels were examined in rats. All the rats were fed a cholesterol-enriched diet for 10 days, followed by the experimental diets for a further 9 days. SPHP-p dose-dependently reduced the levels of serum and liver cholesterol which had already accumulated within the body. The cholesterol-reducing effect of SPHP-p was more marked in the cholesterol-enriched (0.5%) diet group than in the cholesterol-free diet group. Another preparation from soybean protein hydrolyzed with microbial protease instead of pepsin (SPHP-s) was also examined, and was shown to suppress cholesterol absorption by Caco-2 cells in vitro, and to reduce the levels of serum and liver cholesterol in rats fed a cholesterol-enriched diet with a potency comparable to that of SPHP-p. These results indicate that both SPHP-p and SPHP-s can not only suppress the accumulation of exogenous cholesterol, but also reduce cholesterol which has already accumulated within the body by suppressing the absorption of cholesterol in the intestinal tract.
