Zhang X, Beynen A C
Department of Nutrition and Food Hygiene, Shanxi Medical College, Taiyuan, People's Republic of China.
Br J Nutr. 1993 Jul;70(1):139-46. doi: 10.1079/bjn19930111.
The effect of dietary whey protein v. casein on plasma and liver cholesterol concentrations was investigated in female, weanling rats. Balanced, purified diets containing either whey protein or casein, or the amino acid mixtures simulating these proteins, were used. The high-cholesterol diets (10 g cholesterol/kg feed) had either 150 or 300 g protein or amino acids/kg feed. The diets were fed for 3 weeks. At the low dietary protein level, whey protein v. casein did not affect plasma total cholesterol, but lowered the concentration of liver cholesterol. At the high dietary protein level, whey protein significantly lowered plasma and liver cholesterol and also plasma triacylglycerols. The hypocholesterolaemic effect of whey protein was associated with a decrease in very-low-density-lipoprotein cholesterol. At the high dietary protein concentration, whey protein reduced the faecal excretion of bile acids when compared with casein. The effects of intact whey protein v. casein were not reproduced by the amino acid mixtures simulating these proteins. It is suggested tentatively that the cholesterol-lowering effect of whey protein in rats is caused by inhibition of hepatic cholesterol synthesis.
在断奶雌性大鼠中研究了膳食乳清蛋白与酪蛋白对血浆和肝脏胆固醇浓度的影响。使用了含有乳清蛋白或酪蛋白，或模拟这些蛋白质的氨基酸混合物的均衡纯化日粮。高胆固醇日粮（每千克饲料含10克胆固醇）每千克饲料含有150或300克蛋白质或氨基酸。日粮喂养3周。在低膳食蛋白质水平时，乳清蛋白与酪蛋白相比对血浆总胆固醇无影响，但降低了肝脏胆固醇浓度。在高膳食蛋白质水平时，乳清蛋白显著降低了血浆和肝脏胆固醇以及血浆甘油三酯。乳清蛋白的降胆固醇作用与极低密度脂蛋白胆固醇的降低有关。在高膳食蛋白质浓度时，与酪蛋白相比，乳清蛋白减少了胆汁酸的粪便排泄。模拟这些蛋白质的氨基酸混合物未重现完整乳清蛋白与酪蛋白的作用效果。初步认为，乳清蛋白在大鼠中的降胆固醇作用是由抑制肝脏胆固醇合成引起的。
