St-Onge M P, Farnworth E R, Jones P J
School of Dietetics and Human Nutrition, McGill University, Ste-Anne-de-Bellevue, Canada.
Am J Clin Nutr. 2000 Mar;71(3):674-81. doi: 10.1093/ajcn/71.3.674.
The objective of this article was to review existing literature concerning the effects and mechanisms of action of fermented dairy products on serum cholesterol concentrations. Although not without exception, existing evidence from animal and human studies suggests a moderate cholesterol-lowering action of fermented dairy products. Mechanistically, fermented milk has been shown to cause an increase in human gut bacterial content. These bacteria, once resident in the large intestine, are believed to ferment food-derived indigestible carbohydrates. Such fermentation causes increased production of short-chain fatty acids, which decreases circulatory cholesterol concentrations either by inhibiting hepatic cholesterol synthesis or by redistributing cholesterol from plasma to the liver. Furthermore, increased bacterial activity in the large intestine results in enhanced bile acid deconjugation. Deconjugated bile acids are not well absorbed by the gut mucosa and are excreted. Consequently, cholesterol, being a precursor of bile acids, is utilized to a greater extent for de novo bile acid synthesis. These actions combined are proposed as contributing mechanisms to the association of fermented milk consumption with decreased circulating cholesterol concentrations.
本文的目的是综述关于发酵乳制品对血清胆固醇浓度的影响及其作用机制的现有文献。尽管并非毫无例外，但来自动物和人体研究的现有证据表明，发酵乳制品具有适度的降低胆固醇作用。从机制上讲，发酵乳已被证明会使人体肠道细菌含量增加。这些细菌一旦在大肠中定植，就被认为会发酵食物中难以消化的碳水化合物。这种发酵会导致短链脂肪酸产量增加，短链脂肪酸通过抑制肝脏胆固醇合成或通过将胆固醇从血浆重新分配到肝脏来降低循环胆固醇浓度。此外，大肠中细菌活性的增加会导致胆汁酸去结合作用增强。去结合的胆汁酸不易被肠道黏膜吸收并被排出。因此，胆固醇作为胆汁酸的前体，会更多地被用于从头合成胆汁酸。这些综合作用被认为是发酵乳消费与循环胆固醇浓度降低之间关联的作用机制。
