Consumption of fermented and nonfermented dairy products: effects on cholesterol concentrations and metabolism

Abstract

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.

Effects of ginger root (Zingiber officinale) on egg yolk cholesterol, antioxidant status and performance of laying hens

“…The cholic and deoxycholic bile acids are produced from cholesterol by hepatocytes and are conjugated with glycine and taurine, respectively. These acids enter the small intestine, where they are absorbed and directed to liver, and a decrease in bile acid recycling would ultimately result in a lowering of serum cholesterol concentration because cholesterol is used for bile acid synthesis (St-Onge et al 2000). However, we did not measure the amount of bile acid synthesis to support this speculation.…”

Probiotic capsules do not lower plasma lipids in young women and men

“…In vitro simulation has suggested that whereas some species of L. and B. lose viability during gastric transit, ingestion with milk proteins improves their tolerance to the pH of upper GI system (Charteris, 1998). In addition to its potential effect on bacterial viability, milk has been hypothesized to contain components such as 3-hydroxymethyl glutarate and orotic acid that may independently lower cholesterol (Mann, 1977;St-Onge et al, 2000). Although changes in intestinal microflora were not assessed in the present study, fecal bacteria and enzymes were altered by provision of L. acidophilus DDS-1 and B. longum UABL-14 in a concurrently conducted study in postmenopausal women (Greany et al, 2004) suggesting that the bacteria did remain viable and reach the intestines.…”

Nonalcoholic Fatty Liver Disease, the Gut Microbiome, and Diet

“…in n-3 PUFA-depleted mice (58). Moreover, it has been shown that an increase in lactic acid bacteria, such as Bifidobacterium spp., is related to a reduction in cholesterol absorption (154) and an increase in bile acid deconjugation, which leads to more excretion of bile acids and elimination of hepatic cholesterol (155).…”