Bifidobacteria Strain Behavior Toward Cholesterol: Coprecipitation with Bile Salts and Assimilation

Abstract

Resting cells and growing cells of bifidobacteria strains exhibited an ability to remove cholesterol in the presence of bile salts. In resting cell assays, the removed cholesterol was precipitated in the presence of cholic acid at pH values lower than 5.4. However, this precipitated cholesterol was redissolved when the pellets were washed with phosphate buffer, pH 7, and no cholesterol was found in the cells. It appears that this precipitation is a transient phenomenon. In the case of growing cells, the removed cholesterol was partially recovered when cells were washed with phosphate buffer, pH 7, while the remaining cholesterol was extracted from the cells. Cultured in the presence of radiolabeled free or esterified cholesterol, bifidobacteria strains were able to assimilate esterified cholesterol. It is concluded that the removal of cholesterol from the growth medium by bifidobacteria strains is due to both bacterial assimilation and precipitation of cholesterol.

Cholesterol Assimilation by Lactic Acid Bacteria and Bifidobacteria Isolated from the Human Gut

“…Considering the purported mechanisms behind this phenomenon, it is rational to assume that probiotic survival in the gut is a prerequisite. The results presented here partly confirm the data of Gilliland et al (7), Rašić et al (14), and Tahri et al (21) in that some strains of lactic acid bacteria and bifidobacteria are able to remove cholesterol from culture medium during anaerobic growth in the presence of bile acids. However, great variability was found between strains and even for the same strain during different experimental runs.…”

“…However, the role of fermented milk products as hypocholesterolemic agents in humans is still equivocal, as the clinical studies performed have given variable data and no firm conclusions can be drawn (6,23). From several in vitro studies a number of mechanisms have been proposed for the purported cholesterol-lowering action of probiotic bacteria (7,9,11,13,21,22,24). These include physiological actions of the end products of short-chain fatty acid fermentation (especially propionate), cholesterol assimilation by the bacteria, cholesterol binding to the bacterial cell wall, and enzymatic deconjugation of bile acids.…”

Dose–response study of probiotic bacteria Bifidobacterium animalis subsp lactis BB-12 and Lactobacillus paracasei subsp paracasei CRL-341 in healthy young adults

“…Results from several in vitro studies indicate that some strains of lactobacilli and bifidobacteria are able to reduce the concentration of cholesterol in a culture medium when grown under anaerobic conditions in the presence of bile acid (Tahri et al, 1996;Brashears et al, 1998;Pereira and Gibson, 2002). Likewise strains of B. animalis isolated from feces have shown to possess bile salt hydrolase activity (Tanaka et al, 1999).…”

Dietary Fiber and Availability of Nutrients: A Case Study on Yoghurt as a Food Model

“…Bacteria such as Lactobacillus and Bifidobacteria can exert a hypocholesterolemic effect by enhancing bile acid deconjugation [91,92]. Furthermore, Lactobacillus and Bifidobacteria remove cholesterol in vitro by assimilation and precipitation [93,94]. Fermentation products further affect lipid metabolism.…”