Effects of Consumption of Probiotics and Prebiotics on Serum Lipid Levels in Humans

Abstract

The objective of this article is to review existing studies concerning the effects of probiotics and prebiotics on serum cholesterol concentrations, with particular attention on the possible mechanisms of their action. Although not without exception, results from animal and human studies suggest a moderate cholesterol-lowering action of dairy products fermented with appropriate strain(s) of lactic acid bacteria and bifidobacteria. Mechanistically, probiotic bacteria ferment food-derived indigestible carbohydrates to produce short-chain fatty acids in the gut, which can then cause a decrease in the systemic levels of blood lipids by inhibiting hepatic cholesterol synthesis and/or redistributing cholesterol from plasma to the liver. Furthermore, some bacteria may interfere with cholesterol absorption from the gut by deconjugating bile salts and therefore affecting the metabolism of cholesterol, or by directly assimilating cholesterol. For prebiotic substances, the majority of studies have been done with the fructooligosaccharides inulin and oligofructose, and although convincing lipid-lowering effects have been observed in animals, high dose levels had to be used. Reports in humans are few in number. In studies conducted in normal-lipidemic subjects, two reported no effect of inulin or oligofructose on serum lipids, whereas two others reported a significant reduction in serum triglycerides (19 and 27%, respectively) with more modest changes in serum total and LDL cholesterol. At present, data suggest that in hyperlipidemic subjects, any effects that do occur result primarily in reductions in cholesterol, whereas in normal lipidemic subjects, effects on serum triglycerides are the dominant feature.

Lactobacillus acidophilus 74-2 and Bifidobacterium animalis subsp lactis DGCC 420 modulate unspecific cellular immune response in healthy adults

“…Probiotic bacteria are able to ferment dietary fibres to produce short-chain fatty acids in the gut that may result in a decrease in the systemic levels of blood lipids by inhibiting hepatic cholesterol synthesis (Pereira and Gibson, 2002). Although the yoghurt contained two probiotic cultures, no significant change in the concentration and ratio of shortchain fatty acids in faeces were observed.…”

The effects of prebiotic, probiotic and synbiotic diets containing Bacillus coagulans and inulin on serum lipid profile in the rat

“…In addition, the ability of particular strain of probiotic bacteria to attach permanently to the gut wall and hence continuous supply might be necessary to exert the effects. 21,22 The results of our previous study indicated that these bacteria are not able to colonize the intestine and are quickly eliminated in feces. 9 As such, daily consumption of probiotic products is necessary for any longterm effect on metabolism.…”

“…Cholesterol is used to synthesize new bile acids in a homeostatic response, resulting in lowering of serum cholesterol. [19][20][21] Ooi and Liong 20 in a review article attributed these controversial findings to various factors such as different strains of probiotics, administration dosage, analytical accuracy of lipid analyses, duration of treatment period, clinical characteristic of subjects, inadequate sample sizes, and lack of suitable controls or placebo groups. 2 Considering the mentioned reasons hypothesized by Ooi and Liong, 20 normolipidemic condition of used rat model in the current study may be a reason for failure of these probiotic bacteria in changing lipid profile.…”

Cholesterol lowering and inhibition of sterol absorption by Lactobacillus reuteri NCIMB 30242: a randomized controlled trial

“…26 It has been previously postulated that some probiotic lipid-lowering clinical trials lack appropriate strain selection, method of delivery or clinical design. 31 For the current study, a systematic approach was applied, including identifying a strain, L. reuteri NCIMB 30242, with the appropriate phenotypic characteristics including elevated natural BSH expression, ensuring the safety of the strain through phenotypic and genotypic characterization 32 and optimizing the production parameters of the strain.…”