Mechanism of Blood Cholesterol-Lowering Action of Parabiotics

Abstract

Parabiotics, which are inactivated or killed probiotic cells, have various beneficial effects on the human body, including the regulation of blood cholesterol levels, similar to live probiotics. Recently, heat treated dry powder of Bifidobacterium breve IDCC 4401, was found to lower the blood cholesterol level and approved by Korea Ministry of Food and Drug Safety as a health supplement that can be used for this purpose. In this article, the literature studying cholesterol-lowering mechanism of parabiotics were reviewed and the suggested mechanisms are summarized as follows. First, direct binding of parabiotics to dietary cholesterol and bile acids in the intestine, thereby inhibiting their absorption and promoting their excretion. Second, activating nuclear receptors (liver X receptor) of enterocytes which modulate the transport of cholesterol by suppressing the expression of an influx protein, Niemann-Pick C1-like 1 (NPC1L1) and promoting the expression of an efflux transporter, ATP-Binding Cassette (ABC). Third, reducing lipid synthesis through the suppression of the gene expressions of PPAR-γ, SREBP-1c, and FAS in the liver. The components that carry out the above actions are not known and thus, further studies are needed to identify them.