Abstract
Background: Epidemiological and experimental studies have indicated that an increase of plant proteins in diets, as well as a substitution of red meat proteins or processed meat proteins with plant proteins, was closely associated with the reduction of cardio-cerebrovascular disease (CVD)-related mortality. One of the most important ways of plant proteins to reduce the incidence rate of CVD is to lowering cholesterol concentration in serum and liver. Mounting evidences have attributed this effect of plant proteins to their regulation of gut microbiota. However, it remains to be elucidated whether gut microbiota play decisive roles in modulating host cholesterol by dietary protein from diverse sources of plant or meat. This study attempted to clarify the relevant mechanisms by comparing the difference in cholesterol metabolism modulation between pea and pork proteins intake of hypercholesterolemia hamster, as well as its relationships with gut microbiome and metabolic pathway.Results: We have verified that there are significant differences in the regulations of serum and liver cholesterol levels among different proteins intake from plants (rice, oat, soybean, pea) or meat (chicken, pork, beef), and the corresponded differences in gut microbiota were also observed. The decisive roles of gut microbiota in regulating host cholesterol were illustrated by the findings that the differences in serum cholesterol level between pea protein and pork protein disappeared in the hamsters treated with antibiotics. The experimental results of cross-over intervention of pea and pork protein showed that the serum cholesterol level was reversed with dietary exchange. Most interestingly, the corresponded changes in abundance of dominant bacteria suggested that the “beneficial” microbe Muribaculaceae were responsible for the inhibitory effect of pea protein on serum cholesterol level, while the opposite effect of pork protein was due to the “harmful” microbe Erysipelotrichaceae. Moreover, dietary pea protein supplement altered cecal metabolites including changes in arginine/histidine pathway, primary bile acid biosynthesis, short chain fatty acids or other lipid-like molecules, which involved in cholesterol metabolism.Conclusion: Dietary pea protein exerted cholesterol-lowering effects through modulating the growth of selected gut microbiota in hamsters. The substitution of pork protein with pea protein could reshape the gut microbiota, affect the contents of metabolites in caecum, and thus regulate cholesterol metabolism. These findings suggest specific bacteria and metabolites can be potential therapeutic targets of hypercholesterolemia by plant protein intervention.
Obesity Does Not Interfere with the Cholesterol-Lowering Effect of Plant Stanol Ester Consumption (as Part of a Heart-Healthy Diet)