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Effectiveness of resistant starch, compared to guar gum, in depressing plasma cholesterol and enhancing fecal steroid excretion
Author(s) -
Levrat MarieAnne,
Moundras Corinne,
Younes Hassan,
Morand Christine,
Demigné Christian,
Rémésy Christian
Publication year - 1996
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02522464
Subject(s) - cholesterol , guar gum , chemistry , triglyceride , polysaccharide , bile acid , cecum , excretion , medicine , resistant starch , food science , short chain fatty acid , endocrinology , starch , biochemistry , biology , butyrate , fermentation
Abstract Amylase‐resistant starch (RS) represents a substrate that can be administered in substantial amounts in the diet, in contrast to gel‐forming polysaccharides, such as guar gum (GG). The aim of this work was thus to compare the effects of GG and RS on cholesterol metabolism in rats adapted to 0.4% cholesterol diets, using dietary GG or RS levels (8 or 20%, respectively) that led to a similar development of fermentations, as assessed by the degree of enlargement of the cecum. The RS diet elicited a marked rise in the cecal pool of short‐chain fatty acids, especially acetic and butyric acid, whereas the GG diet favored high‐propionic acid fermentations. Both polysaccharides markedly altered the cholesterol excretion, from 50% of ingested cholesterol in controls, up to about 70% in rats adapted to the RS or GG diets. With these diets, the fecal excretion of bile acids was enhanced (67 and 144% with the RS and GG diets, respectively). RS and GG diets were effective in lowering plasma cholesterol (about −40%) and triglycerides (−36%). There was practically no effect of the diets on cholesterol in d>1.040 lipoproteins (high density lipoproteins), whereas RS (and to a larger extent, GG) were very effective to depress cholesterol in d<1.040 lipoproteins (especially in triglyceride‐rich lipoproteins). Fermentable polysaccharides counteracted the accumulation of cholesterol in the liver, especially cholesterol esters. In parallel, liver acyl CoA:cholesterol acyltransferase was depressed in rats fed the RS or GG diets, whereas only the GG diet counteracted the downregulation of 3‐hydroxy‐3‐methylglutaryl‐CoA by cholesterol. These data suggest that RS may be practically as effective as a gel‐forming gum, such as GG, on steroid excretion and on cholesterol metabolism.