Fermentable carbohydrates exert a more potent cholesterol-lowering effect than cholestyramine.
The purpose of this work was to assess the respective role of bile acid excretion and of the end-products of cecal fermentations in the cholesterol-lowering effect of complex carbohydrates. The effects of two different fermentable carbohydrates (guar gum, beta-cyclodextrin), and sequestrant resin (cholestyramine) have been investigated in male Wistar rats. Guar gum and beta-cyclodextrin are broken down in the large bowel, with fermentation rich in propionic acid (37% against 26% for control), whereas cholestyramine did not enhance cecal fermentation. beta-Cyclodextrin and guar gum were less potent than cholestyramine to enhance bile acids and sterol excretion. Nevertheless, fermentable carbohydrates exerted a more potent cholesterol-lowering effect than cholestyramine. beta-Cyclodextrin also depressed triacylglycerol-rich lipoprotein (TGRLP). Fermentable carbohydrates lowered cholesterol of LDL and HDL1 fractions. The induction of hepatic HMG-CoA reductase was practically proportional to rate of fecal steroid excretion. Moreover, with beta-cyclodextrin, hepatic HMG-CoA reductase induction was concomitant to a decrease in fatty acid synthase (FAS) activity. Thus, the cholesterol-lowering effect of fermentable carbohydrates could be related to a depressed lipogenesis, as well as to an accelerated removal of HDL1, in relation to an elevated hepatic demand of cholesterol. In conclusion, fermentable carbohydrates could favour cholesterol elimination and have a general lipid-lowering effect by exerting more complex physiological effects than cholestyramine.
Favier
M L
ML
Laboratoire des Maladies Métaboliques, I.N.R.A. de Clermont-Ferrand/Theix, Ceyrat, France.
Moundras
C
C
Demigné
C
C
Rémésy
C
C
D000818:Animals; D000924:Anticholesteremic Agents / Q000494:pharmacology*; D001647:Bile Acids and Salts / Q000378:metabolism; D001835:Body Weight; D002432:Cecum / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism*; D002792:Cholestyramine Resin / Q000494:pharmacology*; D003505:Cyclodextrins / Q000378:metabolism; D004040:Dietary Carbohydrates / Q000378:metabolism*; D005285:Fermentation; D005685:Galactans / Q000378:metabolism; D008297:Male; D008351:Mannans / Q000378:metabolism; D053149:Plant Gums; D051381:Rats; D017208:Rats, Wistar; D014280:Triglycerides / Q000378:metabolism; D047392:beta-Cyclodextrins
D000924:Anticholesteremic Agents; D001647:Bile Acids and Salts; D003505:Cyclodextrins; D004040:Dietary Carbohydrates; D005685:Galactans; D008351:Mannans; D053149:Plant Gums; D014280:Triglycerides; D047392:beta-Cyclodextrins; D002792:Cholestyramine Resin; D002784:Cholesterol; C007894:guar gum; C031215:betadex