Dietary soluble fiber lowers plasma LDL cholesterol concentrations by altering lipoprotein metabolism in female guinea pigs

• Published in: The Journal of nutrition Vol. 128; no. 9; pp. 1434 - 1441
• Main Authors: HONG SHEN, LIN HE, PRICE, R. L, FERNANDEZ, M. L
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Nutritional Sciences 01.09.1998; American Institute of Nutrition
• Subjects: Animals; Apolipoproteins B - analysis; Biological and medical sciences; Cholesterol; Cholesterol, HDL - analysis; Cholesterol, LDL - analysis; Cholesterol, LDL - blood; Diet; Dietary fiber; Dietary Fiber - pharmacology; Feeding. Feeding behavior; Female; Fundamental and applied biological sciences. Psychology; Galactans - pharmacology; Guinea Pigs; Hogs; Lipoproteins - blood; Lipoproteins - metabolism; Lipoproteins, VLDL - analysis; Male; Mannans - pharmacology; Microsomes, Liver - metabolism; Pectins - pharmacology; Plant Gums; Proteins; Psyllium - pharmacology; Sex Factors; Triglycerides - analysis; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Rodentia; Sex; Lipids; Pectin; Lipoprotein; Metabolism; Cholesterol; Feeding; Blood plasma; Vertebrata; Mammalia; Guinea pig; Diet; Guar gum; Dietary fiber
• ISSN: 0022-3166; 1541-6100
• DOI: 10.1093/jn/128.9.1434

This experiment was designed to evaluate the effects of pectin (PE), guar gum (GG) and psyllium (PSY) intake on VLDL and LDL metabolism in female guinea pigs fed high dietary cholesterol. Guinea pigs were fed a 15 g/100 g fat diet containing 0.25 g/100 g cholesterol with 12.5 g/100 g PE, 12.5 g/100 g GG, 7.5 g/100 g PSY or 12.5 g/100 g cellulose (control diet) for 4 wk. Plasma cholesterol concentrations were 29, 43 and 39% lower in guinea pigs fed PE, GG or PSY, respectively, compared with the control group (P < 0.0001). Plasma apolipoprotein (apo) B concentrations were 16-22% lower in the groups fed soluble fiber compared with the control group (P < 0.01). In contrast, hepatic cholesterol and triglyceride concentrations were not different among the PE, GG, PSY and control groups. No differences in triacylglycerol (TAG) or apo B secretion rates, measured by blocking VLDL catabolism by triton (WR 1339) injection, were observed, whereas plasma LDL apo B fractional catabolic rates (FCR), determined by injection of radiolabeled LDL, were higher in guinea pigs fed GG or PSY than in those from the control group. All sources of dietary soluble fiber reduced LDL apo B flux (P < 0.05). These results suggest that the mechanisms of plasma LDL cholesterol lowering by dietary soluble fiber are distinctive for each fiber source and result in specific alterations in lipoprotein metabolism in female guinea pigs. Differences between male and female guinea pigs in response to these diets are discussed.