Soluble fibers such as guar gum (GG) may exert cholesterol-lowering effects. It is generally accepted that bile acid (BA) reabsorption in portal blood is reduced, thus limiting the capacity of BA to down-regulate liver cholesterol 7α-hydroxylase, the rate-limiting enzyme of BA synthesis. In the present work, rats were adapted to fiber-free (FF) or 5% GG diets (supplemented or not with 0.25% cholesterol), to investigate various aspects of enterohepatic BA cycling. GG in the diet at a level of 5% elicited a significant lowering of plasma cholesterol during the absorptive period, in cholesterol-free (−13%) or 0.25% cholesterol (−20%) diet conditions. In rats adapted to the GG diets, the small intestinal and cecal BA pools and the ileal vein-artery difference for BA were markedly enhanced; reabsorption in the cecal vein was also enhanced in these rats. [14C]Taurocholate absorption, determined in perfused ileal segments, was not significantly different in rats adapted to the FF or GG diet, suggesting that a greater flux of BA in the ileum might support a greater ileal BA reabsorption in rats adapted to the GG diet. In contrast, capacities for [14C]cholate absorption from the cecum at pH 6.5 were higher in rats adapted to the GG diet than to the FF diet. Acidification of the bulk medium in isolated cecum (from pH 7.1 down to pH 6.5 or 5.8) or addition of 100 mM volatile fatty acids was also found to stimulate cecal [14C]cholate absorption. These factors could contribute to accelerated cecal BA absorption in rats fed the GG diet. The effects of GG on steroid fecal excretion thus appear to accompany a greater intestinal BA absorption and portal flux to the liver. These results suggest that some mechanisms invoked to explain cholesterol-lowering effect of fibers should be reconsidered.
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analysis of variance
active sodium-dependent bile acid transporter
short-chain fatty acid
steroid=sterols+bile acids (in digestive or fecal samples)
Glore, S.R., Van Treeck, D., Knehaus, A.W., and Guild, M. (1994) Soluble Fiber and Serum Lipids: A Literature Review, J. Am. Diet. Assoc. 94, 425–436.
Fernandez, M.L., Sun, D.M., Tosca, M., and McNamara, D.J. (1995) Guar Gum Effects on Plasma Low-Density Lipoprotein and Hepatic Cholesterol Metabolism in Guinea Pigs Fed Low-and High-Cholesterol Diets: A Dose-Dependent Study, Am. J. Clin. Nutr. 61, 127–134.
Truswell, A.S. (1995) Dietary Fibre and Blood Lipids, Curr. Opin. Lipidol. 6, 14–19.
Moundras, C., Behr, S.R., Rémésy, C., and Demigné, C. (1997) Fecal Losses of Sterols and Bile Acids Induced by Feeding Rats Guar Gum Are Due to a Greater Pool Size and Liver Bile Acids Secretion, J. Nutr. 127, 1068–1076.
Trautwein, E.A., Kunath-Rau, A., and Erbersdobler, E. (1998) Effect of Different Varieties of Pectin and Guar Gum on Plasma, Hepatic and Biliary Lipids and Cholesterol Gallstone Formation in Hamsters Fed on High-Cholesterol Diets, Br. J. Nutr. 79, 463–471.
Stedronsky, E.R. (1994) Interaction of Bile Acids and Cholesterol with Non-systemic Agents Having Hypocholesterolemic Properties, Biochim. Biophys. Acta 1210, 255–287.
Gee, J.M., Blackburn, N.A., and Johnson, I.T. (1983) The Influence of Guar Gum on Intestinal Cholesterol Transport in the Rat, Br. J. Nutr. 50, 215–224.
Phillips, D.R. (1986) The Effect of Guar Gum in Solution on Diffusion of Cholesterol Mixed Micelles, J. Sci. Food Agric. 37, 548.
Hofmann, A.F. (1994) in Physiology of the Gastrointestinal Tract (Johnson, L.R., ed.) 3rd edn., pp. 1845–1865, Raven Press, New York.
Schneider, B.L., Dawson, P.A., Christie, D-M., Hardikar, W., Wong, M.H., and Suchy, F.J. (1995) Cloning and Molecular Characterization of the Ontogeny of Rat Ileal Sodium-Dependent Bile Acid Transporter, J. Clin. Invest. 95, 745–754.
Craddock, A.L., Love, M.W., Daniel, R.W., Kirby, L.C., Walters, H.C., Wong, M.H., and Dawson, P.A. (1998) Expression and Transport Properties of the Human Ileal and Renal Sodium-Dependent Bile Acid Transporter, Am. J. Physiol. 274, G157-G169.
Riottot, M., and Sacquet, E. (1985) Increase in the Ileal Absorption Rate of Sodium Taurocholate in Germ-free or Conventional Rats Given an Amylomaize-Starch Diet, Br. J. Nutr. 53, 307–310.
Lillienau, J., Crombie, D.L., Munoz, J., Longmire-Cook, S.J., Hagey, L.R., and Hofmann, A.F. (1993) Negative Feedback Regulation of the Ileal Bile Transport System in Rodents, Gastroenterology 104, 38–46.
Stravitz, R.T., Sanya, A.J., Pandak, W.M., Vlahcevic, Z.R., Beets, J.W., and Dawson, P.A. (1997) Induction of Sodium-Dependent Bile Acid Transporter Messenger RNA, Protein, and Activity in Rat Ileum by Cholic Acid, Gastroenterology 113, 1599–1608.
Fukushima, K., Ichimiya, H., Higashijima, H., Yamashita, H., Kuroki, S., Chijiwa, K., and Tanaka, M. (1995) Regulation of Bile Acid Synthesis in the Rat: Relationship Between Hepatic Cholesterol 7α-Hydroxylase Activity and Portal Bile Acids, J. Lipid Res. 36, 315–321.
Demigné, C., Levrat, M.-A., Behr, S., Moundras, C., and Rémésy, C. (1998) Cholesterol-Lowering Action of Guar Gum in the Rat: Changes in Bile Acids and Sterols Excretion and in Enterohepatic Cycling of Bile Acids, Nutr. Res. 18, 1215–1225.
Danielsson, H., Einarsson, K., and Johansson, G. (1967) Effect of Biliary Drainage on Individual Reactions in the Conversion of Cholesterol to Taurocholic Acid, Eur. J. Biochem. 2, 44–49.
Princen, H.M.G., Post, S.M., and Twisk, J. (1997) Regulation of Bile Acid Biosynthesis, Current Pharmaceut. Design 3, 59–84.
Todd, P.A., Benfield, P., and Goa, K.L. (1990) Guar Gum. A Review of Its Pharmacological Properties, and Use as a Dietary Adjunct in Hypercholesterolemia, Drugs 39, 917–928.
Anderson, J.W., Jones, A.E., and Riddell-Mason, S. (1994) Ten Different Dietary Fibers Have Significant Different Effects on Serum and Liver Lipids on Cholesterol-Fed Rats, J. Nutr. 124, 78–83.
Vahouny, G.V., Tombes, R., Cassidy, M.M., Kritchevsky, D., and Gallo, L.L. (1980) Dietary Fibers: V. Binding of Bile Salts, Phospholipids and Cholesterol from Mixed Micelles by Bile Acid Sequestrants and Dietary Fibers, Lipids 15, 1012–1018.
Favier, M.-L., Bost, P.-E., Guittard, C., Demigné, C., and Rémésy, C. (1997) The Cholesterol-Lowering Effect of Guar Gum Is Not the Result of a Simple Diversion of Bile Acids Toward Fecal Excretion, Lipids 32, 953–959.
Ikegami, S., Tsuchihashi, F., Harada, H., Tsuchihashi, N., Nishide, E., and Innani, S. (1990) Effect of Viscous Indigestible Polysaccharide on Pancreatic-Biliary Secretion and Digestive Organs in Rats, J. Nutr. 120, 353–360.
Ide, T., Moruichi, H., and Nihimoto, K. (1991) Hypolipidemic Effects of Guar Gum and Its Enzyme Hydrolysate in Rats Fed Highly Saturated Fat Diets, Ann. Nutr. Metab. 35, 34–44.
Ide, T., and Horii, M. (1987) A Simple Method for Extraction and Determination of Non-conjugated and Conjugated Luminal Bile Acids in Rats, Agric. Biol. Chem. 51, 3155–3157.
Lewis, M.C., and Root, C. (1990) In vivo Transport Kinetics and distribution of Taurocholate by Rat Ileum and Jejunum, Am. J. Physiol. 259, G233-G238.
Juste, C., Legrand-Defretin, V., Corring, T., and Rerat, A. (1988) Intestinal Absorption of Bile Acids in the Pig. Role of Distal Bowel, Dig. Dis. Sci. 33, 67–73.
Nowicki, M.J., Shneider, B.L., Paul, J.M., and Heubi, J.E. (1997) Glucocorticoids Upregulate Taurocholate Transport by Ileal Brush-border Membrane, Am. J. Physiol. 273, G197-G203.
Arrese, M., Trauner, M., Sacchiero, R.J., Crossman, M.W., and Schneider, B.L. (1998) Neither Intestinal Sequestration of Bile Acids Nor Common Bile Duct Ligation Modulate the Expression and Function of the Rat Ileal Bile Acid Transporter, Hepatology 28, 1081–1087.
Stark, A., Nyska, A., and Madar, Z. (1996) Metabolic and Morphometric Changes in Small and Large Intestine in Rats Fed High-Fiber Diets, Toxicol. Pathol. 24, 166–171.
Brown, N.J., Worlding, J., Rumsey, R.D.E., and Read, N.W. (1988) The Effect of Guar Gum on the Distribution of a Radiolabelled Meal in the Gastrointestinal Tract of the Rat, Br. J. Nutr. 59, 223–231.
Cherbut, C., Albina, E., Champ, M., Doublier, J.L., and Lecannu, G. (1990) Action of Guar Gums on the Viscosity of Digestive Contents and on the Gastrointestinal Motor Function in Pigs, Digestion 46, 205–213.
Björkhem, I., Eggerston, G., and Andersson, U. (1991) On the Mechanism of Stimulation of Cholesterol 7α-Hydroxylase by Dietary Cholesterol, Biochim. Biophys. Acta 1085, 329–335.
Ide, T., Horii, M., Yamamoto, T., and Kawashima, K. (1990) Contrasting Effects of Water-Soluble and Water-Insoluble Dietary Fibers on Bile Acid Conjugation and Taurine Metabolism in the Rat, Lipids 25, 335–340.
Aldini, R., Montagnani, M., Roda, A., Hrelia, S., Biagi, P.L., and Roda, E. (1996) Intestinal Absorption of Bile Acids in the Rabbit: Different Transport Rates in Jejunum and Ileum, Gastroenterology 110, 459–468.
Dumaswala, R., Berkowitz, D., Setchell, K.D., and Heubi, J.E. (1994) Effects of Fasting on the Enterohepatic Circulation of Bile Acids in Rats, Am. J. Physiol. 267, G836-G842.
Walker, S., Stiehl, A., Raedsch, R., Kloters, P., and Kommerell, B. (1985) Absorption of Urso- and Chenodeoxycholic Acid and Their Taurine and Glycine Conjugates in Rat Jejunum, Ileum, and Colon, Digestion 32, 47–52
Rémésy, C., Levrat, M.-A., Gamet, L., and Demigné, C. (1993) Cecal Fermentations in Rats Fed Oligosaccharides (inulin) Are Modulated by Dietary Calcium Level, Am. J. Physiol. 264, G855-G862.
Gelissen, I., and Eastwood, M.A. (1995) Taurocholic Adsorption During Non-starch Polysaccharide Fermentation: An in vitro Study, Br. J. Nutr. 74, 221–228.
Cronholm, T., and Sjövall, J. (1967) Bile Acids in Portal Blood of Rats Fed Different Diets and Cholestyramine, Eur. J. Biochem. 2, 375–383.
Pandak, W.M., Heuman, D.M., Hylemon, P.B., Chiang, J.Y.L., and Vlahcevic, Z.R. (1995) Hailure of Intravenous Infusion of Taurocholate to Down-regulate Cholesterol 7α-Hydroxylase in Rats with Biliary Fistula, Gastroenterology 108, 533–544.
Stange, E.F., Scheibner, J., and Ditschuneit, H. (1989) Role of Primary and Secondary Bile Acids as Feedback Inhibitors of Bile Acid Synthesis in the Rat in vivo, J. Clin. Invest. 84, 173–180.
Stravitz, R.T., Vlahcevic, Z.R., Gurley, E.C., and Hylemon, P.B. (1995) Repression of Cholesterol 7α-Hydroxylase Transcription by Bile Acids Is Mediated Through Protein Kinase C in Primary Cultures of Rat Hepatocytes, J. Lipid Res. 36, 1359–1369.
Stroup, D., Crestani, M., Chiang, J.Y.L. (1997) Identification of a Bile Acids Response Element in the Cholesterol 7α-Hydroxylase Gene CYP7A, Am. J. Physiol. 273, G508-G517.
Jenkins, D.J.A., Leeds, A.R., Gassull, M.A., Cochet, B., and Alberti, K.G.M.M. (1977) Decrease in Postprandial Insulin and Glucose Concentrations by Guar and Pectin, Ann. Intern. Med. 86, 20–23.
Morand, C., Levrat, M., Besson, C., Demigné, C., and Rémésy C. (1994) Effect of a Diet Rich in Resistant Starch on Hepatic Lipid Metabolism in the Rat, J. Nutr. Biochem. 5, 138–144.
Vlahcevic, Z.R., Stravitz, R.T., Heuman, D.M., Hylemon, P.B., and Pandak, W.M. (1997) Quantitative Estimations of the Contribution of Different Bile Acid Pathways to the Total Bile Acid Synthesis in the Rat, Gastroenterology 113, 1949–1957.
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Moriceau, S., Besson, C., Levrat, MA. et al. Cholesterol-lowering effects of guar gum: Changes in bile acid pools and intestinal reabsorption. Lipids 35, 437–444 (2000). https://doi.org/10.1007/s11745-000-542-x
- Bile Acid
- Resistant Starch
- Unstirred Layer
- Bile Acid Pool