PSYLLIUM, NOT PECTIN OR GUAR GUM, ALTERS LIPOPROTEIN AND BILIARY BILE-ACID COMPOSITION AND FECAL STEROL EXCRETION IN THE HAMSTER

Different soluble dietary fibers known to alter cholesterol metabolism were fed to golden Syrian hamsters, and their specific impact on lipo proteins, biliary bile acid profile, and fecal sterol excretion was ev aluated. Semipurified diets containing 20% fat; 0.12% cholesterol; and 8% of psyllium (PSY); high (hePE) and low (lePE) esterified pectin; o r high (hvGG) and low (IvGG) viscous guar gum were fed for 5 wk. Compa red to central, PSY caused a significant reduction in plasma cholester ol (2.9 +/- 0.5 vs. 5.5 +/- 0.5 mmol/L), whereas hePE, lePE, hvGG, or IvGG had no apparent effect on plasma lipids. Hepatic total and esteri fied cholesterol were substantially decreased with PSY, pectin and gua r gum, whereby PSY produced the most pronounced effect. Distinctive ch anges existed in the bile acid profile related to the different fibers . In contrast to pectin and guar gum, PSY caused a significant increas e in the cholate:chenodeoxycholate and the glycine:taurine conjugation ratio. Pectin and guar gum did not alter daily fecal neutral sterol e xcretion while PSY caused a 90% increase due to a higher fecal output. Daily fecal bile acid excretion and total fecal bile acid concentrati on were significantly increased by PSY, whereas hePE, lePE, hvGG, and IvGG revealed no or only minor effects. Taken together, the disparate hypocholesterolemic effects of PSY, pectin, and guar gum on cholestero l and bile acid metabolism in the hamster are possibly related to diff erent physicochemical properties, e.g., viscosity and susceptibility t o fermentation, affecting the fiber-mediated action in the intestine.