Type and amount of individual dietary fibers on: Serum lipid profiles, serum glucose concentration and energy intake in rats

The role of soluble and insoluble dietary fibers on the regulation of: the serum lipid profile, serum glucose concentration and energy intake is currently uncertain. To help resolve this uncertainty, 90 Sprague-Dawley rats were fed a modified AIN-76 semipurified diet to compare the long-term effects of two dosage levels of four individual dietary fibers on serum lipid and glucose levels and on energy consumption. The rats were divided into nine groups and had free access to a fiberfree diet supplemented with: no fiber or 5 and 10% levels of cellulose, lignin, pectin or guar gum for 24 wk. Body weights and energy intake were measured weekly and samples of serum, feces and cecal chyme were analyzed at the conclusion of the experiment. Consumption of the non-fermentable fibers, cellulose and lignin had no significant effect on the serum cholesterol profile or glucose concentration. Consumption of high levels of the fermentable fibers pectin and guar gum reduced: serum cholesterol and glucose concentrations, pH of and diffusivity within the cecal chyme, and energy intake. Although 10% lignin consumption significantly increased total bile acid excretion, lignin did not reduce serum cholesterol. Regression analyses of the data revealed that diffisivity within the cecal chyme and energy consumption (but not bile acid excretion) were significantly associated with reduction in serum cholesterol and serum glucose concentrations.