Dietary fiber and lymphatic absorption of cholesterol in the rat.

The indirect effects of short-term (3-day) feeding of several types of dietary fiber and nonnutritive materials on the subsequent absorption of cholesterol has been investigated in thoracic duct cannulated rats. Absorption was studied at timed intervals over 24 hr after duodenal introduction of a tracer dose of cholesterol at least 20 hr after the last feeding. In animals fed for 3 days with diets containing cholestryamine, bran, or cellulose, cholesterol absorption was significantly less than in control animals maintained on rat chow. Rats fed for 3 days with an alfalfa-containing diet showed large variations in cholesterol absorption that were not significantly different from controls. However, after 5 weeks, rats on the alfalfa diet showed a marked reduction in lymphatic absorption of the tracer sterol. These indirect effects of cholestryamine and fibers on cholesterol absorption were not attributable to a common mechanism; i.e., differences in transit times that were not significant, or dirrect binding of bile acids and cholesterol by the test materials.