Cereal Chem 56:279 - 282.  |  VIEW ARTICLE
Steroid Metabolism, Transit Time, and Cecal Bacteria in Rats Fed Corn or Wheat Bran.

W. Y Lee, M. R. Bennink, and W. L. Chenoweth. Copyright 1979 by the American Association of Cereal Chemists, Inc. 

The effects of corn and wheat bran on serum cholesterol concentration, bile acid excretion, bile acid degradation, bowel function, and anaerobic cecal bacteria were studied in rats. Neither wheat bran nor corn bran lowered serum cholesterol, but serum cholesterol was increased in one experiment when wheat bran was added to the diet. When rats were switched from bran containing diets to be a bran free diet, the serum cholesteral concentration remained constant. In general, bran-fed rats excreted more bile acids than rats fed the low fiber control diet. Fat and fiber content of the diet affected both bile acid degradation and concentration in the large intestine of rats. Rats fed a 20% fat dies had increased bile acid degradation as the wheat bran content of the diet increased, but rats fed a 30% fat diet had extensive bile acid degradation regardless of wheat or corn bran content of the diet. Anaerobic bacterial concentrations in cecal contents were unaffected by dietary variables but bacterial type of metabolism was altered when bran was added to the 20% fat dies. Bran feeding decreased bile acid concentration in intestinal contents and decreased the time that indigestible material remained in the intestine. Since bile acids are suspected to be carcinogenic and cocarcinogenic, bran may play a role in decreasing the incidence of colonic cancer by diluting bile acids ain the large bowel.