Effects of dietary fiber from wheat, corn, and soy hull bran on excretion of fecal bile acids in humans

Effects of dietary fiber on bile acid excretion and fecal bile acid concentration have been studied for seven subjects fed 26 g of either soft white wheat bran, corn bran, soybean hulls, or hard red spring wheat bran. Results indicate that even in a controlled study using a metabolic word, individual subject variation has a major impact on fecal bile acid excretion. This observation has not been fully appreciated in previous human studies. No significant change in the composition of fecal bile acids could be associated with the decrease in serum lipid levels previously reported. A method for the isolation and quantitation of fecal bile acids is described which does not require purification by thin-layer chromatography. A preliminary study of lyophilized fecal samples stored at -10 to -30°C showed very little or no change in bile acid content. Samples stored at room temperatures for I I months showed a substantial reduction in bile acid content. Am. J. Clin. Nutr. 34: 1071-1076, 1981.