Protective role of wheat bran fiber: data from marker trials.

The effects of wheat bran fiber on surrogate endpoint biomarkers for colon cancer risk have been studied in rats and humans. In both species, there is little evidence that wheat bran fiber significantly modifies epithelial cell proliferation. In rat studies, however, dietary supplementation with wheat bran fiber has decreased mucosal formation of aberrant crypt foci, an important marker currently used to estimate the efficacy of colon cancer chemoprevention agents. In humans, wheat bran fiber has been shown to consistently decrease fecal bile acid concentrations, mainly by reducing toxic secondary bile acids.