Dietary wheat bran lowers colonic pH in rats

The effect of chronic dietary wheat bran supplementation on the pH of gastrointestinal contents was examined in thirty-one Sprague-Dawley rats. Ten control rats received a fiber-free diet while twenty-one rats were fed the same diet plus a 20% wheat bran supplement. The fiber-fed rats developed a greater acidity of intestinal contents: cecal pH was 6.30 +/- 0.33 in the controls (P less than 0.01). These changes in gastrointestinal pH may be of relevance to the nutrient modulation of gastric and colonic tumor development.