Adding more fluid to wheat bran has no significant effects on intestinal functions of healthy subjects

To regulate intestinal transit, increased fluid intake, along with fiber is recommended. Considering the usually large volumes of intestinal secretion, this advice is questionable. To demonstrate the effects of adding fluid to fiber, 11 volunteers ingested 15 g of wheat bran twice a day, randomly given without or with 600 mL of additional fluid. Stool weight and frequency were similarly increased in the two settings. Gastric emptying was delayed by bran only when bran was given without additional fluid. Orocecal transit showed no significant changes. Whole gut transit was slightly more accelerated with added fluid (20.6 vs. 13.5%). No test showed significant differences in direct comparison of bran and bran with additional fluid. We conclude that in healthy persons, such effects of wheat bran as acceleration of transit and increase in stool weight and frequency do not depend on an additional intake of fluid.