Effects of Dietary Supplements of Wheat Bran and Cellulose on Faeces and Bowel Function

TLDR

Four weeks of 16 g/day wheat bran or cellulose was added to the diet of normal subjects to assess bowel function. The supplements increased stool weight, did not alter intestinal transit time, diluted faecal bile acids, and produced a bulky stool that likely underlies any symptomatic benefit.

Abstract

In a study of bowel function in normal subjects wheat bran or cellulose was added to the diet for four weeks (16 g/day). Stool weight increased. Intestinal transit time did not significantly alter. Faecal bile acids did not increase but were diluted. It seems that the effect of these materials is to produce a bulky stool and that any symptomatic benefit they produce is secondary to this.