Effect of wheat bran in treatment of chronic nonorganic constipation. A double-blind controlled trial.

After a two-week basal period, 24 patients were randomly allocated to receive, with a crossover double-blind design, for two consecutive four-week periods, bran (20 g/24 hr) or placebo. The daily intake of water and dietary fibers was standardized. Symptomatology, oroanal transit time, bowel frequency, and stool weight were assessed in basal conditions and at week 4 and 8 of the treatment. Oroanal transit time decreased and bowel frequency and stool weight increased significantly during both bran and placebo administration in comparison with basal period. Bran treatment was more effective than placebo in improving bowel frequency and oroanal transit. During bran treatment oroanal transit time became normal only in patients with slow colonic transit and not in those with slow rectal transit. Neither the occurrence nor the severity of the most frequent accompanying symptoms of chronic constipation differed significantly between placebo and bran treatments.