No abstract

Short-chain fatty acids (SCFA) in faeces were examined in 18 patients with the irritable bowel syndrome (IBS) during treatment with wheat bran or placebo. In the placebo period, the patients could be classified in accordance with the faecal concentrations of SCFA into one group with low concentrations (mean, 40 mmol/l; range, 19-77 mmol/l; 10 patients) and another with high concentrations (mean, 168 mmol/l; range, 145-187 mmol/l; 8 patients). The concentrations of SCFA differed (P less than 0.001) in both groups from concentrations found in faeces from a reference group of nine normal individuals (mean, 114 mmol/l; range, 93-155 mmol/l). Patients with low levels of SCFA had lower (P less than 0.001) mean stool mass and longer (P less than 0.05) transit times than those with high concentrations of SCFA in faeces. Ingestion of bran, although a precursor of SCFA, did not change faecal concentrations of SCFA. Abdominal pain, distension, and rumbling were not correlated to low or high concentrations of SCFA in faeces, nor did bran improve these symptoms when compared to placebo. The level of SCFA was rather constant intraindividually and independent of the variability of the daily faecal mass. It is concluded that patients with IBS apparently have continuously abnormal concentrations of SCFA in faeces, either high or low, which are unaffected by the treatment with bran and which hypothetically may be of pathophysiologic importance.

Dietary supplementation with wheat bran has been widely advocated as a first-line treatment of patients with the irritable bowel syndrome (IBS). Few controlled trials have been reported, and the results are, furthermore, contradictory. The present study comprised 20 patients with IBS, of whom 18 (14 women, 4 men) completed the trial. The two treatment periods of 6 weeks each, with a daily intake of 30 g coarse wheat bran or 30 g placebo bran, respectively, were randomized in a double-blind cross-over design. Wheat bran significantly (P less than 0.05) increased the stool weight and shortened the intestinal transit time but was without significant effect on the colonic motility index was shown. We conclude that coarse wheat bran used as the only treatment in IBS does not provide a sufficient effect in a 6-week period. However, wheat bran seems to be justified in the treatment of constipation.