Systematic review: the effects of fibre in the management of chronic idiopathic constipation.Aliment Pharmacol Ther. 2011 Apr; 33(8):895-901.AP
Patients with chronic idiopathic constipation are often told to increase dietary fibre intake. Whether this is of any benefit remains unclear.
To conduct a systematic review of the efficacy of soluble and insoluble fibre supplementation in the management of chronic idiopathic constipation.
MEDLINE, EMBASE, and the Cochrane central register of controlled trials were searched to identify randomised controlled trials (RCTs) comparing fibre with placebo or no therapy in adult chronic idiopathic constipation patients. Studies had to report dichotomous data assessing response to therapy, or continuous data examining either effect of therapy on mean number of stools per week, or mean symptom scores. Adverse events data were extracted where reported.
Six RCTs were eligible. Four used soluble fibre and two used insoluble fibre. Formal meta-analysis was not undertaken due to concern about methodological quality of identified studies. Compared with placebo, soluble fibre led to improvements in global symptoms (86.5% vs. 47.4%), straining (55.6% vs. 28.6%), pain on defaecation, and stool consistency, an increase in the mean number of stools per week (3.8 stools per week after therapy compared with 2.9 stools per week at baseline), and a reduction in the number of days between stools. Evidence for any benefit of insoluble fibre was conflicting. Adverse events data were limited, with no RCT reporting total numbers.
Soluble fibre may be of benefit in chronic idiopathic constipation, but data for insoluble fibre are conflicting. More data from high quality RCTs are required before the true efficacy of either fibre type in the treatment of chronic idiopathic constipation is known.