Clinical question Which is more effective and better tolerated in the treatment of irritable bowel syndrome (IBS): high fibre supplements or guar gum?
Synopsis High fibre diets are commonly recommended to patients with irritable bowel syndrome, although many are not able to tolerate fibre. Guar gum is a water soluble polysaccharide that is extremely viscous and difficult to incorporate into food. Thus, it must be used as a partially hydrolysed guar gum (PHGG) in beverage form. PHGG has proved effective in softening and improving fecal output. In this non-blinded randomised controlled trial, patients (188 adults, mean age 40 years) with chronic irritable bowel syndrome were divided into three groups: diarrhoea-predominant, constipation-predominant, and mixed. After randomisation (allocation assignment not concealed), patients were instructed on supplementing their diet with 30 g/day supplement of wheat bran or a beverage containing 5 g/day of PHGG, taken shortly before breakfast. Patients were followed for a total of 12 weeks, but after the first four weeks they were given the option to switch groups if desired. An intention to treat analysis was used, meaning that patients who switched over to another group were considered as treatment failures.. More patients switched from fibre to PHGG than from PHGG to fibre (50% v 11%; P<0.001), with more patients switching from the mixed group (47%) than the diarrhoea-predominant group (30%) and the constipation-predominant group (23%). After eight weeks, no differences were found for abdominal pain scores or in the prevalence of an improvement in altered bowel habits across the three bowel habit groups or between the fibre and PHGG groups. Outcomes were self assessed by patients, who were not blinded to treatment assignment.
Bottom line Fibre supplemented diet and guar gum supplementation equally improved symptoms of irritable bowel syndrome. Hydrolysed guar gum was preferred by more patients and should be considered when patients with the syndrome can't tolerate fibre or report a worsening of their symptoms with fibre.
Level of evidence 2b (www.infopoems.com/levelsofevidence.cfm)
Footnotes
©infoPOEMs 1992-2002 www.infoPOEMs.com * Patient-Oriented Evidence that Matters. See editorial (BMJ 2002;325:983)
References
- Parisi GC, Zilli M, Miani MP, et al. High-fiber diet supplementation in patients with irritable bowel syndrome (IBS). A multicenter, randomized, open trial comparison between wheat bran diet and partially hydrolyzed guar gum (PHGG) Digestive Diseases and Sciences. 2002;47:1697–1704. doi: 10.1023/a:1016419906546. [DOI] [PubMed] [Google Scholar]