Using Evidence to Get the Most Out of Dietary Interventions in Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a chronic disorder of gut–brain interaction characterized by abdominal pain and abnormal stool form or frequency. IBS symptoms often commence after, or are exacerbated by, eating. People with IBS are, therefore, increasingly interested in the role of food or dietary constituents in triggering their symptoms and often express a preference for dietary management over drug therapy. Partly as a result, there has been an explosion in interest around dietary interventions in IBS over the last 20 years. This article discusses how the quality of randomized controlled trials (RCTs) is judged conventionally and how this can “shortchange” whole dietary intervention trials in IBS. The design of trials of active whole dietary interventions in IBS, including the selection of a comparator or a credible control intervention, is described. Finally, the article summarizes the evidence for fiber supplementation and whole dietary interventions in IBS, focusing on the results of RCTs and meta-analyses, with more recent developments also reported.