The effect of low FODMAP diet with and without gluten on irritable bowel syndrome: A double blind, placebo controlled randomized clinical trial

Background & aim: Although the effects of low fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) diet on amelioration of irritable bowel syndrome (IBS) symptoms have been reported previously, it has not yet been elucidated whether the gluten of wheat and barley induces the symptoms or only their fructans lead to aggravation of the symptoms. The aim of this study was to assess the effect of low FODMAPs diet with vs. without gluten on clinical symptoms in IBS patients. Methods: In this double-blind, placebo-controlled randomized trial, forty nine IBS patients were randomly assigned to placebo and/or intervention group. Patients in the intervention group received 5 gr/day of gluten powder with low FODMAP diet, while placebo group received 5 gr of rice flour as placebo, with low FODMAP diet. Quality of life (QoL) and IBS-SSS (symptom severity score) were measured before and after the intervention using a valid QoL questionnaire and a standard visual analog scale, respectively. Results: Significant improvements were observed in total scores of IBS-SSS (-32% vs. - 49%), abdominal pain intensity (-45% vs. -52%), and frequency (-26 vs. -46%), abdominal distension (-29% vs. -63%), Interference with community function (-14% vs. -45%) and quality of life (+23 vs. +32%) in both gluten and placebo groups respectively (P < 0.05). Only 5 patients in the gluten-containing diet reported exacerbation of their symptoms. Conclusion: Exacerbation of IBS symptoms after wheat and barley consumption is due to their fructan, and not related to their gluten content in most of the patients. (C) 2021 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved.