Although irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders presenting to gastroenterologists, therapeutic strategies are not yet well established. Accordingly, we conducted a randomized, double-blind, placebo controlled, clinical trial to evaluate the possible superiority of adding glutamine supplement to low fermentable oligo- di- mono- saccharides and polyols (FODMAP) diet in patients with IBS.

Eligible adults were randomized to receive a low FODMAP diet either with glutamine (15 gram/day) or a placebo for 6 weeks. The primary end point was a significant reduction in IBS-symptom severity score (IBS-SSS). Secondary end points were changes in IBS symptoms, bowel habits and quality of life.

Fifty patients were enrolled in the study, and 22 participants from each group completed the study protocol. The glutamine group had significant changes in total IBS-severity score (-180±60.57; p=0.014), dissatisfaction with bowel habit (-38.18±18.55; p <0.001) and abdominal pain frequency (-32.73±22.08; p=.043). Improvement in IBS-severity score of more than 45% was observed in 22 of 25 participants (88%) in glutamine group, while it was only 15 of 25 participants (60%) in the control group (p=0.015). No serious adverse events were observed.

Our findings indicate the superiority of adding glutamine supplementation to low FODMAP diet in amelioration of IBS symptoms, while confirming the beneficial effects of low FODMAP diet in IBS management.