A small randomized, double-blind, placebo-controlled trial in the US showed that oral dietary glutamine supplements effective and safe in patients with diarrhea-predominant irritable bowel syndrome (IBS-D) with intestinal hyperpermeability following an enteric infection. Participants (mean age 31.7, approximately 70% women, and 80% white) were randomized to glutamine (5 g/t.i.d.) or placebo for 8 weeks from 2011 to 2015. Fifty-four glutamine and 52 placebo subjects completed the study. The primary endpoint (reduction of ≥50 points on the Irritable Bowel Syndrome Severity Scoring System [IBS-SS]) occurred in 43 (79.6%) in the glutamine group and 3 (5.8%) in the placebo group. Glutamine also reduced all secondary endpoint means: IBS-SS score at 8 weeks (301 vs 181), daily bowel movement frequency (5.4 vs 2.9±1.0), Bristol Stool Scale (6.5 vs 3.9) and intestinal permeability (0.11 vs 0.05). ‘Intestinal hyperpermeability’ (elevated urinary lactulose/mannitol ratios) was normalized in the glutamine but not the control group. Adverse events and rates of study-drug discontinuation were low and similar in the two groups. No serious adverse events were observed. Glutamine is the main energy source for the rapidly dividing epithelial cells of the gut, any depletion can lead to hyperpermeability. Source: https://gut.bmj.com/
