Functional gut problems such as IBS remain a considerable challenge to both clinician and patient. Finding safe and simple interventions as therapeutic strategies is an important part of ongoing research. Many practitioners are familiar with the use of the amino acid L-glutamine as a nutrient that confers benefit to gastro intestinal tracts experiencing increased levels of permeability and translocation of immune activating components such as LPS.
The journal Gut in August 2018 published a paper, the abstract of which is below confirming that for people with post infectious IBS glutamine provided considerable benefits and that further large-scale trials should be actioned.
BACKGROUND: More effective treatments are needed for patients with postinfectious, diarrhoea-predominant, irritable bowel syndrome (IBS-D). Accordingly, we conducted a randomised, double-blind, placebo-controlled, 8-week-long trial to assess the efficacy and safety of oral glutamine therapy in patients who developed IBS-D with increased intestinal permeability following an enteric infection.
METHODS: Eligible adults were randomised to glutamine (5 g/t.i.d.) or placebo for 8 weeks. The primary end point was a reduction of =50 points on the Irritable Bowel Syndrome Severity Scoring System (IBS-SS). Secondary endpoints included: raw IBS-SS scores, changes in daily bowel movement frequency, stool form (Bristol Stool Scale) and intestinal permeability.
RESULTS: Fifty-four glutamine and 52 placebo subjects completed the 8-week study. The primary endpoint occurred in 43 (79.6%) in the glutamine group and 3 (5.8%) in the placebo group (a 14-fold difference). Glutamine also reduced all secondary endpoint means: IBS-SS score at 8 weeks (301 vs 181, p<0.0001), daily bowel movement frequency (5.4 vs 2.9±1.0, p<0.0001), Bristol Stool Scale (6.5 vs 3.9, p<0.0001) and intestinal permeability (0.11 vs 0.05; p<0.0001). ‘Intestinal hyperpermeability’ (elevated urinary lactulose/mannitol ratios) was normalised 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.
CONCLUSIONS: In patients with IBS-D with intestinal hyperpermeability following an enteric infection, oral dietary glutamine supplements dramatically and safely reduced all major IBS-related endpoints. Large randomised clinical trials (RCTs) should now be done to validate these findings, assess quality of life benefits and explore pharmacological mechanisms.
 Zhou Q, Verne ML, Fields JZ, Lefante JJ, Basra S, Salameh H, Verne GN Randomised placebo-controlled trial of dietary glutamine supplements for postinfectious irritable bowel syndrome. Gut. 2018 Aug 14. View Abstract