Glutamine for induction of remission in Crohn's disease.

Systematic review of 2 small randomized controlled trials in active Crohn's disease and acute exacerbations of inflammatory bowel disease. One trial enrolled children 6 to 16 years old with active Crohn's disease in the United Kingdom, and the other enrolled adults older than 18 years in Germany; across the active intervention arms, 21 participants were randomized.

Glutamine was tested in two active-regimen forms: a glutamine-enriched polymeric diet given orally or by fine-bore nasogastric tube for 4 weeks in children, and alanyl-glutamine added to total parenteral nutrition at 0.3 g/kg/day for at least 1 week in adults. The adult trial compared glutamine-supplemented TPN with standard TPN without glutamine; all patients also received mesalazine.

Glutamine did not show clear efficacy for inducing remission in active Crohn's disease, and the overall evidence base was too small to establish safety or benefit. In the pediatric trial, remission at 4 weeks was 4/9 with glutamine diet versus 5/9 with standard diet (RR 0.80, 95% CI 0.31 to 2.04), and the between-group difference in intestinal permeability change was not significant (P = 0.239). In the adult trial, the change in lactulose/xylose ratio after 1 week was also not significantly different (MD -0.01, 95% CI -0.04 to 0.02). Safety conclusions were uncertain; no serious adverse events were reported in the pediatric study, while the adult study reported three central catheter infections in the glutamine group versus none in control (RR 7.00, 95% CI 0.40 to 122.44).

The evidence comes from only 2 small single-center trials with different populations, formulations, and routes of administration, limiting comparability and precision. Sample sizes were very small, confidence intervals were wide, and follow-up was short, so clinically important benefit or harm cannot be ruled out. Safety data were sparse and indirect for broader Crohn's disease populations.