This site keeps its references apart from each section, which makes it a bit confusing. I’d like to know the dates of the research it is siting without having to go hunting. Oh well, probably not the best source.

Amplify’d from
The amino acid glutamine is the preferred
fuel for small intestinal enterocytes and can decrease
intestinal permeability, a potential benefit
for Crohns Disease patients.
Despite theoretical indications for
glutamine supplementation in Crohn’s Disease, several small
intervention trials have not yielded benefit. In a
double-blind study to determine if glutamine decreases
gut permeability in Crohn’s disease, 14
Crohn’s Disease patients were randomly assigned to receive 7
g glutamine or placebo (glycine) three times daily
along with their conventional treatment. There
were no significant changes in permeability during
the four-week trial in either the glutamine or
placebo groups. In addition, no significant changes
were seen in CDAI, CRP, or plasma glutamine/
glutamate levels.248