Parenteral glutamine dipeptide improves nitrogen balance in postoperat
ive patients on total parenteral nutrition (TPM). Animal studies show
that the structure and function of the gut is preserved by glutamine.
It is not known if this is the case in human beings. 20 patients admit
ted to hospital for total parenteral nutrition were randomly allocated
to receive parenteral nutrition enriched with glycyl-L-glutamine (Gln
TPN), or standard parenteral nutrition (STPN). Mucosal biopsy specime
ns were taken from the second part of the duodenum before starting par
enteral nutrition, and after two weeks. The ratio between the urine co
ncentrations of lactulose and mannitol after enteral administration wa
s used to measure intestinal permeability. After two weeks of parenter
al nutrition in the GlnTPN group, intestinal permeability was unchange
d, whereas permeability in the STPN group increased. Villus height was
unaltered in the GlnTPN group but in the STPN group it decreased. The
addition of glutamine to parenteral nutrition prevents deterioration
of gut permeability and preserves mucosal structure.