Effect of glutamine-supplemented parenteral nutrition on mortality in critically ill patients.

Glutamine is recognized as a critical amino acid involved in immunity, intestinal health, and nitrogen transport between organs. Prior to the pivotal study by Griffiths and colleagues in 1997, no clinical trials had demonstrated a positive effect from glutamine supplementation on improving long-term survival in critically ill intensive care unit patients receiving parenteral nutrition. Subsequent investigations have confirmed these findings, but further data are needed to determine the optimal dose and timing of glutamine as well as the form of glutamine (ie, free vs dipeptide) that produces the most significant improvement in outcome parameters.