THE ROLE OF GLUTAMINE IN NUTRITION

The nonessential amino acid glutamine is the major carrier of circulating nitrogen between tissues and occupies an important position in numerous metabolic pathways. Glutamine is also an essential substrate for rapidly dividing cells, which utilize glutamine as a source of energy, and is a substrate for nucleotide synthesis. The metabolic alterations associated with critical illness result in an increased requirement for glutamine by various tissues that exceeds endogenous synthetic capacity, producing a relative deficiency of this amino acid. This provides the basis for the hypothesis that glutamine is a conditionally essential amino acid. A substantial body of research is currently aimed at defining the efficacy of glutamine-enriched nutritional support regimens.