ABSTRACT
The use of glutamine supplementation in critical illness may have three different rationales. First, to be a part of the amino acid content of an optimal protein supply. Second, to aim at restoring a possible shortage or deficit as evidenced by low plasma and/or tissue concentrations. Third, to be given with the purpose of having pharmacological effects by itself or in combination with other substances. The different handling of glutamine related to the route of administration must of course be taken into consideration when the clinical effects of glutamine supplementation are discussed. In critically ill subjects, the degree of glutamine depletion in terms of low intracellular concentration in muscle is more pronounced as compared to postoperative patients. The difficulty in conjunction with glutamine supplementation is the absence of any direct connection between hypoglutaminemia or hyperglutaminemia, and mortality. The hypothesis that glutamine availability is crucial for regeneration of intestinal mucosa has emerged from animal experiments.
