Glutamine Supplementation of Enteral Nutrition: Impact on Whole Body Protein Kinetics and Glucose Metabolism in Critically Ill Patients

Background: Glutamine-supplemented parenteral nutrition has been reported to attenuate the early postoperative reduction in intracellular glutamine and improve protein synthesis and nitrogen balance. We investigated the effect of an enteral formula on protein and glucose kinetics and nitrogen balance in trauma patients. Methods: The enteral formula (AlitraQ) provided a mean intake of 0.35 g of glutamine/kg body weight per day to 16 trauma patients and was compared with an isonitrogenous formula that provided a mean of 0.05 g of glutamine/kg body weight per day in 14 trauma patients. After 3 days of feeding, protein kinetics were measured using a 4-hour prime-continuous infusion Of L-[1-13C]leucine. Glucose kinetics were measured during the same time interval using prime-continuous infusion of [U-14C]- and [6-3H]glucose. Results: Nitrogen balance was not significantly different in the two groups. There were no significant differences in protein turnover, synthesis, and breakdown between the two groups. There were no significant differences in glucose turnover, oxidation, recycling, and percent Of VCO2 from glucose oxidation between the two groups. Conclusions: Glutamine-enriched enteral formulas are well tolerated by the severely injured patient but provide no additional nutritional advantage compared with standard enteral formulas during the first 3 days of feeding immediately after trauma. (Journal of Parenteral and Enteral Nutrition 19:470-476, 1995)