Influence of polymeric enteral nutrition supplemented with different doses of glutamine on gut permeability in critically ill patients

OBJECTIVES: To evaluate the effect of glutamine-supplemented polymeric enteral formulas on the recovery of gut-permeability abnormalities in critically ill patients. METHODS: Twenty-three patients were randomized to receive a conventional casein-based enteral formula (ADN), ADN plus glutamine in a dose of 0.15 g · kg −1 · d −1 or ADN plus 0.30 g · kg −1 · d −1 of glutamine for 8 d. The lactulose mannitol permeability test (L/M) was performed at baseline and at the end of the study. Nineteen healthy volunteers served as controls for the L/M test. RESULTS: An increase in permeability compared with control subjects was observed in patients at baseline (mean ± standard error of the mean; L/M ratio: 0.11 ± 0.03 and 0.025 ± 0.004, respectively; P < 0.02). The L/M ratio improved after the period of enteral nutrition as a whole (initial L/M: 0.11 ± 0.03, final L/M: 0.061 ± 0.01; P < 0.03), but no difference was found between groups. CONCLUSIONS: Even though polymeric enteral nutrition was associated with a significant improvement in the L/M ratio, glutamine supplementation did not show a specific influence in improving recovery of gut permeability in critically ill patients.