A randomized crossover study of the effects of glutamine and lipid on the gastric emptying time of a preoperative carbohydrate drink

Background & aims: Supplementing preoperative carbohydrate drinks with glutamine may lead to benefits in addition to reducing insulin resistance, but amino acids may delay gastric emptying (GE). The effects of supplementing a preoperative carbohydrate drink (CCD) with glutamine or lipid on GE were studied. Methods: Ten healthy male volunteers ingested 410 ml of one of three isocaloric-isovolumetric carbohydrate-based drinks labelled with Tc-99m-DTPA: CCD (preOp (R), Nutricia, UK, 50 g carbohydrate), CCD/G (preOp (R), 36 g carbohydrate + 15 g glutamine) or CCD/L (preOp (R), 36 g carbohydrate + 7 g lipid) in this randomized, blinded, three-way crossover study. After baseline measurements, GE was measured scintigraphically and blood sampled for insulin, glucose and glucagon-like peptide 1 (GLP-1) at 20 min intervals for 240 min. Results: Mean (95% Cl) T-90 GE times for CCD, CCD/G and CCD/L were 101 (87-115), 95 (84-107) and 87 (72-102) min, respectively. At 40 min postprandially, mean (SEM) concentrations of glucose (mmol/l) and insulin (mlU/l) were 7.5 (0.5) and 35 (5) for CCD; 6.2 (0.2) and 28 (4) for CCD/G; and 7(0.3) and 31 (5) for CCD/L, respectively. There were no differences in postprandial GLP-1 concentrations. Conclusions: Glutamine and lipid supplementation did not prolong the GE of CCD but did 'blunt' postprandial glucose and insulin responses, independent of GLP-1 concentrations. Registered under ClinicalTrials.gov Identifier no. NCT00943020. (C) 2010 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.