Samocha-Bonet, Dorit2; Chisholm, Donald J2; Gribble, Fiona M2; Coster, Adelle C F2; Carpenter, Kevin H2; Jones, Graham R D2; Holst, Jens Juul4; Greenfield, Jerry R2
1 Section of Endocrinology Research, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Københavns Universitet2 unknown3 Section for Translational Metabolic Physiology, The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, Københavns Universitet4 Section for Translational Metabolic Physiology, The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, Københavns Universitet
BACKGROUND AND AIMS: L-glutamine is an efficacious glucagon-like peptide (GLP)-1 secretagogue in vitro. When administered with a meal, glutamine increases GLP-1 and insulin excursions and reduces postprandial glycaemia in type 2 diabetes patients. The aim of the study was to assess the efficacy and safety of daily glutamine supplementation with or without the dipeptidyl peptidase (DPP)-4 inhibitor sitagliptin in well-controlled type 2 diabetes patients. METHODS: Type 2 diabetes patients treated with metformin (n = 13, 9 men) with baseline glycated hemoglobin (HbA1c) 7.1±0.3% (54±4 mmol/mol) received glutamine (15 g bd)+ sitagliptin (100 mg/d) or glutamine (15 g bd) + placebo for 4 weeks in a randomized crossover study. RESULTS: HbA1c (P = 0.007) and fructosamine (P = 0.02) decreased modestly, without significant time-treatment interactions (both P = 0.4). Blood urea increased (P<0.001) without a significant time-treatment interaction (P = 0.8), but creatinine and estimated glomerular filtration rate (eGFR) were unchanged (P≥0.5). Red blood cells, hemoglobin, hematocrit, and albumin modestly decreased (P≤0.02), without significant time-treatment interactions (P≥0.4). Body weight and plasma electrolytes remained unchanged (P≥0.2). CONCLUSIONS: Daily oral supplementation of glutamine with or without sitagliptin for 4 weeks decreased glycaemia in well-controlled type 2 diabetes patients, but was also associated with mild plasma volume expansion. TRIAL REGISTRATION: ClincalTrials.gov NCT00673894.