Glycemic Effects and Safety of L-Glutamine Supplementation with or without Sitagliptin in Type 2 Diabetes Patients—A Randomized Study
What this study found
Daily L-glutamine improved glycemic markers over 4 weeks, with or without sitagliptin, and the authors concluded that the effect was generally favorable with limited short-term safety concerns. HbA1c fell from 7.0% to 6.9% with glutamine plus placebo and from 6.9% to 6.7% with glutamine plus sitagliptin; fructosamine also decreased in both periods (258 to 244 mmol/L and 246 to 240 mmol/L). Postprandial glucose AUC decreased (P = 0.008), while total GLP-1 AUC and active GLP-1 AUC increased (both P values reported as 0.008 or <0.001); the sitagliptin period showed a greater fasting glucose…
- Study & population
- Randomized crossover study in adults with well-controlled type 2 diabetes treated with metformin, conducted in Australia at St Vincent's Hospital Sydney.
- Intervention
- L-glutamine was given orally at 15 g twice daily for 4 weeks, taken about 15 minutes before breakfast and again before dinner.
- Key limitation
- Small sample size with only 13 completers, short 4-week treatment periods, and a crossover design limit precision and generalizability.
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Open PDFOriginal abstract
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