L-glutamine and whole protein restore first-phase insulin response and increase glucagon-like Peptide-1 in type 2 diabetes patients
l-glutamine triggers glucagon-like peptide-1 (GLP-1) release from L cells in vitro and when ingested pre-meal, decreases postprandial glycaemia and increases circulating insulin and GLP-1 in type 2 diabetes (T2D) patients. We aimed to evaluate the effect of oral l-glutamine, compared with whole protein low in glutamine, on insulin response in well-controlled T2D patients. In a randomized study with a crossover design, T2D patients (n = 10, 6 men) aged 65.1 +/- 5.8, with glycosylated hemoglobin (HbA1c) 6.6% +/- 0.7% (48 +/- 8 mmol/mol), received oral l-glutamine (25 g), protein (25 g) or water, followed by an intravenous glucose bolus (0.3 g/kg) and hyperglycemic glucose clamp for 2 h. Blood was frequently collected for analyses of glucose, serum insulin and plasma total and active GLP-1 and area under the curve of glucose, insulin, total and active GLP-1 excursions calculated. Treatments were tested 1-2 weeks apart. Both l-glutamine and protein increased first-phase insulin response (p </= 0.02). Protein (p = 0.05), but not l-glutamine (p = 0.2), increased second-phase insulin response. Total GLP-1 was increased by both l-glutamine and protein (p </= 0.02). We conclude that oral l-glutamine and whole protein are similarly effective in restoring first-phase insulin response in T2D patients. Larger studies are required to further investigate the utility of similar approaches in improving insulin response in diabetes.
|ISBN||2072-6643 (Electronic) 2072-6643 (Linking)|
|Authors||Samocha-Bonet, D.; Chisholm, D. J.; Holst, J. J.; Greenfield, J. R.;|
|Responsible Garvan Author|
|URL link to publisher's version||http://www.ncbi.nlm.nih.gov/pubmed/25811109|
|OpenAccess link to author's accepted manuscript version||https://publications.gimr.garvan.org.au/open-access/12886|