title: L-glutamine and whole protein restore first-phase insulin response and increase glucagon-like peptide-1 in type 2 diabetes patients.
abstract: 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.
authors: Diabetes & Metabolism Division, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst 2010, Sydney, NSW, Australia. d.samochabonet@garvan.org.au.|Faculty of Medicine, UNSW Australia, High Street, Kensington 2052, Sydney, NSW, Australia. d.samochabonet@garvan.org.au.
authors: Dorit
authors: D
authors: Samocha-Bonet
authors: Diabetes & Metabolism Division, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst 2010, Sydney, NSW, Australia. d.chisholm@garvan.org.au.
authors: Don J
authors: DJ
authors: Chisholm
authors: NNF Center for Basic Metabolic Research, Department of Biomedical Sciences, University of Copenhagen, Panum Institute, Nørregade 10, DK-1165 Copenhagen, Denmark. jjholst@sund.ku.dk.
authors: Jens J
authors: JJ
authors: Holst
authors: Diabetes & Metabolism Division, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst 2010, Sydney, NSW, Australia. j.greenfield@garvan.org.au.|Faculty of Medicine, UNSW Australia, High Street, Kensington 2052, Sydney, NSW, Australia. j.greenfield@garvan.org.au.|Department of Endocrinology and Diabetes Center, St. Vincent's Hospital, 390 Victoria Street, Darlinghurst 2010, Sydney, NSW, Australia. j.greenfield@garvan.org.au.
authors: Jerry R
authors: JR
authors: Greenfield
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D018592:Cross-Over Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000188:drug therapy*; D004044:Dietary Proteins / Q000008:administration & dosage*; D005260:Female; D052216:Glucagon-Like Peptide 1 / Q000097:blood*; D005973:Glutamine / Q000008:administration & dosage*; D006801:Humans; D007328:Insulin / Q000097:blood*; D008297:Male; D008875:Middle Aged
chemical_list: D001786:Blood Glucose; D004044:Dietary Proteins; D007328:Insulin; D005973:Glutamine; D052216:Glucagon-Like Peptide 1