title: The effect of encapsulated glutamine on gut peptide secretion in human volunteers.
abstract: BACKGROUND
  Weight loss and improved blood glucose control after bariatric surgery have been attributed in part to increased ileal nutrient delivery with enhanced release of glucagon-like peptide 1 (GLP-1). Non-surgical strategies to manage obesity are required. The aim of the current study was to assess whether encapsulated glutamine, targeted to the ileum, could increase GLP-1 secretion, improve glucose tolerance or reduce meal size.
  
  
  METHODS
  A single-center, randomised, double blind, placebo-controlled, cross-over study was performed in 24 healthy volunteers and 8 patients with type 2 diabetes. Fasting participants received a single dose of encapsulated ileal-release glutamine (3.6 or 6.0 g) or placebo per visit with blood sampling at baseline and for 4h thereafter. Glucose tolerance and meal size were studied using a 75 g oral glucose tolerance test and ad libitum meal respectively.
  
  
  RESULTS
  In healthy volunteers, ingestion of 6.0 g glutamine was associated with increased GLP-1 concentrations after 90 min compared with placebo (mean 10.6 pg/ml vs 6.9 pg/ml, p=0.004), increased insulin concentrations after 90 min (mean 70.9 vs 48.5, p=0.048), and increased meal size at 120 min (mean 542 g eaten vs 481 g, p=0.008). Ingestion of 6.0 g glutamine was not associated with significant differences in GLP-1, glucose or insulin concentrations after a glucose tolerance test in healthy or type 2 diabetic participants.
  
  
  CONCLUSIONS
  Single oral dosing of encapsulated glutamine did not provoke consistent increases in GLP-1 and insulin secretion and was not associated with beneficial metabolic effects in healthy volunteers or patients with type 2 diabetes.
authors.affiliation: The Wellcome Trust-MRC Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Box 289, Hills Road, Cambridge CB2 0QQ, United Kingdom; Department of Clinical Biochemistry, Cambridge University Hospitals, Addenbrooke's Hospital, Box 281, Hills Road, Cambridge CB2 0QQ, United Kingdom.
authors.forename: Claire L
authors.initials: CL
authors.lastname: Meek
authors.affiliation: The Wellcome Trust-MRC Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Box 289, Hills Road, Cambridge CB2 0QQ, United Kingdom.
authors.forename: Hannah B
authors.initials: HB
authors.lastname: Lewis
authors.affiliation: The Wellcome Trust-MRC Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Box 289, Hills Road, Cambridge CB2 0QQ, United Kingdom.
authors.forename: Bensi
authors.initials: B
authors.lastname: Vergese
authors.affiliation: Department of Clinical Biochemistry, Cambridge University Hospitals, Addenbrooke's Hospital, Box 281, Hills Road, Cambridge CB2 0QQ, United Kingdom.
authors.forename: Adrian
authors.initials: A
authors.lastname: Park
authors.affiliation: The Wellcome Trust-MRC Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Box 289, Hills Road, Cambridge CB2 0QQ, United Kingdom.
authors.forename: Frank
authors.initials: F
authors.lastname: Reimann
authors.affiliation: The Wellcome Trust-MRC Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrooke's Hospital, Box 289, Hills Road, Cambridge CB2 0QQ, United Kingdom. Electronic address: fmg23@cam.ac.uk.
authors.forename: Fiona
authors.initials: F
authors.lastname: Gribble
mesh_terms: D000328:Adult; D000368:Aged; D001066:Appetite / Q000187:drug effects; D001067:Appetite Depressants / Q000008:administration & dosage*; D001786:Blood Glucose; D003924:Diabetes Mellitus, Type 2 / Q000097:blood; D004311:Double-Blind Method; D005260:Female; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D005951:Glucose Tolerance Test; D005973:Glutamine / Q000008:administration & dosage*; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D001067:Appetite Depressants; D001786:Blood Glucose; D007328:Insulin; D005973:Glutamine; D052216:Glucagon-Like Peptide 1
keywords: Glucagon-like peptide 1; Glutamine; Incretin; Insulin; Nutrients