title: Identification of differential responses to an oral glucose tolerance test in healthy adults.
abstract: BACKGROUND
  In recent years an individual's ability to respond to an acute dietary challenge has emerged as a measure of their biological flexibility. Analysis of such responses has been proposed to be an indicator of health status. However, for this to be fully realised further work on differential responses to nutritional challenge is needed. This study examined whether metabolic phenotyping could identify differential responders to an oral glucose tolerance test (OGTT) and examined the phenotypic basis of the response.
  
  
  RESULTS
  A total of 214 individuals were recruited and underwent challenge tests in the form of an OGTT and an oral lipid tolerance test (OLTT). Detailed biochemical parameters, body composition and fitness tests were recorded. Mixed model clustering was employed to define 4 metabotypes consisting of 4 different responses to an OGTT. Cluster 1 was of particular interest, with this metabotype having the highest BMI, triacylglycerol, hsCRP, c-peptide, insulin and HOMA- IR score and lowest VO2max. Cluster 1 had a reduced beta cell function and a differential response to insulin and c-peptide during an OGTT. Additionally, cluster 1 displayed a differential response to the OLTT.
  
  
  CONCLUSIONS
  This work demonstrated that there were four distinct metabolic responses to the OGTT. Classification of subjects based on their response curves revealed an "at risk" metabolic phenotype.
authors.affiliation: UCD Institute of Food and Health, University College Dublin, Belfield, Dublin, Rep. of Ireland.
authors.forename: Ciara
authors.initials: C
authors.lastname: Morris
authors.forename: Colm
authors.initials: C
authors.lastname: O'Grada
authors.forename: Miriam
authors.initials: M
authors.lastname: Ryan
authors.forename: Helen M
authors.initials: HM
authors.lastname: Roche
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Gibney
authors.forename: Eileen R
authors.initials: ER
authors.lastname: Gibney
authors.forename: Lorraine
authors.initials: L
authors.lastname: Brennan
mesh_terms: D000328:Adult; D005260:Female; D005951:Glucose Tolerance Test; D064368:Healthy Volunteers; D006801:Humans; D007333:Insulin Resistance; D007515:Islets of Langerhans / Q000502:physiology; D008297:Male