title: Fruit and vegetable intake and the association with glucose parameters: a cross-sectional analysis of the Let's Prevent Diabetes Study.
abstract: BACKGROUND
  Dietary recommendations for the prevention of type 2 diabetes mellitus include the message to consume 400 g fruit and vegetables per day. Measurement of habitual diet is inherently difficult, yet errors due to self-report can be eliminated by the use of nutritional biomarkers. The aim of this study was to determine plasma vitamin C concentrations as a biomarker for fruit and vegetable intake in individuals identified at high risk of diabetes. Fruit and vegetables may confer benefit via their antioxidant capacity, thus we also measured urinary F₂-isoprostanes as a marker for oxidative stress.
  
  
  METHODS
  Participants recruited from a high-risk population as part of a diabetes prevention trial provided fasting blood samples and a spot urine sample for the quantification of plasma vitamin C and F₂-isoprostanes, respectively. We compared glycaemic parameters by the increments of the standard deviation of plasma vitamin C using multiple regression models.
  
  
  RESULTS
  Mean plasma vitamin C of participants was 39.3 μmol/l (s.d. 21.8). In the unadjusted model, 1 s.d. plasma vitamin C was significantly and inversely associated with HbA1c, fasting and 2 h blood glucose (P ≤ 0.0001). Relationships remained significant after adjustment for demographic variables and confounding factors. No significant association was observed between plasma vitamin C and urinary F₂-isoprostanes.
  
  
  CONCLUSIONS
  The data adds to the evidence that small lifestyle changes may influence glucose regulation. The role that fruit and vegetables independently have should be investigated further.
authors.affiliation: Department of Cardiovascular Sciences, University of Leicester, Leicester, UK. Pc154@le.ac.uk
authors.forename: P
authors.initials: P
authors.lastname: Carter
authors.forename: L J
authors.initials: LJ
authors.lastname: Gray
authors.forename: D
authors.initials: D
authors.lastname: Talbot
authors.forename: D H
authors.initials: DH
authors.lastname: Morris
authors.forename: K
authors.initials: K
authors.lastname: Khunti
authors.forename: M J
authors.initials: MJ
authors.lastname: Davies
mesh_terms: D000328:Adult; D000368:Aged; D001205:Ascorbic Acid / Q000097:blood; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001786:Blood Glucose; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000453:epidemiology / Q000517:prevention & control* / Q000652:urine; D004739:England / Q000453:epidemiology; D028441:F2-Isoprostanes / Q000652:urine; D005260:Female; D005638:Fruit; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D012306:Risk; D012727:Sex Characteristics; D014675:Vegetables
chemical_list: D001205:Ascorbic Acid; D015415:Biomarkers; D001786:Blood Glucose; D028441:F2-Isoprostanes; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human