title: Vitamin E supplementation and plasma 8-isoprostane and adiponectin in overweight subjects.
abstract: OBJECTIVE
  Isoprostanes are a marker of oxidant stress and atherosclerotic risk, and plasma concentrations are elevated in obesity. Adiponectin is a regulator of insulin sensitivity, and low circulating levels are associated with oxidant stress and obesity. The aim of this study was to determine the effect of vitamin E supplementation on plasma concentrations of 8-isoprostane and adiponectin in overweight/obese subjects.
  
  
  METHODS
  The study was a 6-month, randomized, double-blind, placebo-controlled trial in 80 overweight subjects (60 women and 20 men, BMI >27 kg/m(2)). Exclusion criteria were serious illness, smoking, or taking antioxidant supplements. Participants were randomized to receive 800 IU/d natural vitamin E (n = 39) or placebo (n = 41) for 3 months with an increase in the dose to 1200 IU/d for a further 3 months. Plasma 8-isoprostane and adiponectin concentrations were measured at baseline and 3 and 6 months.
  
  
  RESULTS
  During 6 months of supplementation with vitamin E, plasma vitamin E concentration increased significantly (p < 0.001) by 76%, and plasma 8-isoprostane concentrations decreased significantly (-11%, p = 0.03), whereas plasma adiponectin concentrations did not change significantly.
  
  
  CONCLUSIONS
  These findings suggest that supplementation with high-dose vitamin E decreases systemic oxidative stress and 8-isoprostane concentrations in overweight/obese individuals. A decrease in plasma 8-isoprostane has the potential to reduce risk of cardiovascular disease in obesity.
authors.affiliation: Medicine Section, Department of Medical and Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand. wayne.Sutherland@stonebow.otago.ac.nz
authors.forename: Wayne H F
authors.initials: WH
authors.lastname: Sutherland
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Manning
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Walker
authors.forename: Sylvia A
authors.initials: SA
authors.lastname: de Jong
authors.forename: Anne R
authors.initials: AR
authors.lastname: Ryalls
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Berry
mesh_terms: D052242:Adiponectin / Q000097:blood; D000328:Adult; D000368:Aged; D019587:Dietary Supplements; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000097:blood; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D050177:Overweight; D018384:Oxidative Stress / Q000187:drug effects*; D010919:Placebos; D014810:Vitamin E / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: C499918:ADIPOQ protein, human; D052242:Adiponectin; D010919:Placebos; D014810:Vitamin E; C075750:8-epi-prostaglandin F2alpha; D015237:Dinoprost