title: Does vitamin C supplementation influence the levels of circulating oxidized LDL, sICAM-1, sVCAM-1 and vWF-antigen in healthy male smokers?
abstract: OBJECTIVE
  To examine the effects of vitamin C supplementation on the concentration of oxidation markers, in particular, circulating oxidized LDL (OxLDL) and on endothelial activation markers.
  
  
  METHODS
  Randomized double-blind, placebo-controlled crossover trial.
  
  
  METHODS
  Belgian population of the city of Leuven.
  
  
  METHODS
  A total of 34 healthy male smokers aged 26-73 y.
  
  
  METHODS
  Smokers were randomly assigned to receive either vitamin C (250 mg twice daily) or placebo capsules, each to be taken for 4 weeks. After a 1-week washout period, participants then crossed over to the alternative capsules for further 4 weeks.
  
  
  METHODS
  Markers of oxidation (bilirubin, uric acid, alpha-tocopherol, retinol, malondialdehyde, circulating Oxidized LDL (OxLDL)) and markers of endothelial activation (sICAM-1, sVCAM-1, vWF-antigen) were analysed.
  
  
  RESULTS
  Plasma ascorbate concentrations significantly increased from 46.6+/-17.6 to 70.1+/-21.2 mumol/l after a 4-week treatment with 500 mg vitamin C per day. The other plasma antioxidants concentrations, including bilirubin, uric acid, alpha-tocopherol and retinol, were similar in both treatment periods. Vitamin C did not change plasma malondialdehyde and circulating OxLDL compared with placebo (vitamin C 0.73+/-0.25 mg/dl OxLDL; placebo 0.72+/-0.21 mg/dl OxLDL). After vitamin C supplementation, neither sICAM-1 and sVCAM-1 levels nor the concentration of vWF-antigen significantly differed from placebo condition.
  
  
  CONCLUSIONS
  Oral supplementation of vitamin C is not associated with changes in markers of oxidation or endothelial activation in healthy male smokers.
authors.affiliation: Department of Public Health, Division of Nutritional Epidemiology, University of Leuven, Leuven, Belgium.
authors.forename: P G A
authors.initials: PG
authors.lastname: Van Hoydonck
authors.forename: E G
authors.initials: EG
authors.lastname: Schouten
authors.forename: B
authors.initials: B
authors.lastname: Manuel-Y-Keenoy
authors.forename: A
authors.initials: A
authors.lastname: van Campenhout
authors.forename: K P M
authors.initials: KP
authors.lastname: Hoppenbrouwers
authors.forename: E H M
authors.initials: EH
authors.lastname: Temme
mesh_terms: D000328:Adult; D000368:Aged; D000975:Antioxidants / Q000008:administration & dosage* / Q000378:metabolism; D001205:Ascorbic Acid / Q000008:administration & dosage* / Q000097:blood*; D018592:Cross-Over Studies; D019587:Dietary Supplements; D004311:Double-Blind Method; D004730:Endothelium, Vascular / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000097:blood; D008077:Lipoproteins, LDL / Q000097:blood; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction; D012907:Smoking / Q000097:blood / Q000378:metabolism*; D019010:Vascular Cell Adhesion Molecule-1 / Q000097:blood; D014841:von Willebrand Factor
chemical_list: D000975:Antioxidants; D008077:Lipoproteins, LDL; D019010:Vascular Cell Adhesion Molecule-1; C099252:oxidized low density lipoprotein; D014841:von Willebrand Factor; D018799:Intercellular Adhesion Molecule-1; D001205:Ascorbic Acid