title: Effect of orange juice intake on vitamin C concentrations and biomarkers of antioxidant status in humans.
abstract: BACKGROUND
  Consumption of fruit and vegetables is associated with improved health and a decreased prevalence of chronic degenerative processes.
  
  
  OBJECTIVE
  The objectives were to assess the bioavailability of vitamin C from orange juice and its influence on plasma vitamin C and 8-epi-prostaglandin F(2 alpha) (8-epi-PGF(2 alpha)) concentrations in a healthy human population.
  
  
  METHODS
  Six men and 6 women consumed 500 mL commercial fresh-squeezed orange juice/d for 14 d, corresponding to an intake of 250 mg ascorbic acid/d. On the first day of the study, the subjects drank the juice in one dose (dose-response study), and on days 2-14 they consumed 250 mL in the morning and 250 mL in the afternoon. Blood was collected every hour for 6 h on the first day and again on days 7 and 14.
  
  
  RESULTS
  Baseline plasma vitamin C concentrations were significantly higher (P = 0.03) among the women than among the men (56.4 +/- 4.4 compared with 44.3 +/- 3.5 micromol/L). In the dose-response study, the maximum increase in plasma vitamin C occurred 3 h postdose in both the men and the women. Vitamin C concentrations remained significantly higher on days 7 and 14 than at baseline. Baseline concentrations of 8-epi-PGF(2 alpha) were significantly higher (P = 0.03) among the men than among the women (249.6 +/- 25.4 compared with 177.7 +/- 6.2 pg/mL) but decreased significantly (P = 0.04) by day 14 of the intervention. A significant inverse correlation was observed between vitamin C and 8-epi-PGF(2 alpha) (r = -0.791, P = 0.0022). Among smokers, baseline vitamin C was lower and 8-epi-PGF(2 alpha) higher than among nonsmokers.
  
  
  CONCLUSIONS
  Drinking orange juice (500 mL/d) increases plasma concentrations of vitamin C and reduces concentrations of 8-epi-PGF(2 alpha) in humans. These effects were significantly more pronounced in smokers.
authors.affiliation: Nutrition and Neurocognitive Laboratory, Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA.
authors.forename: Concepción
authors.initials: C
authors.lastname: Sánchez-Moreno
authors.forename: M Pilar
authors.initials: MP
authors.lastname: Cano
authors.forename: Begoña
authors.initials: B
authors.lastname: de Ancos
authors.forename: Lucía
authors.initials: L
authors.lastname: Plaza
authors.forename: Begoña
authors.initials: B
authors.lastname: Olmedilla
authors.forename: Fernando
authors.initials: F
authors.lastname: Granado
authors.forename: Antonio
authors.initials: A
authors.lastname: Martín
mesh_terms: D000328:Adult; D000975:Antioxidants; D001205:Ascorbic Acid / Q000097:blood*; D001628:Beverages; D001682:Biological Availability; D015415:Biomarkers / Q000097:blood; D032084:Citrus sinensis; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D018384:Oxidative Stress; D012907:Smoking / Q000097:blood; D013997:Time Factors
chemical_list: D000975:Antioxidants; D015415:Biomarkers; C075750:8-epi-prostaglandin F2alpha; D015237:Dinoprost; D001205:Ascorbic Acid