title: A randomised trial to investigate the effects of acute consumption of a blackcurrant juice drink on markers of vascular reactivity and bioavailability of anthocyanins in human subjects.
abstract: OBJECTIVE
  To study the bioavailability of anthocyanins and the effects of a 20% blackcurrant juice drink on vascular reactivity, plasma antioxidant status and other cardiovascular disease risk markers.
  
  
  METHODS
  The study was a randomised, cross-over, double-blind, placebo-controlled acute meal study. Twenty healthy volunteers (11 females and 9 males) were recruited, and all subjects completed the study. Fasted volunteers consumed a 20% blackcurrant juice drink (250 ml) or a control drink following a low-flavonoid diet for the previous 72 h. Vascular reactivity was assessed at baseline and 120 min after juice consumption by laser Doppler imaging (LDI). Plasma and urine samples were collected periodically over an 8-h period for analysis, with a final urine sample collected at 24 h. The cross-over was performed after a 4-week washout.
  
  
  RESULTS
  There were no significant effects of the 20% blackcurrant juice drink on acute measures of vascular reactivity, biomarkers of endothelial function or lipid risk factors. Consumption of the test juice caused increases in plasma vitamin C (P=0.006), and urinary anthocyanins (P<0.001). Delphinidin-3-rutinoside and cyanidin-3-rutinoside were the main anthocyanins excreted in urine with delphinidin-3-glucoside also detected. The yield of anthocyanins in urine was 0.021±0.003% of the dietary intake of delphinidin glycosides and 0.009±0.002% of the dietary intake of cyanidin glycosides.
  
  
  CONCLUSIONS
  The juice consumption did not have a significant effect on vascular reactivity. Anthocyanins were present at low concentrations in the urine, and microbial metabolites of flavonoids were detected in plasma after juice consumption.
authors.affiliation: Hugh Sinclair Unit of Human Nutrition and Institute for Cardiovascular and Metabolic Research, Department of Food and Nutritional Sciences, University of Reading, Whiteknights, Reading, Berkshire, UK.
authors.forename: Y
authors.initials: Y
authors.lastname: Jin
authors.forename: D
authors.initials: D
authors.lastname: Alimbetov
authors.forename: T
authors.initials: T
authors.lastname: George
authors.forename: M H
authors.initials: MH
authors.lastname: Gordon
authors.forename: J A
authors.initials: JA
authors.lastname: Lovegrove
mesh_terms: D000328:Adult; D000872:Anthocyanins / Q000032:analysis / Q000378:metabolism* / Q000627:therapeutic use / Q000652:urine; D000975:Antioxidants / Q000032:analysis; D001628:Beverages / Q000032:analysis; D001682:Biological Availability; D015415:Biomarkers / Q000097:blood; D001808:Blood Vessels / Q000187:drug effects / Q000502:physiology*; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000517:prevention & control; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D005638:Fruit / Q000737:chemistry*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000097:blood; D008297:Male; D008875:Middle Aged; D009753:Nutritive Value; D010636:Phenols / Q000097:blood / Q000652:urine; D031965:Ribes / Q000737:chemistry*; D012307:Risk Factors; D006113:United Kingdom / Q000453:epidemiology; D019010:Vascular Cell Adhesion Molecule-1 / Q000097:blood
chemical_list: D000872:Anthocyanins; D000975:Antioxidants; D015415:Biomarkers; D010636:Phenols; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1