title: Lowering of oxidative stress improves endothelial function in healthy subjects with habitually low intake of fruit and vegetables: a randomized controlled trial of antioxidant- and polyphenol-rich blackcurrant juice.
abstract: Inadequate intake of the recommended five-a-day fruit and vegetable portions might contribute to increased cardiovascular disease risk. We assessed the effects of dietary intake of a blackcurrant juice drink, rich in vitamin C and polyphenols, on oxidative stress and vascular function. This was a double-blind, placebo-controlled, parallel group study of 66 healthy adults who habitually consume <2 portions of fruit and vegetables per day. Participants were randomly allocated to consume 250ml of placebo (flavored water) or low or high blackcurrant juice drink four times a day for 6 weeks. Flow-mediated dilation (FMD) and plasma concentrations of F2-isoprostanes and vitamin C were measured. In the high blackcurrant juice drink group FMD increased significantly (5.8±3.1 to 6.9±3.1%, P=0.022) compared with the placebo group (6.0±2.2 to 5.1±2.4%). Plasma vitamin C concentration increased significantly in the low (38.6±17.6 to 49.4±21.0µmol/L, P<0.001) and high (34.6±20.4 to 73.8±23.3µmol/L, P<0.001) blackcurrant juice drink groups compared with the placebo group (38.1±21.0 to 29.0±17.6µmol/L). F2-isoprostane concentrations were significantly lower in the high blackcurrant juice drink group (225±64pg/ml) compared with the low blackcurrant juice drink (257±69pg/ml, P=0.002) and placebo group (254±59pg/ml, P=0.003). At follow-up, changes in plasma vitamin C correlated significantly with changes in FMD (r=0.308, P=0.044). Consumption of blackcurrant juice drink high in vitamin C and polyphenols can decrease oxidative stress and improve vascular health in individuals with habitually low dietary fruit and vegetable intake.
authors.affiliation: Vascular and Inflammatory Diseases Research Unit and, Dundee DD1 9SY, UK. Electronic address: f.khan@dundee.ac.uk.
authors.forename: Faisel
authors.initials: F
authors.lastname: Khan
authors.affiliation: Vascular and Inflammatory Diseases Research Unit and, Dundee DD1 9SY, UK.
authors.forename: Sumantra
authors.initials: S
authors.lastname: Ray
authors.affiliation: Centre for Public Health Nutrition Research, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Craigie
authors.affiliation: Vascular and Inflammatory Diseases Research Unit and, Dundee DD1 9SY, UK.
authors.forename: Gwen
authors.initials: G
authors.lastname: Kennedy
authors.affiliation: Vascular and Inflammatory Diseases Research Unit and, Dundee DD1 9SY, UK.
authors.forename: Alexander
authors.initials: A
authors.lastname: Hill
authors.affiliation: Centre for Public Health Nutrition Research, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK.
authors.forename: Karen L
authors.initials: KL
authors.lastname: Barton
authors.affiliation: GlaxoSmithKline, Brentford, Middlesex TW8 9GS, UK.
authors.forename: Jane
authors.initials: J
authors.lastname: Broughton
authors.affiliation: Vascular and Inflammatory Diseases Research Unit and, Dundee DD1 9SY, UK.
authors.forename: Jill J F
authors.initials: JJ
authors.lastname: Belch
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000097:blood; D001628:Beverages; D004035:Diet Therapy / Q000379:methods*; D004311:Double-Blind Method; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006801:Humans; D028421:Isoprostanes / Q000097:blood; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects*; D059808:Polyphenols / Q000494:pharmacology; D031965:Ribes; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology
chemical_list: D000975:Antioxidants; D028421:Isoprostanes; D059808:Polyphenols; D001205:Ascorbic Acid
keywords: Antioxidant; Blackcurrant juice; Endothelial function; Free radicals; Oxidative stress; Vitamin C