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

Faisel Khan, Sumantra Ray, Angela M Craigie, Gwen Kennedy, Alexander Hill, Karen L Barton, Jane Broughton, Jill JF Belch

    Research output: Contribution to journalArticle

    53 Citations (Scopus)

    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 250 ml 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±21.0 µmol/L, P<0.001) and high (34.6±20.4 to 73.8±23.3 µmol/L, P<0.001) blackcurrant juice drink groups compared with the placebo group (38.1±21.0 to 29.0±17.6 µmol/L). F2-isoprostane concentrations were significantly lower in the high blackcurrant juice drink group (225±64 pg/ml) compared with the low blackcurrant juice drink (257±69 pg/ml, P=0.002) and placebo group (254±59 pg/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.
    Original languageEnglish
    Pages (from-to)232-237
    Number of pages6
    JournalFree Radical Biology and Medicine
    Volume72
    Early online date15 Apr 2014
    DOIs
    Publication statusPublished - 31 Jul 2014

    Keywords

    • Antioxidant
    • Vitamin C
    • Oxidative stress
    • Endothelial function
    • Blackcurrant juice`
    • Free radicals

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