Effect of a wild blueberry (Vaccinium angustifolium) drink intervention on markers of oxidative stress, inflammation and endothelial function in humans with cardiovascular risk factors

Abstract

Wild blueberries (WB) (Vaccinium angustifolium) are rich sources of polyphenols, such as flavonols, phenolic acids and anthocyanins (ACNs), reported to decrease the risk of cardiovascular and degenerative diseases. This study investigated the effect of regular consumption of a WB or a placebo (PL) drink on markers of oxidative stress, inflammation and endothelial function in subjects with risk factors for cardiovascular disease. Eighteen male volunteers (ages 47.8 ± 9.7 years; body mass index 24.8 ± 2.6 kg/m²) received according to a cross-over design, a WB (25 g freeze-dried powder, providing 375 mg of ACNs) or a PL drink for 6 weeks, spaced by a 6-week wash-out. Endogenous and oxidatively induced DNA damage in blood mononuclear cells, serum interleukin levels, reactive hyperemia index, nitric oxide, soluble vascular adhesion molecule concentration and other variables were analyzed. Wild blueberry drink intake significantly reduced the levels of endogenously oxidized DNA bases (from 12.5 ± 5.6 % to 9.6 ± 3.5 %, p ≤ 0.01) and the levels of H₂O₂-induced DNA damage (from 45.8 ± 7.9 % to 37.2 ± 9.1 %, p ≤ 0.01), while no effect was found after the PL drink. No significant differences were detected for markers of endothelial function and the other variables under study. In conclusion, the consumption of the WB drink for 6 weeks significantly reduced the levels of oxidized DNA bases and increased the resistance to oxidatively induced DNA damage. Future studies should address in greater detail the role of WB in endothelial function. This study was registered at www.isrctn.org as ISRCTN47732406.