Enhanced task-related brain activation and resting perfusion in healthy older adults after chronic blueberry supplementation

Abstract

Blueberries are rich in flavonoids, which possess antioxidant and anti-inflammatory properties. High flavonoid intakes attenuate age-related cognitive decline, but data from human intervention studies are sparse. We investigated whether 12 weeks of blueberry concentrate supplementation improved brain perfusion, task-related activation, and cognitive function in healthy older adults. Participants were randomised to consume either 30 mL blueberry concentrate providing 387 mg anthocyanidins (5 female, 7 male; age 67.5 ± 3.0 y; body mass index, 25.9 ± 3.3 kg·m−2) or isoenergetic placebo (8 female, 6 male; age 69.0 ± 3.3 y; body mass index, 27.1 ± 4.0 kg·m−2). Pre- and postsupplementation, participants undertook a battery of cognitive function tests and a numerical Stroop test within a 1.5T magnetic resonance imaging scanner while functional magnetic resonance images were continuously acquired. Quantitative resting brain perfusion was determined using an arterial spin labelling technique, and blood biomarkers of inflammation and oxidative stress were measured. Significant increases in brain activity were observed in response to blueberry supplementation relative to the placebo group within Brodmann areas 4/6/10/21/40/44/45, precuneus, anterior cingulate, and insula/thalamus (p < 0.001) as well as significant improvements in grey matter perfusion in the parietal (5.0 ± 1.8 vs –2.9 ± 2.4%, p = 0.013) and occipital (8.0 ± 2.6 vs –0.7 ± 3.2%, p = 0.031) lobes. There was also evidence suggesting improvement in working memory (2-back test) after blueberry versus placebo supplementation (p = 0.05). Supplementation with an anthocyanin-rich blueberry concentrate improved brain perfusion and activation in brain areas associated with cognitive function in healthy older adults.