Acute effects of flavonoid-rich blueberry on cognitive and vascular function in healthy older adults

BACKGROUND: Consumption of flavonoids, natural compounds found in foods such as berries and cocoa, have been shown to be beneficial for cognitive function. However, less is known about potential mechanisms and acute benefits for the older population. OBJECTIVE: To determine whether acute intake of flavonoid-rich blueberry could have beneficial effects on cognitive function in a sample of healthy older adults and identify possible mechanisms. METHODS: A cross-over randomised controlled trial (RCT) was conducted (N = 18) with volunteers receiving a flavonoid-rich blueberry beverage (579mg of antho- and pro-cyanidins) on one visit and a sugar-matched control on another. Cognitive function was measured at baseline, 2 and 5 hours post consumption of the intervention and blood pressure (BP), arterial stiffness and plasma brain-derived neurotrophic factor (BDNF) concentration at baseline and an hour post-intervention. RESULTS: Whilst there was no significant effect of the intervention on global cognitive function, performance was significantly different at 2 compared to 5 hours following the control beverage (p <  0.05), with a decline in performance relative to baseline at 2 hours, whereas cognitive function improved following the blueberry beverage at both post intervention time points. There was also a trend towards the blueberry beverage attenuating the increase in systolic BP evident following the control drink (p = 0.08). Finally, there was a decrease in plasma concentration of BDNF post consumption of the control drink which was attenuated following the blueberry beverage, although not significantly (p >  0.05). CONCLUSIONS: A single dose of flavonoid-rich blueberry could have a potentially protective effect on cognitive function in healthy older adults, possibly due to improved cerebrovascular function and positive interactions with cell signalling pathways involved in cognitive processes.