| Summary: | Flavonoids are naturally occurring bioactive chemicals which are plentiful in a diet high in fruit and vegetables. Animal research has shown reliable effects of a flavonoid-supplemented diet on biochemical, physiological and psychological indices of brain function, particularly in areas of learning and memory (Joseph et al., 2003; Joseph et al., 1999; C. M. Williams et al., 2008). However, there is a lacuna of human intervention studies which supplement the diet with a flavonoid-high source and measure cognitive function. This area of research is important in view of the increasing incidence of Alzheimer's Disease (AD), in the ageing population, as diet is influential in maintaining healthy cognitive function and has the potential to ameliorate cognitive decline (Alzheimer's Society, 2010). Two human intervention studies were conducted using blueberries as the flavonoid- high source. The acute study administered a one-off dose of flavonoids, contained in a flavonoid-high 'Smoothie' style drink, or a matched flavonoid-Iow control drink, and measured mood, memory, executive function and attention, and motor skills before, and 1 and 5 hours after the drinks. Young and older adults were tested with this method. A chronic study employed an 8 week intervention where the older participants consumed either 80 grams of a flavonoid-high fruit or a flavonoid-Iow control fruit on a daily basis. Measures of mood, memory, executive function and attention were taken at baseline, and after 4 and 8 weeks of the intervention. Preliminary findings from the acute study showed a reliable effect of the flavonoid- high drink on a test of executive function and attention five hours after the drink was consumed by the young adults, compared with the control drink. A similar non- significant trend was observed in the older adults. No reliable effects were observed in the chronic intervention. Overall, little evidence of nutritional treatment effects on cognition were shown.
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