Role of fruit and vegetables in sustaining healthy cognitive function: evidence and issues

Modifiable lifestyle factors, such as improved nutrition, are crucial in maintaining cognitive health in older age. Fruit and vegetables represent healthy and sustainable sources of nutrients with the potential to prevent age-related cognitive decline. The aim of this review is to synthesise the available evidence, from epidemiological and randomised controlled trials (RCTs), regarding the role of fruit and vegetables in sustaining healthy cognitive function. Epidemiological studies of combined fruit and vegetable intake suggest that increased consumption may sustain cognition in later life. The evidence appears to be stronger for an association between vegetables and cognition, particularly for green leafy and cruciferous vegetables. Specific benefits shown for berries, citrus fruits, avocado, and nuts suggest fruit is worthy of further investigation in relation to cognition. Data from RCTs indicates benefits to differing aspects of cognition following citrus and berry fruits, cocoa, and peanuts, but the data is limited and there are a lack of studies exploring effects of vegetables. There is growing evidence for an association between fruit and vegetable intake and cognitive function, but this is not always consistent and the data from RCTs is limited. Issues in previous research are highlighted, such as strict exclusion criteria, absence of baseline nutritional status data, and lack of consideration of individual differences, which may explain the weaker findings from RCTs. Inclusion of those most at risk for cognitive decline is recommended in future nutrition and cognition research.