A colourful diet rich in grapefruits, carrots and sweet potatoes could cut the risk of Alzheimer’s by more than a third, a study suggests.
A 20-year study tracking 77,000 older people found those who ate most yellow and orange fruit and veg were 38% less likely to suffer mental decline.
The protection was equivalent to being three to four years younger.
High intake of blueberries, blackberries and cherries were associated with a 24% reduced risk. An apple or handful of strawberries a day cut the risk 20%.
Authors say compounds called flavonoids are responsible, particularly the flavone and anthocyanin types.
Yellow and orange plant foods are high in flavones. Darker ones such as blueberries are high in anthocyanins.
Lead author Dr Walter Willett, of Harvard University in the US, said: “There is mounting evidence suggesting flavonoids are powerhouses when it comes to preventing your thinking skills from declining as you get older.
“Our results are exciting... they show making simple changes to your diet could help prevent cognitive decline.”
The study is the first to identify flavones and anthocyanins as the most beneficial types of flavonoid.
Parsley, oregano, saffron, dill, fennel, cloves and thyme are also good sources of them. The findings, published in the journal Neurology, are based on 49,493 women and 27,842 men who were tracked for more than two decades.
They were aged 48 and 51 on average respectively at the start.
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Participants completed several diet surveys and mental abilities were self-reported twice, with questions that assessed volunteers’ memory skills.
The technique picks up early problems that would not necessarily be detected in a screening test.
Dr Willett added of the study participants: “The group of highest flavonoid consumers had 20% less risk of self-reported cognitive decline than the people in the lowest group.
“Adding colour to your plate may lower the risk of cognitive decline."
