New York, Jul 29 (IANS): People who eat a diet that includes at least half a serving per day of foods high in flavonoids like strawberries, oranges, peppers and apples may have a 20 per cent lower risk of cognitive decline, according to a study.

Flavonoids are naturally occurring compounds found in plants and are considered powerful antioxidants. It is thought that having too few antioxidants may play a role in cognitive decline as you age.

The study, published in the journal Neurology, showed that flavones -- found in some spices and yellow or orange fruits and vegetables -- had the strongest protective qualities, and were associated with a 38 per cent reduction in risk of cognitive decline, which is the equivalent of being three to four years younger in age.

Peppers have about 5 mg of flavones per 100 gram serving. Anthocyanins, found in blueberries, blackberries and cherries, were associated with a 24 per cent reduced risk of cognitive decline. Blueberries have about 164 mg of anthocyanins per 100 gram serving.

"A colourful diet rich in flavonoids -- and specifically flavones and anthocyanins -- seems to be a good bet for promoting long-term brain health. Our results are exciting because they show that making simple changes to your diet could help prevent cognitive decline,"said Walter Willett, from Harvard University in Boston, US.

"The people in our study who did the best over time ate an average of at least half a serving per day of foods like orange juice, oranges, peppers, celery, grapefruits, grapefruit juice, apples and pears," Willett added.

The study looked at 49,493 women with an average age of 48 and 27,842 men with an average age of 51 at the start of the study.

Over 20 years of follow up, people completed several questionnaires about how often they ate various foods. Their intake of different types of flavonoids was calculated by multiplying the flavonoid content of each food by its frequency.