Flavonoid-rich foods are associated with a reduced risk of erectile dysfunction, says a new study.

Eating foods rich in certain flavonoids trims down the risk of erectile dysfunction in men, especially in those under 70, reveals a collaborative study from the University of East Anglia (UEA) in UK and Harvard University in the US.

A combination of consuming flavonoid-rich foods with exercise can reduce the risk by 21 percent, the researchers said.

"This is the first study to look at the association between flavonoids and erectile dysfunction, which affects up to half of all middle-aged and older men," said Aedin Cassidy, a professor from UEA.

The research shows that of all the different flavonoids, anthocyanins (found in blueberries, cherries, blackberries, radishes and blackcurrants), flavanones and flavones (found in citrus fruits) were found to offer the greatest benefits.

"The top sources of anthocyanins, flavones and flavanones consumed in the US are strawberries, blueberries, red wine, apples, pears and citrus products," Cassidy said.

Eating a flavonoid-rich diet is as good for erectile function as briskly walking for up to five hours a week, the findings, published in The American Journal of Clinical Nutrition, showed.

More than 50,000 middle-aged men were included in this large population based study.

Dating back to 1986, they were asked about their ability to have and maintain an erection sufficient for intercourse.