Erectile dysfunction can be one of the most distressing conditions a man experiences. But a new study suggests eating more foods rich in flavonoids - such as blueberries, strawberries, blackberries and citrus fruits - could reduce the risk of erectile dysfunction for middle-aged men by more than a fifth.

It is estimated that around 30 million men in the US have erectile dysfunction - the inability to get or keep an erection firm enough to engage in sexual intercourse. Men over the age of 60 are at greatest risk for erectile dysfunction, though it occurs in around 12% of men under this age.

Previous research has shown that regular exercise may lower men's risk for erectile dysfunction. However, in this latest study, Prof. Cassidy and her team suggest that eating more flavonoid-rich foods is as beneficial for erectile dysfunction as walking briskly for up to 5 hours weekly.

Exercise and flavonoid-rich diet can reduce erectile dysfunction risk by 21%. The researchers analyzed population-based data of more than 50,000 middle-aged men. Information was collected on the men's ability to get and maintain an erection firm enough for intercourse, and dietary data was collected every 4 years from 1986.

High blood pressure, diabetes, chronic kidney disease and heart and blood vessel disease are just some conditions that can trigger erectile dysfunction. Psychological problems, such as anxiety and depression, can also contribute to erectile dysfunction. Around 30% of men aged 70 and older experience erectile dysfunction.