According to a research, olive oil could be the best chance for men of maintaining a sex life well into old age.

Just nine tablespoons of the oil each week, along with plenty of vegetables, fruit, fish and beans, cuts the risk of erectile dysfunction by 40 per cent.

The study, presented at the European Society of Cardiology conference in Munich, suggests a healthy diet in middle age could pave the way for an active drug-free love life well into their late 60s and 70s.

As well as nine tablespoons of olive oil, they found men tended to be protected if their diet also contained about 13 portions of veg a week, six pieces of fruit, three servings of fish and two portions of beans.

The scientists believe this diet helps men maintain a healthy heart and clear blood vessels. The cardiologists also found men who followed this diet had higher testosterone levels because they had lower levels of body fat – which can interfere with hormones.

Study leader Dr Christina Chrysohoou said: "Viagra does not improve something long-term, it can only give some short effect in order to have sexual capacity.

"This is a drug-free solution that allows men to keep their sexual function.”