It has long been a belief that the Mediterranean diet - rich in vegetables and fruit and low in saturated fats - will improve health generally, but scientists have now provided powerful evidence that it can could help humans live longer.

A study of 74,607 men and women aged over 60 proved that strictly following the diet can actually extend life by up to one year.

The pan-European study, which was led by University of Athens Medical School, is published in the latest British Medical Journal.

Researchers collected information on areas including diet, lifestyle, medical history, smoking and physical activity.

Participants were scored on their adherence to a Mediterranean diet, and researchers found that a higher dietary score was linked to a lower overall death rate.

A two-point increase in the score was in fact linked to an eight per cent reduction in mortality. A three-point increase saw mortality drop by 11 per cent and a four-point increase was associated with a 14 per cent drop.

A healthy man of 60 who sticks closely to a Mediterranean diet can therefore expect to live around one year longer than a man of the same age who does not eat such a diet, according to the findings.

The link was strongest in Greece and Spain where people follow a genuinely Mediterranean diet.

Not surprisingly, the UK was found to be lagging behind. Rebecca Foster, a nutrition scientist at the British Nutrition Foundation, said: "Although dietary surveys indicate that we are eating fewer calories, less total fat and we are beginning to see a reduction in salt intake, we are still not meeting the UK dietary guidelines, which are in line with the characteristics of the Mediterranean diet.

"In particular, the Mediterranean countries such as Spain and Greece eat a lot more fruit and vegetables and have a lower intake of saturated fat."

She added that the findings could in part be down to genetic factors, rather than simply diet alone.

Belinda Linden, of the British Heart Foundation, said: "Dietary studies are often difficult to carry out as it is hard to define which constituent of the diet provides the most benefit.

"But that should not put us off trying - it is vital that large and in-depth dietary studies such as these are carried out to further our understanding of the way different diets affect our health.

"Importantly, however, the diet is only one part of lifestyle change needed to reduce coronary heart disease and we must also aim to increase our activity levels, control our weight and stop smoking."