The study, published in an issue of The Lancet, looked at 1,000 patients with a history of problems associated with coronary artery disease (CAD) such as angina, heart attack and diabetes.

Researchers found that those who were given the Indo-Mediterranean diet, rich in alpha-linolenic acid, had fewer cardiac events after two years' follow-up.

The group also had half the number of sudden cardiac deaths and half the proportion of non-fatal heart attacks.

Researchers R B Singh, from Moradabad, India, and Elliot Berry, from Hebrew University Hadassah Medical school, Jerusalem, Israel, and their colleagues split the random group of 1,000 in half.

One group of 499 patients were instructed to eat a diet rich in whole grains, fruits, vegetables, walnuts and almonds. The control group of 501 patients consumed a more conventional local diet, similar to step 1 National Cholesterol Education Program (NCEP) prudent diet.

The average daily intake of alpha-linolenic acid was doubled in the diet of the patients following the Indo-Mediterranean programme.

This group had 39 cardiac events during the two-year study.

This figure compared with 76 in the control group.

CAD is a major public health problem among south Asian people, but is not explained by usual factors such as high blood pressure or high cholesterol.

Those of south Asian origin who live in developed countries have an increased mortality rate and are more susceptible to CAD compared with the indigenous population.

The American Heart Association (AHA) has highlighted the health benefits of a Mediterranean-style diet, rich in alpha-linolenic acid.