Eating oil-rich fish can do more to help keep some heart attack victims alive than taking drugs, it has been claimed.

A study of 2,033 male survivors of heart attacks found that deaths were reduced by one-third among those who ate two portions of oil-rich fish a week over a two-year period.

The research was highlighted in a letter to the British Medical Journal written by public health experts Roger Harrison, from Wigan, and Michael Burr, from Cardiff.

Cheap and simple alternative

The authors claim that the fish diet, as well as being a cheap and simple alternative to drugs, has no known side effects. It was also easy to persuade patients to stick to their diet.

"The benefits for survivors of myocardial infarction of eating oil-rich fish far exceed those expected from some pharmacological regimens," the authors write.

"Furthermore, these agents will often be more expensive than dietary advice, have contraindications to their use, and may have clinically important side effects.

"We suggest that if the benefits in the diet and reinfarction trial, or even smaller benefits, had been obtained from a drug then more support would be given to its use."

Fish are rich in omega-3 fatty acids, a form of polyunsaturated fat that lowers blood levels of low-density lipoproteins - compounds that are linked to heart disease.

Consultant physician and former Secretary of the British Hypertension Society Dr Gordon McInnes said fish oil could be used to complement drugs.

"There is a general feeling that fish oil is good in terms of cardiovascular protection.

"But the suggestion that it is better than some drugs is obviously contentious - it would be crazy to say let's forget about these drugs."