The lives of 20,000 Britons a year would be saved if everyone ate a Mediterranean diet, it is claimed.
In the first study of its kind, doctors evaluated the effects of an olive oil, fish and nut-rich diet on the health of ordinary people in England.
It revealed that one in eight deaths from heart attacks, strokes and other types of cardiovascular disease could be prevented if everyone followed a Mediterranean diet.
The Cambridge University researchers said this makes the eating plan as good for the heart as exercise.
Cardiovascular disease is behind more than one in four deaths, killing 155,000 Britons a year.
Study author Dr Nita Forouhi said: ‘A higher level of adherence to the Mediterranean diet could have a significant impact on lowering the cardiovascular disease burden in the UK.’
Dr Forouhi crunched data on almost 24,000 men and women aged 40-plus from Norfolk whose lives were tracked for up to 20 years.
All filled in a detailed dietary questionnaire, underwent various health checks and recorded whether they smoked and how much they exercised.
None suffered heart problems at the start of the study but, by its end, 7,606 of them had suffered a heart attack, stroke or other problem, and 1,714 had died as a result.
Those who ate the most Mediterranean-like diet had the fewest heart problems, the journal BMC Medicine reports.
The traditional diet of Greece and southern Italy involves eating meals rich in fruit, vegetables, cereals, nuts, seeds and olive oil.
Dairy products, fish, poultry and red wine are also encouraged, but red and processed meat should be eaten in moderation.
Numerous studies done in the Mediterranean have shown it to benefit health, but those done in other countries have provided conflicting results.
And no proper research has been carried out in the UK, despite health authorities promoting the diet.
Dr Forouhi said: ‘We estimate that 3.9 per cent of all new cardiovascular disease cases, or 12.5 per cent of cardiovascular deaths in our study population, could potentially be avoided if this population increased their adherence to the Mediterranean diet.’
UK-wide, this would equate to almost 20,000 lives being saved annually.
The change could also provide numerous other benefits, with a Mediterranean diet warding off ills from cancer to diabetes and Alzheimer’s disease.
The Cambridge University researchers said this makes the eating plan as good for the heart as exercise
Dr Forouhi added: ‘Encouraging greater adoption of the Mediterranean diet looks like a promising component of a wider strategy to help prevent cardiovascular disease, including other important factors such as not smoking and maintaining a healthy weight, blood cholesterol and blood pressure.’
Professor Ian Johnson, of the Institute of Food Research in Norwich, said: ‘This is a careful and rigorous study showing a relatively small but potentially important association between higher adherence to a Mediterranean-style diet and reduced risk of heart disease and death from heart disease.’
The British Heart Foundation welcomed the research but cautioned that there is more to good health than just eating well.
Tracy Parker, a dietician at the charity, said: ‘The researchers found that those with high adherence to the diet were less likely to be smokers and more likely to be physically active – both important independent factors in reducing a person’s risk of cardiovascular disease.’