A slice of cherry pie a day may help stave off heart disease, research has found.

The fruit also lowers cholesterol levels and may reduce the risk of diabetes.

The darker the cherry the better, as the health effect comes from the pigment responsible for their red colour.

And sour cherries - used in pies, jams and juices - are more beneficial than the sweet dessert variety.

The researcher team, from the University of Michigan in the U.S., reached their results by adding powdered cherries to the food of a group of rats.

After three months, the rats had significantly lower cholesterol levels than another group who had stayed on their normal diet. The cherry rats also fared better when measured for levels of insulin and other factors linked to metabolic syndrome - a condition which often leads to heart disease or diabetes.

Researcher Dr Steven Bolling said the benefits came from small amounts of cherries, just 1 per cent of the animals’ diet.

Unveiling the results at the annual conference of the American Societies for Experimental Biology, he said the team now plans to start trials on humans. The key to the cherry’s success is anthocyanins, natural compounds which help stop cholesterol clogging up arteries. Sour cherries are especially rich in anthocyanins.

Studies have shown that cherries also offer hope for relieving the pain of arthritis and may help us get a good night’s sleep by regulating our natural cycle.

The fruit has been used in medicine for hundreds of years. Ground-up cherry stones were used to counteract the pain of chest conditions and stomach problems in the 15th and 16th centuries. Eating whole cherries was once thought to ward off kidney stones and herbalists brewed the stalks into a tea to treat bronchitis.

Improved treatments have almost halved the death rate from severe heart attacks across the Western world, a major study showed yesterday.

The research team, co-ordinated by Edinburgh University, analysed 44,372 patients admitted to 113 hospitals in 14 countries.

For patients whose arteries were completely blocked, the death rate had fallen from 8.4 to 4.5 per cent over six years. Deaths in patients with milder heart attacks fell by a smaller margin.

The study, published in the Journal of the American Medical Association, also found that patients suffering from all forms of heart attack were now less likely to be hit by strokes or further attacks.

Journal of the American Medical Association