Chocoholics are being warned to be sceptical about claims that chocolate is good for the heart.

Scientists sponsored by a confectionery maker say new research suggests that chocolate thins the blood and may help prevent blood clots.

Advising people to eat chocolate regularly for their hearts' sake is a reckless message that people should ignore

British Heart Foundation

Eating chocolate as part of a balanced diet could help maintain a healthy heart and circulation, they propose.

But the British Heart Foundation told BBC News Online that the claims were reckless and people would get more nutrients from eating fruit and vegetables.

Natural compounds in cocoa called flavonoids are believed to be responsible for the reported positive benefits of chocolate.

'Positive effects'

c, Professor of Nutrition and Internal Medicine at the University of California, US, told the British Association Festival of Science in Glasgow: "We are finding increasing evidence to suggest that eating chocolate rich in flavonoids regularly, and as part of a balanced diet, can have positive cardiovascular effects, and may even contribute to a lower risk of blood clots."

The conclusion is based on a small clinical trial of 24 volunteers who ate 25 grams of chocolate a day - equivalent to a small bar.

Preliminary trial results, which have yet to appear in a scientific journal, found that eating chocolate appeared to delay the onset of blood clotting.

Professor Keen, whose work is sponsored by the chocolate maker Mars, said the results led him to believe that chocolate may contribute to a healthy, well-balanced diet.

'Reckless' message

But the British Heart Foundation (BHF) dismissed the new research.

Belinda Linden, Head of Medical Information at the BHF, said: "Advising people to eat chocolate regularly for their hearts' sake is a reckless message that people should ignore.

Chocolate: good or bad?

Contains flavonoids which may be good for the heart Increases antioxidant activity in the blood, in a similar way to red wine May relax blood vessels High in saturated fats and sugar May contribute to obesity, high cholesterol and coronary heart disease

"A little bit of dark chocolate enjoyed as an occasional treat is fine, but the BHF in no way endorses regular chocolate snacking to protect our hearts.

"Yes, chocolate contains flavonoids. However, most chocolate bars contain high levels of saturated fats and sugar that contribute to high cholesterol levels, obesity and coronary heart disease.

"Fruit and vegetables contain much higher levels of flavonoids, plus many other beneficial nutrients - without the fat content.

"So the message is, enjoy a little chocolate in moderation, but ensure you eat five portions of fruit and vegetables daily to get all the flavonoids you need without the added fat."