But the finding doesn't call for a cocoa binge; for Professor Roger Corder says that eating 'small amounts' of chocolate each day has "considerable potential to improve health and wellbeing".
After reviewing previous studies into chocolate and heart disease, Prof Corder calculated the perfect daily dose to an ounce, or 25g - around two or three squares.
He further says that the type of chocolate is also crucial as some contain more of the key ingredient, flavonoids.
Cocoa flavonoids found in quality dark chocolate have a range of beneficial effects on the blood and circulation system - they cut the risk of dangerous blood clots and relax blood vessels, stimulating the flow of blood around the body.
He said that flavonoid levels can even vary greatly between batches of the same brand, and called for manufacturers to include flavonoid content on labels.
Prof Corder suggested that the best products to buy were those with at least 70 per cent cocoa, as they were the most likely to have high levels of flavonoids.
He added that his research, based on studies of tribes in Central America whose diet is exceptionally rich in cocoa, has confirmed that these boost the elasticity of blood cells, and also cuts down the risk of high blood pressure, blood clots, strokes and heart disease.
"Chocolate should be part of a balanced diet. It can't be your fruit and vegetable component of a chips and pizza diet. Lindt 85 per cent is what I have been eating. Their 75 per cent Ecuadorian chocolate is also very good," the Daily Mail quoted him, as stating at the British Association Festival of Science in York.
Another study in the US has found that dark chocolate may also ward off age-related macular degeneration, the most common cause of blindness in the elderly, and dementia.