Eating dark chocolate can prevent heart disease

Unfortunately, it appears that an ounce a day is all we can justify on medical grounds.

After reviewing previous studies into chocolate and heart disease, one expert has calculated the optimum daily dose.

Professor Roger Corder says that an ounce, or 25g - around two or three squares - is best.

The type of chocolate is also crucial as some contain more of the key ingredient, flavonoids.

These compounds, which occur naturally in cocoa beans, cut the risk of dangerous blood clots and relax blood vessels, stimulating the flow of blood around the body.

Flavonoids tend to be higher in dark chocolate, as it has a higher cocoa content. But Professor Corder, of Queen Mary, University of London, says some processing techniques damage the compounds more than others.

He said levels can even vary greatly between batches of the same brand, and called for manufacturers to include flavonoid content on labels.

He does however, have a few suggestions: "Lindt 85 per cent is what I have been eating. Their 75 per cent Ecuadorian chocolate is also very good."

Speaking at the British Association Festival of Science in York, the researcher said: "Chocolate should be part of a balanced diet. It can't be your fruit and vegetable component of a chips and pizza diet."

Professor Corder based his findings on years of research, including studies of tribes in central America whose diet is exceptionally rich in cocoa.

Dark chocolate may also stave off age-related macular degeneration, the most common cause of blindness in the elderly, and dementia.