IT is the ultimate comfort food, which is known to produce the same brain chemicals that are released when someone is falling in love.

But now scientists have shown that chocolate need no longer be a guilty pleasure after finding that eating up to two small bars a day appears to protect against heart disease and stroke.

Though eating dark chocolate has long been thought to have health benefits, a study at the University of Aberdeen has found that milk chocolate may also provide valuable nutrients. Researchers who examined the eating habits of 21,000 people over 12 years found that eating up to 3.5oz (100g) of chocolate a day lowered the risk of dying from heart disease by 25 per cent. The chance of suffering a stroke also fell by 23 per cent.

Prof Phyo Myint, chairman of old age medicine at Aberdeen University, said: “Cumulative evidence suggests that higher chocolate intake is associated with a lower risk of future cardiovascular events. This may indicate that not only flavonoids, but also other compounds, possibly related to milk constituents, such as calcium and fatty acids, may provide an explanation for the observed association.”

The researchers also carried out a review, involving almost 158,000 people, of the available published evidence on the links between chocolate and cardiovascular disease.

In each of the relevant studies, they found a significantly lower risk of stroke and heart disease associated with regular chocolate consumption.

Curiously, those who ate the most chocolate were slimmer, exercised more often and had lower blood pressure.

The researchers suggest that the findings could be partially skewed by misreporting of food intake or the fact that people with a higher risk of heart disease eat less chocolate than those who are healthier.

Commenting on the study, Prof Naveed Sattar, of the University of Glasgow, said: “It may be that some folk are, perhaps substantially, under-reporting how much chocolate they eat, since they really do not wish to tell the truth, because they know they should try to avoid high-density calories like chocolate.

“I would not be rushing out to buy chocolate for a treat. If peckish, a piece or two of fruit is far better and comes from nature itself.”

Health experts said the study added to growing evidence that chocolate could be beneficial to health but warned against over indulging. Dr Tim Chico, reader in cardiovascular medicine and consultant cardiologist at the University of Sheffield, said: “These studies taken together suggest that there might be some health benefits from eating chocolate. However, it is also clear that chocolate has the potential to increase weight, which is unequivocally bad for cardiovascular health. The message I take is that if you are a healthy weight, then eating chocolate (in moderation) does not detectably increase risk of heart disease and may even have some benefit.”

Aedin Cassidy, professor of nutrition at the University of East Anglia, added: “We need long-term trials to further understand the importance of chocolate for heart health.”

The findings were published in the BMJ journal Heart.