Dr. Oscar Franco and colleagues at the University of Cambridge carried out a large scale review of the existing evidence to evaluate the effects of eating chocolate on cardiovascular events like heart attack and stroke.
They analyzed the results of seven studies, involving more than 100,000 participants with and without existing heart disease. For each study, they compared the group with the highest chocolate consumption against the group with the lowest consumption. Differences in study design and quality were also taken into account to minimize bias.
Five studies reported a beneficial link between higher levels of chocolate consumption and the risk of cardiovascular events and they found that the "highest levels of chocolate consumption were associated with a 37 percent reduction in cardiovascular disease and a 29 percent reduction in stroke compared with lowest levels."
However, there was no significant reduction was found in relation to heart failure.
The studies did not differentiate between dark or milk chocolate and included consumption of chocolate bars, drinks, biscuits and desserts.
The researchers said the findings need to be interpreted with caution, in particular because commercially available chocolate is very calorific -- around 500 calories for every 100 grams, or 33.5 ounces -- and eating too much of it could in itself lead to weight gain, risk of diabetes and heart disease.
However, the researchers concluded, given the health benefits of eating chocolate, initiatives to reduce the current fat and sugar content in most chocolate products should be explored.
The findings were presented at the European Society of Cardiology Congress in Paris.