The findings confirm results of existing studies that generally agree on a potential beneficial link between chocolate consumption and heart health. However, the authors stress that further studies are now needed to test whether chocolate actually causes this reduction or if it can be explained by some other unmeasured (confounding) factor.
The World Health Organisation predicts that by 2030, nearly 23.6 million people will die from heart disease. However, lifestyle and diet are key factors in preventing heart disease, says the paper.
A number of recent studies have shown that eating chocolate has a positive influence on human health due to its antioxidant and anti-inflammatory properties. This includes reducing blood pressure and improving insulin sensitivity (a stage in the development of diabetes).
However, the evidence about how eating chocolate affects your heart still remains unclear. So, Dr Oscar Franco and colleagues from 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 analysed the results of seven studies, involving over 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 minimise 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% reduction in cardiovascular disease and a 29% reduction in stroke compared with lowest levels." 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 authors say the findings need to be interpreted with caution, in particular because commercially available chocolate is very calorific (around 500 calories for every 100 grams) and eating too much of it could in itself lead to weight gain, risk of diabetes and heart disease.
However, they conclude that, given the health benefits of eating chocolate, initiatives to reduce the current fat and sugar content in most chocolate products should be explored.