Is Chocolate good for your heart? It depends.

Chocolate may be good for the heart but cardiologists are not giving you a license to indulge.

New research presented at Europe's biggest medical meeting Monday suggested chocolate consumption might be associated with a one third reduction in the risk of developing heart disease.

Just why there should be such a link was unclear, the European Society of Cardiology congress was told.

There has been a string of scientific studies in recent years showing a potential health benefit from eating chocolate. Dark chocolate, in particular, contains compounds called flavanols thought to be good for the blood system.

In an attempt to paint a clearer picture, Oscar Franco and colleagues from the University of Cambridge pooled results from seven studies involving 100,000 people.

Five of the studies showed a beneficial link between eating chocolate and cardiovascular health, while two did not.

Overall, the findings showed 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 the lowest levels.

Franco said there were limitations with the pooled analysis, which did not differentiate between dark and milk chocolate, and more research was needed to test whether chocolate actually caused better health outcomes or if it was due to some other confounding factor.

"Evidence does suggest chocolate might have some heart health benefit but we need to find out why that might be," said Victoria Taylor, of the British Heart Foundation, who was not involved in the research.

"If you want to reduce your heart disease risk, there are much better places to start than at the bottom of a box of chocolates."

Franco, whose findings were also published online in the British Medical Journal, said while it seemed chocolate had heart benefits, these could easily be outweighed by the unhealthy nature of much confectionery.

"The high sugar and fat content of commercially available chocolate should be considered, and initiatives to reduce it might permit an improved exposure to the beneficial effect of chocolate," the research team wrote.