Scientists have produced more compelling evidence that cocoa is good for your heart.
Eating cocoa seems to have pros and cons
Dutch scientists found elderly men who consumed cocoa had lower blood pressure levels, and were less likely to die from cardiovascular problems.
They say cocoa contains ingredients which may keep the circulatory system healthy in different ways.
But UK experts warned the Archives of Internal Medicine study was not an excuse to gorge on cocoa products.
Cocoa has been linked to cardiovascular health benefits since at least the 18th century, but researchers are just beginning to collect scientific evidence for these claims.
The Dutch team, from the National Institute for Public Health and the Environment in Bilthoven, focused on 470 men aged 65 to 84 years.
The men underwent physical examinations and were interviewed about their dietary intake when they enrolled in the study in 1985 and at follow-up visits in 1990 and 1995.
Over the next 15 years, men who consumed cocoa regularly had significantly lower blood pressure than those who did not.
Over the course of the study, 314 men died, 152 due to cardiovascular diseases.
Men in the group with the highest cocoa consumption were half as likely as the others to die from cardiovascular disease.
Their risk remained lower even when other factors, such as weight, smoking habits, physical activity levels, calorie intake and alcohol consumption were taken into account.
The men who consumed more cocoa were also less likely to die of any cause.
However, the researchers said there was no evidence of a direct link between low blood pressure and a lower risk of fatal cardiovascular disease.
Cocoa contains chemicals called flavan-3-oils, which have been linked to lower blood pressure and improved function of the cells lining the blood vessels.
But the Dutch team believes the reduced risk of cardiovascular disease may be down to the fact that cocoa is also a rich source of antioxidants.
These substances are able to limit the tissue damage caused by highly reactive chemicals called free radicals, which are released by the body's energy-producing processes.
Cathy Ross, medical spokesperson for the British Heart Foundation, said: "There is some evidence that when eaten in small quantities, dark chocolate might have some beneficial effects on blood vessels and lowering blood pressure, but as yet no study has investigated the long-terms clinical effects.
"This small study from Holland reinforces the fact that more still needs to be done to determine how eating cocoa affects coronary heart disease in the long term."
She stressed that consuming cocoa was more often part of the problem than the solution.
"Cocoa is rarely tolerable in large amounts in its raw state and therefore to consume the suggested therapeutic amount you would have to have 100g of dark chocolate per day.
"This would mean an average intake of 500 calories per 100g and an average 30% of fat. Eating less did not produce the same effect.
"We are certainly not suggesting people never eat chocolate - everyone can enjoy a treat from time to time.
"But there are much better ways of improving your heart health."