A few squares of dark chocolate every day may cut the risk of serious heart disease, a new study by a team from University Hospital in Zurich has shown.
But chocolate lovers should be aware that only small daily quantities of high cocoa dark chocolate score health points. Milk and white chocolate don't offer much more than calories.
"Only a small daily treat of dark chocolate may substantially increase the amount of antioxidant intake and beneficially affect vascular health," the report's authors said.
Researchers studied 20 male smokers, who are at greater risk of hardening arteries characteristic of coronary heart disease, to see the effects of dark and white chocolate on arterial blood flow.
Smoking compromises the activity of the cells, which line the artery walls, and platelets, which are involved in blood clot formation.
The group, who were asked to abstain from eating foods rich in antioxidants for 24 hours, were given 40 grams of chocolate to eat.
Improved blood flow
After two hours, ultrasound scans revealed that dark chocolate - made up of 74 per cent cocoa solids - significantly improved the smoothness of arterial flow, an effect which lasted eight hours.
When the experiment was repeated with white chocolate - with only four-per-cent cocoa - there was no effect, the study published in Heart medical journal said.
The researchers, who said further studies were needed, suggested that the possible benefits arose from the antioxidants in dark chocolate.
Dark chocolate contains more antioxidants per gram than other food and drink with the same properties, such as red wine, tea and berry fruits.
Previous studies have lauded the benefits of dark chocolate to health but the caveat remains that while a little chocolate may be good for you, a lot of chocolate - with its high calorie and fat content - is not.
swissinfo with agencies
Dark chocolate is rich in cocoa, a bitter extract from cacao beans, and relatively low in fats and sugars.
Cocoa contains fibre and useful minerals and vitamins, as well as flavanoids. Similar to chemicals abundant in red wine, purple grape juice and some teas, fruits and vegetables, these compounds impart the bitter taste.
Studies, including the latest one from Zurich, suggest that flavanoids have positive effects on blood vessels and act as antioxidants to prevent harmful changes in the body.