Daily consumption of dark chocolate can reduce cardiovascular（心血管的） events, such as heart attacks and strokes, in people with metabolic（新陈代谢的） syndrome (a cluster of factors that increases the risk of developing heart disease and diabetes), finds a study published in the British Medical Journal. Cardiovascular disease is the leading cause of death worldwide. Dark chocolate (containing at least 60% cocoa solids) is rich in flavonoids（黄酮类） -- known to have heart protecting effects -- but this has only been examined in short term studies.

So a team of researchers from Melbourne, Australia used a mathematical model to predict the long-term health effects and cost effectiveness of daily dark chocolate consumption in 2,013 people already at high risk of heart disease.

All participants had high blood pressure and met the criteria for metabolic syndrome, but had no history of heart disease or diabetes and were not on blood pressure lowering therapy.

With 100% compliance (best case scenario), the researchers show that daily dark chocolate consumption could potentially avert 70 non-fatal and 15 fatal cardiovascular events per 10,000 people treated over 10 years.

Even when compliance levels were reduced to 80%, the number of non-fatal and fatal events potentially averted was 55 and 10 per 10,000 people treated over 10 years, and could still be considered an effective intervention strategy.

The model also suggested that $A40 (£25; €31; $42) could be cost effectively spent per person per year on dark chocolate prevention strategies and could be used for advertising, educational campaigns, or subsidizing dark chocolate in this high risk population, they add.

The authors stress that only non-fatal stroke and non-fatal heart attack were assessed in their analysis, and that the potential effects on other cardiovascular events, such as heart failure, are yet to be tested.

Also important, they say, is that these protective effects have only been shown for dark chocolate (at least 60-70% cocoa), rather than for milk or white chocolate, probably due to the higher levels of flavonoids found in dark chocolate.

Nevertheless, they conclude that the blood pressure and cholesterol lowering effects of plain dark chocolate "could represent an effective and cost effective strategy for people with metabolic syndrome (and no diabetes)."