Chocolates are often thought to contribute towards an unhealthy diet - but research being carried out in Sweden could change all that.

At the Karolinska Institutet in Stockholm, the eating habits of over 33,000 women aged between 49 and 83 years were analyzed in 1997.

Chocolate consumption was assessed using a self-administered food-frequency questionnaire. Women were asked to indicate how often on average they had consumed chocolate and 95 other foods during the previous year.

In the 10 years after the study 1,549 women who took part in the study had some type of stroke.

When the researchers studied the results more closely they found the occurrences of strokes was significantly higher among the women who consumed no chocolate. They also found that the more chocolate the women ate the less likely they were to have a stroke.

In the group that ate the most chocolate, over 66 grams a week, the risk of stroke was reduced by 20 per cent.

Susanna Larsson is the Associated Professor for Institute for environmental science at Karolinska Institutet in Stockholm. According to Larsson, the link between chocolate and stroke is clear.

"We looked at the connection between the consumption of chocolate and stroke among women and we found that the women who ate chocolate had a lower risk of suffering from stroke."

A stroke happens when the blood supply to the brain is cut off, causing brain cells to be damaged or die. This is often caused by high levels of cholesterol that clogs the arteries.

According to Larsson the oxidation of the cholesterol is the real culprit, and chocolate contains flavonoids, which prevents this from happening.

This effect is combined with chocolate lowering blood pressure, another culprit when it comes to stroke. Larsson says:

"We believe it is because of the flavonoids in the pure cocoa. These flavonoids are a type of polyphenol that acts as a antioxidant and they decrease the risk of oxidation of cholesterol. We have also seen that the consumption of chocolate lowers blood pressure, which is a strong risk factor when it comes to stroke."

The study did not differentiate between light or dark chocolate. But in the late 90s around 90 per cent of the chocolate consumed was the light variety, with less than 30 per cent cacao.

So when can we expect to be told to eat more chocolate? Larsson says more studies will have to be done.

"We would need a few more studies that show the same result and, in different populations and also in men."

But regarding chocolate, it seems people don't need that much study to guide them. Because we know that chocolate makes us happy. And when you are happy you are also healthy.

For CRI, I am Li Dong.