Chocolate is good for your heart - but only if it's dark

Chocolate is good for your heart - but only if eaten in small quantities and with no added milk, a new study has revealed.

Levels of antioxidants - known to be beneficial to health - in the bloodstream have been found to increase after moderate amounts of dark chocolate are eaten. The effect, however, does not happen when people eat milk chocolate, or plain chocolate with a glass of milk, said Alan Crozier, a biomedical scientist at Glasgow University.

Working with researchers from the Italian National Institute for Food and Nutrition Research in Rome, Dr Crozier found that dark chocolate contains double the amount of antioxidants called epicatechins than milk chocolate.

By feeding 100 grams of plain chocolate to one group of volunteers, 200g of milk chocolate to another and 100g of plain chocolate and a glass of milk to a third, the scientists discovered that milk seems to prevent the absorption of antioxidants into the bloodstream.

"Levels of antioxidants in the blood plasma rose by 18 per cent in those who ate dark chocolate on its own," Dr Crozier said.

The study, published in the journal Nature, suggests that any beneficial effects of antioxidants in cocoa beans could easily be offset by what else is present in a chocolate bar.

"Our findings indicate that milk may interfere with the absorption of antioxidants from chocolate in vivo and may therefore negate the potential health benefits that can be derived from eating moderate amounts of dark chocolate," the researchers write.

Dr Crozier suspects that the antioxidants in chocolate bind to proteins in milk, so preventing their absorption by the digestive system, andthe supposed benefit of eating chocolate is similar to the story about red wine. "People should not see this as evidence to binge on dark chocolate. It should only be consumed in moderation because chocolate also contains saturated fats," he said.

The research was not funded by the chocolate industry.