Research revealed by The Cochrane Library found that daily consumption of dark chocolate or cocoa powder can actually lower blood pressure.

Experts said despite the effect was small, it was potentially enough to help protect people from heart disease.

Scientists studied around 865 people who consume daily helpings of dark chocolate. The chocolate products contained varying amounts of plant compounds called flavanols which are believed to benefit health.

The most flavanol-rich chocolate or cocoa was found to lower blood pressure by an average of two to three millimetres of mercury.

Mars study also  suggested that cocoa drinks may benefit the brain in old age. Flavanol-rich cocoa was said to increase the mental performance of elderly volunteers after eight weeks.