Eating dark chocolate daily could help reduce blood pressure, a new study into the benefits of the food has suggested.

An analysis of 20 studies showed that chemicals in the cocoa - the key ingredient in chocolate - helped to relax blood vessels, according to a report by the Cochrane Group.

Combining several previous studies - which varied the amount of cocoa that was consumed - a small reduction in blood pressure was noticed over a two-week period, although longer term effects are unknown.

Lead researcher from the National Institute of Integrative Medicine in Melbourne Karen Ried said: "Although we don't yet have evidence for any sustained decrease in blood pressure, the small reduction we saw over the short term might complement other treatment options and might contribute to reducing the risk of cardiovascular disease."

While it may have beneficial attributes, dark chocolate should be eaten as part of a healthy and balanced diet in order to lower blood pressure.