Eat dark chocolate, reduce blood pressure

7 July, 2007:

Dark chocolate helps reduce blood pressure, but over-indulgence can cause harm.

A new study by researchers in Germany has found that dark chocolate is good for your heart. The study has been published in the Journal of the American Medical Association.

Researchers say that dark chocolate may stave off hardening of the arteries among smokers, and it has more antioxidants per gram than red wine, green tea or berries. Chocolates are made from cocoa – from dried and partially fermented fatty seed of the cacao tree. Cocoa contains flavonoid, a type of chemical that researchers say has been shown to improve blood flow and reduce blood pressure.

Other studies have shown that milk chocolate, white chocolate, or dark chocolate eaten with milk do not have the same benefits as plain dark chocolate.

Dark chocolate contains chemicals called polyphenols, which seem to increase the production of a substance in the body called nitric oxide that causes the blood vessels to widen, making more room for the blood to flow and thus lowering blood pressure.

Researchers at the University Hospital of Cologne, Germany, studied 44 people with raised blood pressure, putting them into two groups. One ate 6
grams of dark chocolate daily, the other the same amount of white chocolate.

The people were between 56 years and 73 years, with either upper-range pre-hypertension (blood pressure between 130/85 and 139/89) or stage 1 hypertension (blood pressure between 140/90 and 160/100). None of those eating dark chocolate registered changes in body weight or their levels of glucose and lipids.

Their systolic blood pressure (the upper reading which measures the force of blood as the heart beats) fell by 2.9 mm and their diastolic blood pressure (the lower figure taken as the heart relaxes) dropped by 1.9 mm.

In fact, the suggestion that cocoa is beneficial for health is not new. Previous research had suggested that it could bring down blood pressure. However, it had been thought that large quantities were needed to achieve the desired effect and that the benefits would then be offset by the consequences of consuming the high levels of fat and sugar associated with cocoa products.

But the German researchers said they have now shown that benefits can be achieved with a small amount – 30 calories worth of chocolate – and that the blood pressure reduction was small but the effects were clinically noteworthy.

A reduction of 3 mm in blood pressure could reduce the relative risk of stroke mortality by 8%, of coronary artery disease by 5%, and of all-cause
mortality by 4%, the researchers said.

They also stressed that asking people to consume a couple of chunks of chocolate a day was far easier than encouraging “complex behavioral changes” to help them reduce their blood pressure.

However, Sara Stanner, nutritionist of the British Heart Foundation, warned that it is important to remember that chocolate is also high in fat and calories and so over-indulgence is not good for the heart.