A recent study published in the American Journal of Clinical Nutrition showed that when individuals were given a diet supplemented with cocoa powder and dark chocolate, risk for heart disease was reduced.

There are two main events that lead to coronary heart disease.

The first of these is the process called atherosclerosis, which causes narrowing of the blood vessels. It happens when a type of fat in the blood called low density lipoprotein cholesterol (LDL cholesterol) accumulates and oxidizes and causes the vessels to 'fur up'. This leads to a reduced flow of blood to the heart and may cause chest pain (angina), particularly during exercise.

The second event is called thrombosis. This is when a large blood clot forms in the vessel, stopping the blood supply from reaching the heart. This is a heart attack.

Cocoa powder and dark chocolate are rich sources of flavonoids. These are compounds of plant origin with antioxidant effects that can protect against heart disease.

Flavonoids act by inhibiting LDL cholesterol oxidation and reducing the ability of the blood to clot. The researchers aimed to assess the effects of a diet high in cocoa powder and dark chocolate on LDL oxidation, the total antioxidant capacity of the blood to fight free radicals, and prostaglandin concentrations, which give an indication of the body’s ability to form blood clots.

The researchers feed 23 volunteers two different diets. One was a normal diet and the second was supplemented with 22 grams of cocoa and 16 grams of dark chocolate per day.

The study showed that LDL oxidation was slower by 8% in those who ate the cocoa rich diet, that serum total antioxidant capacity was around 4% greater, HDL cholesterol (a type of cholesterol that is beneficial to heart health) was 4% greater but that prostaglandin was not significantly different between the two groups. The researchers concluded that cocoa powder and dark chocolate might favourably affect cardiovascular disease risk status.

While that may be good news for those of us trying to protect our heart health, for those who are trying to watch our waistlines the story remains the same – an average chocolate bar (2 oz, or 56 grams) will provide you with almost 300 calories and 17 grams of fat. Therefore, chocolate should only be eaten in limited amounts and you should choose dark chocolate instead of milk or white chocolate, as the flavonoid levels are higher.