Can dark chocolates keep heart disease away? Cardiology Basics

Can dark chocolates keep heart disease away? Cardiology Basics

A study published in ‘Circulation’ – the flagship journal of American Heart Association, suggested that eating dark chocolate can decrease your risk for myocardial infarction.

Myocardial infarction is usually due to a coronary obstruction, though there are other varieties as well, according to the Universal Definition of Myocardial Infarction. High oxidative stress and limited availability of antioxidants can cause endothelial damage in the arteries, leading to increased chances for a thrombosis.

Dark chocolates (which contain 70% cocoa) have lots of flavonoids – potent antioxidants which helps to overcome the oxidative stress present in our body. They also decrease the activation of blood platelets responsible for thrombosis.

Flavonoid rich dark chocolate has the potential for a beneficial effect on graft atherosclerosis and hence this study in heart transplant recipients.

They compared the effect of flavonoid rich dark chocolate with cocoa free control chocolate on coronary vascular and platelet function in 22 heart transplant recipients in a double blind randomized study.

Coronary vasomotion was evaluated by quantitative coronary angiography and cold pressor test before and 2 hours after ingestion of 40 g dark chocolate or control.

Two hours after ingestion of flavonoid rich dark chocolate, coronary diameter increased from a mean of 2.36 mm to 2.51 mm (about 6%). Platelet adhesion also decreased in dark chocolate group while it was unchanged in the control group.

Can’t you get more flavonoids from other foods? – you may ask. But the fact remains that dark chocolate contains greater amounts of flavonoids than any other food like green tea and blueberries.

But before you reach out for that delicious dark bar, here’s something that you should remember – Although eating some of it is good for the heart, it’s still full of calories. So, you’ve got to cut down on some other food stuffs.

An editorial in The Lancet, another leading medical journal, reminds us that all dark chocolates are not created equal! This is because dark chocolate need not necessarily contain flavonoids.

The editorial pointed out that some manufacturers may remove flavanols because of the bitter taste and darken the chocolate. Flavanol content may not be there on the label as well. All that remains is fat and sugar and there is no health benefit whatsoever. Manufacturers may not reveal the content of flavonoids in their products and we have no way for finding out whether they are heart healthy or not.

So, the bottom line is, if you can’t find a label describing the amount of flavonoids in the chocolate, you better stick to the traditional heart healthy diet – a balanced diet low in sugar, salt and fat, with lots of fruits and vegetables.

References

1. Flammer AJ, Hermann F, Sudano I, Spieker L, Hermann M, Cooper KA, Serafini M, Lüscher TF, Ruschitzka F, Noll G, Corti R. Dark chocolate improves coronary vasomotion and reduces platelet reactivity. Circulation. 2007 Nov 20;116(21):2376-82.
2. The devil in the dark chocolate. Lancet. 2007 Dec 22;370(9605):2070.