Can eating chocolate stave off an irregular heartbeat?

Eating chocolate can cut your risk of developing an irregular heartbeat by a fifth, according to research at Harvard Medical School. (But read our analysis below.)

The researchers said that flavanols – which are known to reduce cholesterol, blood pressure and inflammation – are responsible for the effect.

Writing in the British Medical Journal, they said: ‘Most of the chocolate consumed in Denmark is milk chocolate. Despite the fact that most of the chocolate consumed in our sample probably contained relatively low concentrations of the potentially protective ingredients, we still observed a robust statistically significant association.’

They tracked 55,000 people between the ages of 50 and 64 in Denmark over a period of 13 years, and found a ‘robust statistically significant association’ between chocolate consumption and a reduced chance of atrial fibrillation (also known as flutter).

For women, eating one 30g bar of chocolate a week (milk or dark) was found to be associated with a 21 per cent reduced risk. For men eating two to five chocolate bars a week appeared to reduce the risk by 23 per cent.

Atrial fibrillation causes an abnormally fast and irregular heart rate, often above 100 beats per minute. The condition can cause fatigue, shortness of breath and tiredness. It significantly increases the risk of stroke. It is believed to affect up to 900,000 people in England.

Instant analysis
It’s important to keep perspective when interpreting studies like this. Of course we would all love to believe that eating chocolate would prevent medical problems, but the likelihood of this being the case is pretty slim.

There may well be some ingredients in chocolate that have benefits, but chocolate also contains fat and sugar, which can have negative effects when consumed in excessive quantities. This is an observational study and, although confounding factors were taken into consideration, it would be very difficult to allow for all of them, especially in such a large study size.

Although the study shows an association, it cannot tell us that chocolate prevents atrial fibrillation. And we don’t need this effect to justify eating it. Instead of trying to make heroes and villains out of specific foods, we would do better to aim for a sensible, balanced diet, using moderation to factor in things that we enjoy.
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