Moderate chocolate intake may reduce the risk of atrial fibrillation – a heart condition that causes a fast and irregular heartbeat. The condition seemed to be less frequent in people who ate between one and three servings of chocolate a month.
More than 33 million people worldwide develop atrial fibrillation, which is associated with a higher risk of stroke, heart failure and dementia.
However, causes are still not completely understood. Finding effective ways of preventing atrial fibrillation is therefore a major public health preoccupation – and a goal that many scientists are aiming for.
Flavanols and the heart
This is not the only study to reach this conclusion. A number of papers have previously suggested that moderate consumption of chocolate, particularly dark chocolate, improves markers of cardiovascular health. Moderate consumption of cocoa is thought to promote cardiovascular health due to its high content of flavanols – compounds with antioxidant and anti-inflammatory benefits.
However, few have focused on atrial fibrillation specifically. Here, the scientists examined the medical data of more than 55,000 participants to a large population-based prospective cohort study known as "The Danish Diet, Cancer, and Health Study". Aged between 50 and 64 years, they had provided information on their chocolate intake at the before enrolling.
These participants were followed for a median of 13.5 years, during which 3346 cases of atrial fibrillation were reported. Analysing the data, the researchers found that the rate of atrial fibrillation rate was 10 per cent lower for people consuming between one and three servings of chocolate a month, compared to those who ate less than one serving a month.
Looking at weekly consumption of chocolate and whether the sex of individuals made any difference, the scientists established that the strongest association for women seemed to be one weekly serving of chocolate (21 per cent lower risk). For men, two to six weekly servings were associated with the lowest risk (23 per cent lower risk).
They concluded that moderate chocolate consumption potentially reduced the risk of atrial fibrillation.
While it is tempting to agree with these findings, the research does suffer from a series of limitations. Dr Tim Chico, reader in cardiovascular medicine & consultant cardiologist at the University of Sheffield, who was not involved with the study, said: "Some studies have suggested eating chocolate may have benefits for the heart, but when a health story seems too good to be true, it sadly usually is. (...) Here, they show a benefit of eating chocolate once a month or more, compared with people who eat chocolate less often than this, so the benefit is seem with very infrequent chocolate intake, with little or no benefit of eating it more often.
"In addition, this study the people eating more chocolate were actually thinner and healthier overall, both of which reduce the risk of atrial fibrillation. I suspect that the reduced risk of atrial fibrillation is more to do with these factors than their chocolate intake directly."
It is also important to note that while one serving of chocolate was defined in the study as one ounce, the scientist did not differentiate between milk chocolate and dark chocolate. How rich in cocoa a chocolate product is can greatly vary, so it is difficult to draw general conclusions from this study.
As people age, the best way to prevent atrial fibrillation and to stay healthy remains this is to maintain a healthy weight and blood pressure, perform moderate exercise regularly, and reduce alcohol.