Eating chocolate regularly may reduce the risk of atrial fibrillation (AF), the results of a large population-based prospective cohort study suggest.  

The investigators evaluated the association between chocolate intake and incident clinically apparent AF using data from the Danish Diet, Cancer, and Health Study. The present study involved 55,502 participants (26,400 men) aged 50-64 years who had provided information on chocolate intake using self-administered questionnaires at baseline.

The questionnaire did not differentiate between dark and milk chocolate. Most chocolate consumed in Denmark contains a minimum of 30% cocoa solids.

Incident cases of AF were documented through linkage with nationwide registries. During a median follow-up of 13.5 years there were 3,346 cases of AF.

A serving was defined as a 1 oz chocolate bar or packet. Compared with those who ate chocolate less than once per month, the rate of AF was lower for people consuming:

• 1-3 servings/month, hazard ratio (HR) 0.90 (95% CI: 0.82-0.98)

• 1 serving/week, HR 0.83 (95% CI: 0.74-0.92)

• 2-6 servings/week, HR 0.80 (95% CI: 0.71-0.91)

• ≥ 1 serving/day, HR 0.84 (95% CI: 0.65-1.09) P-linear trend < 0.0001

The results were similar for men and women.

Moderate consumption of cocoa and cocoa-containing foods may improve cardiovascular health because of their high content of flavanols which have vasodilatory, antioxidant and anti-inflammatory effects. Studies have shown that consumption of chocolate, particularly dark chocolate can result in lower rates of myocardial infarction, heart failure and cardiovascular mortality. If one considers that the pathophysiology of AF may involve an inflammatory cascade leading to electrical and structural remodelling of atrial tissue increasing AF risk then it is reasonable that chocolate could potentially lower the risk of AF.

The authors conclude that moderate chocolate consumption may reduce the risk of developing AF.

This was a large well conducted prospective cohort study. Nevertheless, the authors acknowledge that residual confounding cannot be ruled out and that more research is required.

Dr Peter Savill