Atrial fibrillation is characterised by an irregular and rapid heart rate, dramatically increasing the risk of blood clot formation and stroke
Evidence suggests that the pathophysiology of atrial fibrillation begins with an inflammatory cascade, leading to production of reactive oxygen species and proliferation of fibroblasts.
This cascade leads to electrical and structural remodeling of the atrium and symptoms of atrial fibrillation. It is thought that the antioxidant properties of flavonoids in chocolate might interfere with this pathophysiologic cascade and reduce the risk of atrial fibrillation.
Numerous studies have reported that moderate consumption of dark chocolate is associated with improved cardiovascular health, including lower risks for myocardial infarction, heart failure and cardiovascular mortality.
Only two prospective studies have evaluated the association between chocolate consumption and atrial fibrillation: the Women’s Health Study reported that moderate chocolate consumption was associated with a 1-4% lower rate of self-reported atrial fibrillation, and the Physician’s Health Study reported no significant association between chocolate consumption and self-reported atrial fibrillation.
To further evaluate the association between chocolate consumption and atrial fibrillation, researchers evaluated data from a large, prospective cohort in Europe.
The study population included 55,502 adults (age range = 50-64 years) enrolled in the Danish Diet, Cancer and Health Study.
Chocolate intake was assessed at baseline, and participants were followed for a median of 13.5 years. The outcome measure was clinically apparent atrial fibrillation or atrial flutter.
A total of 3346 incident cases of atrial fibrillation occurred during follow-up.
Compared with chocolate intake of less than once a month, the rate of atrial fibrillation was lower in people consuming 1-3 servings per month (HR=0.90; 95% CI, 0.82-0.98), one serving per week (HR=0.83; 95% CI, 0.74-0.92), 2-6 servings per week (HR=0.80; 95% CI, 0.71-0.91), and one or more servings per day (HR=0.84; 95% CI, 0.65-1.90).
The association between chocolate consumption and a decreased risk of atrial fibrillation was statistically significant (p for linear trend <0.001).
This study did not evaluate the type of chocolate being consumed or the flavonoid content.
Despite adjusting for age, smoking status, and other potential confounders, it is possible that other confounding factors are responsible for the observed association.
Nevertheless, this large, 13-year prospective study suggests that moderate chocolate consumption may be associated with a decreased risk of atrial fibrillation in European men and women.