Study: Dark Chocolate Consumption May Decrease Risk of Irregular Heartbeat

May 24, 2017 by News Staff / Source

Consuming moderate amounts of chocolate with high cocoa content was associated with lower risk of being diagnosed with atrial fibrillation — a common and potentially life threatening type of irregular heartbeat — in a study of men and women in Denmark.

               According to Mostofsky et al, moderate chocolate intake may be inversely associated with AF risk, although residual confounding cannot be ruled out. Image credit: Alexander Stein.

Atrial fibrillation (AF) is the most common arrhythmia in clinical practice, affecting 2.7–6.1 million people in the United States and 8.8 million in the European Union.
AF is associated with a higher risk of stroke, heart failure, cognitive decline, dementia and mortality, so identifying methods for preventing and identifying effective treatments for AF is of great public health importance.
Previous studies suggest that moderate consumption of cocoa and cocoa-containing foods — in particular, dark chocolate, which has a higher cocoa content than milk chocolate — may promote cardiovascular health due to their high content of flavanols, a subgroup of polyphenols with vasodilatory, antioxidant and anti-inflammatory benefits.
But there is only limited research on the association between consuming chocolate and the occurrence of AF.
            “Our study adds to the accumulating evidence of the health benefits of moderate chocolate intake and highlights the importance of behavioral factors for potentially lowering the risk of arrhythmias,” said study lead author Dr. Elizabeth Mostofsky, a postdoctoral fellow at Beth Israel Deaconess Medical Center and an instructor in the Department of Epidemiology at Harvard T. H. Chan School of Public Health.
“This study adds to the growing body of evidence that, compared with other snacks or treats, eating small amounts of dark chocolate on a regular basis as part of an overall balanced, heart-healthy diet is a good option that may reduce the risk of cardiovascular disease,” said co-author Dr. Murray Mittleman, a preventive cardiologist at Beth Israel Deaconess Medical Center and a professor of epidemiology at Harvard T.H. Chan School of Public Health.
            The study included 55,502 men and women participating in the Danish Diet, Cancer and Heath Study.
Dr. Mostofsky, Prof. Mittleman and their colleagues obtained information on the study participants’ body mass index, blood pressure and cholesterol, which were measured when participants were recruited between 1993 and 1997.
They also looked at participants’ health conditions, including high blood pressure, diabetes, or cardiovascular disease as well as data on their diet and lifestyle gathered from questionnaires.
Using a validated questionnaire, the authors collected information about the participants’ daily chocolate intake.
            Among the participants recruited, 3,346 cases of AF occurred over a 13.5 year follow-up period based on data collected from the Danish National Patient Register.
Compared with participants who ate a one-ounce serving of chocolate less than once per month, participants who ate one to three servings per month had a 10% lower rate of AF; those who ate one serving per week had a 17% lower rate; and those who ate between two and six servings per week had a 20% lower rate.
The benefit leveled off slightly with greater chocolate consumption, with those eating one or more servings per day having a 16% lower AF rate on average. Results were similar for men and women.
            “Despite the fact that most of the chocolate consumed by the study participants likely had relatively low concentrations of potentially protective ingredients, we still observed a significant association between eating chocolate and a lower risk of AF, suggesting that even small amounts of cocoa consumption can have a positive health impact,” Dr. Mostofsky said.
“Eating excessive amounts of chocolate is not recommended, however, because many chocolate products are high in calories from sugar and fat and could lead to weight gain and other metabolic problems.”
“But moderate intake of chocolate with high cocoa content may be a healthy choice.”
The findings were published online this week in the journal Heart.
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Elizabeth Mostofsky et al. Chocolate intake and risk of clinically apparent atrial fibrillation: the Danish Diet, Cancer, and Health Study. Heart, published online May 23, 2017; doi: 10.1136/heartjnl-2016-310357