Eating Dark Chocolate Can Protect Your Heart

Chocolate has always been the "magical" cure-all ingredient for our ailments. We often eat chocolate in the form of candy to lift our mood or mend a broken heart. Now, researchers at Harvard T.H. Chan School of Public Health in Denmark suggest the rich cocoa candy could also protect our heart health by decreasing the risk of irregular heartbeat.

Eating up to six servings of chocolate per week led to a 20 percent lower risk of being diagnosed with atrial fibrillation (AF) — a common and dangerous type of irregular heartbeat. Previous research proposes cocoa and cocoa-containing foods, like dark chocolate, possess heart health benefits because their high flavanol content promotes the healthy function of blood vessels. In the Danish study, the chocolate consumed had relatively low concentrations of possible protective ingredients, though there was still a significant association between small amounts of cocoa consumption and better heart health.

"Our study adds to the accumulating evidence on the health benefits of moderate chocolate intake and highlights the importance of behavioral factors for potentially lowering the risk of arrhythmias," said Elizabeth Mostofsky, lead author of the study, instructor in the Department of Epidemiology at Harvard Chan School, and a postdoctoral fellow at Beth Israel Deaconess Medical Center, in a statement.

In the study, published in Heart, researchers analyzed a total of 55,502 men and women participating in the Danish Diet, Cancer, and Health Study, who had their body mass index, blood pressure, and cholesterol measured during recruitment (from December 1993 and May 1997). Participants' health conditions, such as high blood pressure, diabetes, or cardiovascular disease, and data on their diet and lifestyle from questionnaires, were also taken into account. During the 13.5-year follow-up period, there were 3,346 cases of atrial fibrillation.

Mostofsky and her research team found men and women who ate one to three servings of chocolate per month had a 10 percent lower rate of AF than those who ate a one-ounce serving less than once a month. Meanwhile, those who ate one serving per week had a 17 percent lower rate, and those who consumed two to six servings per week had a 20 percent lower rate. However, this benefit tapered off for those who ate one or more servings per day; they experienced only a 16 percent lower AF rate.

So, how much chocolate is too much? It depends.

Mostofsky cautions we should be mindful of over-indulgence.

"Eating excessive amounts of chocolate is not recommended 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," she said.

Previous research has found high consumption of chocolate can lead to more heart health benefits, but moderation is key. A 2015 study published in Heart found participants who ate 15 to 100 grams of chocolate a day, from candy bars to hot cocoa, had a lower risk for heart disease and stroke than those who did not eat any chocolate. To put things into perspective, 100 grams is the equivalent of two classic Hershey's bars, which can lead to a minimum intake of 500 calories.

Eating more dark chocolate was also linked to lower body mass index (BMI), waist to hip ratio, systolic blood pressure, and inflammatory proteins. These participants also saw a 11 percent lower risk of heart disease, and a 25 percent lower risk of associated death. Interestingly, the study also noted more participants ate milk chocolate versus dark chocolate, which has long been considered healthier.

Both milk chocolate and dark chocolate contain cocoa, but dark chocolate has a higher concentration, and could be more potent in protecting heart health. A general rule is the more cocoa a chocolate bar has, the more flavonoids it possesses, and the better it is for our health. The effect eating chocolate has on our bodies is encouraging, and rids us of guilt. It could also lead to an effective treatment in common heart ailments that can provide better and more consistent results.

So, it seems like chocolate can really protect our heart.

Source: Mostofsky E, Johansen Berg M, Tjonneland A et al. Chocolate Intake and Risk of Clinically Apparent Atrial Fibrillation: the Danish Diet, Cancer, and Health Study. Heart. 2017.