Eating a small amount of chocolate every week or so may decrease the risk of a common and serious type of irregular heart rhythm, according to a new study of people from Denmark.
People who ate chocolate once a week were 17 percent less likely to be diagnosed with atrial fibrillation than those who ate the treat less than once a month, researchers from the Harvard T.H. Chan School of Public Health and the Beth Israel Deaconess Medical Center in Boston found.
Chocolate, flavanols and heart health
Eating cocoa and cocoa-containing foods may help heart health because they have a high concentration of flavanols, phytochemicals that research suggests serve as antioxidants, lower inflammation, reduce cholesterol, keep arteries elastic, enhance blood flow, inhibit blood clots and improve insulin sensitivity – all of which are related to better heart health.
The flavanol content of chocolate can vary considerably depending on the amount of cocoa solids it contains. The more cocoa solids – indicated by a percentage on labels of dark chocolate – the more flavanols.
Dark chocolate has more flavanols than milk chocolate; white chocolate – which isn’t chocolate at all – contains none.
Past studies have that found eating chocolate - especially dark chocolate - is tied to better measures of heart health and decreased risk for certain conditions like heart attacks and heart failure.
What is atrial fibrillation?
At least 2.7 million people in the U.S. and 350,000 Canadians have atrial fibrillation, a condition involving an irregular heart rhythm, known as an arrhythmia. Atrial fibrillation is the most common type of arrhythmia.
Generally, the risk of developing atrial fibrillation increases with age and with other risk factors such as diabetes, high blood pressure and underlying heart disease. One of the main complications of atrial fibrillation is stroke; individuals with atrial fibrillation have a risk of stroke that is 3 to 5 times greater than those without atrial fibrillation.
About the study
For the study, the researchers used data collected for a long-term study of 55,502 people in Denmark. The men and women were between 50 and 64 years old when it began, and they provided information about their diets when they entered the study between 1993 and 1997.
The researchers then linked dietary data to Denmark's national health registries to see who was diagnosed with atrial fibrillation over the next 13.5 years.
Moderate chocolate intake protective
Based on their diets at the beginning of the study, people who ate one serving (about 1 ounce or 28 grams) of chocolate per week were 17 percent less likely to be diagnosed with atrial fibrillation by the end of the study than people who reported eating chocolate less than once a month.
Those who ate 2 to 6 ounces per week were 20 percent less likely to be diagnosed with atrial fibrillation while those who ate more than an ounce of chocolate a day were 16 percent less likely to have the condition.
Among women, the biggest risk reduction was tied to eating one serving of chocolate per week. For men, the biggest reduction came with eating two to six servings per week.
The study was observational in nature and therefore cannot say for certain that it was the chocolate that prevented atrial fibrillation.
The researchers also caution that they can't account for unmeasured factors, such as kidney disease and sleep apnea, conditions that may influence the risk of atrial fibrillation. They also didn't collect data on the type of chocolate or the amount of flavanols consumed.
The data also suggests the people who ate the most chocolate consumed more calories but had a lower body mass index - a measure of weight in relation to height - than people who ate the least chocolate. It’s possible that these people were more physically active.
Experts say a double-blind randomized controlled trial is needed to evaluate the true efficacy of chocolate for the prevention of atrial fibrillation and to find out how much cocoa is required to do so.
Source: Heart, online Mary 23, 2017.
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