Chocolate Soothes the Fluttering Heart

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  Last updated June 2, 2017 at 11:20 am


Weekly chocolate treats may make your heart happy, 1 serving/week for women and 2-6 servings/week for men may reduce risk of heart flutter.

An international study published today in the journal Heart suggests that eating chocolate regularly may be linked to a reduced risk of atrial fibrillation, more commonly known as heart flutter.

More than 33 million people worldwide are affected by atrial fibrillation and one in four adults are likely to develop it during their lives. Causes of atrial fibrillation are unclear, there are no cures and little is known about their prevention.

Eating chocolate, particularly the dark variety, has been linked to improvements in heart health so an international team of researchers from USA, Denmark and Canada were curious to know if eating chocolate could lower the rate of rate of atrial fibrillation. They turned to the Danish Diet, Cancer and Health Study and drew out the data for 55,502 participants (26,400 men and 29,100 women), aged between 50 and 64.

Participants recorded their usual weekly chocolate consumption but they were not asked to specify which type of chocolate they ate. Most chocolate eaten in Denmark, however, is milk chocolate. Over an average of 13.5 years, 3346 new cases of atrial fibrillation were diagnosed within the study.

After accounting for other heart disease factors the researchers were able to show that the rate for newly diagnosed atrial fibrillation was 10% lower for people who had 1-3 servings of chocolate a month than in people who had less than 1 serving a month. For reference, in the study,  1 serve = 1 ounce/30 g.

And, broadly speaking, there was a greater effect with the more chocolate consumed. People with 1 serving per week had a 17% lowering of atrial fibrillation while those who had between 2 and 6 serving per week had a 20% lowering. 1 or more daily servings gave a 14% lowering.

The incidence of atrial fibrillation was lower among women than among men irrespective of intake and the strongest association for women was 1 weekly serving of chocolate giving a 21% lower risk while men who had between 2 to 6 weekly servings experienced a 23% lower risk.

As encouraging as these results sound a cautionary note was sounded that this is only an observational study and there were several problems with it. In an accompanying editorial it was pointed out that the chocolate eaters in the study were healthier and more highly educated which might have influenced the findings. There were other risk factors, such as kidney disease and breathing problems at night (sleep apnoea), that were not taken into account. Furthermore, the study only included diagnosed cases of atrial fibrillation and it was pointed out that cocoa solid levels vary in different parts of the world, so the findings might not apply elsewhere.

However, the reviewers noted that, regardless of the limitations of the Danish chocolate study, the findings are interesting and warrant further consideration.

This study does not show cause and effect so we don’t know why chocolate has this effect on the heart. So before you start bingeing on chocolate, remember it is often high in sugar and fat, which will do your heart more harm than good.

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About the Author

Paul Willis
Paul is a respected leader in the science community with an impressive career in science. He has a background in vertebrate palaeontology, studying the fossils of crocodiles and other reptiles. He also has a long history as a science communicator, with a career spanning as Director of The Royal Institution of Australia, presenter and host for Australia’s Science Channel, working for the ABC on TV programs such as Catalyst and Quantum as well as radio and online. He’s written books and articles on dinosaurs, fossils and rocks and is finding new ways to engage the people of Australia with the science that underpins their world. Follow him on Twitter @fossilcrox.

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The Royal Institution of Australia is an independent charity, and the sister organisation of the prestigious Royal Institution of Great Britain, tasked with promoting public awareness and understanding of science.

The Royal Institution of Australia is passionate about building and connecting communities engaged with science, and as such works closely with scientific organisations, institutions, universities from Australia, and leaders to inspire the next generation of innovators and to create a lasting legacy for Australia.

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