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Come over to the dark side (of chocolate)

27 May, 2014

It’s official – researchers have found how and why dark chocolate is actually good for you.

Apparently it helps restore flexibility to arteries while also preventing white blood cells from sticking to the walls of blood vessels. Both arterial stiffness and sticking white blood cells are known factors in atherosclerosis – a disease where the arteries become narrowed and hardened from a build-up of plaque around the artery wall. This disrupts blood flow and can cause cardiovascular problems (such as heart attack and stroke).

In the study by a team from Wageningen University, The Netherlands, and the University of Glasgow, 44 middle-aged overweight men were given 70 grams of chocolate per day over two 4-week periods. The study used regular dark chocolate and specially prepared dark chocolate with high flavanol content, as the researchers wanted to test whether chocolate enriched with flavanols had additional benefits. Flavonols are the main type of flavonoid found in cocoa and chocolate, and previous research has suggested that their antioxidant qualities have an influence on cardiovascular health. Both chocolates had a similar cocoa mass content.

Before and after both 4-week periods, the researchers performed a variety of measurements that are important indicators of vascular health. Overall, they found a 4-week chocolate intake increased flow-mediated dilation by 1%, with a corresponding decrease in “augmentation index, leukocyte cell count, plasma sICAM1 and sICAM3 and leukocyte adhesion marker expression”. There was no difference in these beneficial effects between high flavanol content and normal flavanol dark chocolate consumption. Indeed, the researchers found the increased flavanol adversely affected the taste of the chocolate and negatively affected the motivation of the test subjects to eat it.

During the study, participants were advised to refrain from certain energy-dense food products to prevent weight gain.

In a press release from the Federation of the American Societies for Experimental Biology (FASEB), one of the research authors, Dr Diederik Esser, from Wageningen University, said, “We provide a more complete picture of the impact of chocolate consumption in vascular health and show that increasing flavanol content has no added beneficial effect on vascular health. However, this increased flavanol content clearly affected taste and thereby the motivation to eat these chocolates.”

This research was published in the March 2014 issue of The FASEB Journal. Dr Gerald Weissmann, the Editor-in-Chief of The FASEB Journal, said the “effect that dark chocolate has on our bodies is encouraging not only because it allows us to indulge with less guilt, but also because it could lead the way to therapies that do the same thing as dark chocolate but with better and more consistent results”.


Esser, D., Mars, M., Oosterink, E., Stalmach, A., Muller, M. and Afman, L.A. (2014). Dark chocolate consumption improves leukocyte adhesion factors and vascular function in overweight men. The FASEB Journal, 28(3): 1464–1473. doi:10.1096/fj.13-239384 Abstract available from www.fasebj.org/content/28/3/1464.abstract.


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