Good news for chocolate lovers, especially now that Easter and chocolate eggs are approaching. In fact, cocoa seems to protect the heart and blood vessels from the effects of stress. Stress, in the long run, could indeed deteriorate the endothelial function, which is the lining of blood vessels and the heart, and increase the risk of cardiovascular problems. This is what emerges from a very recent scientific research published in the Nutrients journal by an English team from the University of Birmingham (Baynham et al, Nutrients, 2021).
Stress and heart
Mental stress is one of the problems in our society. Even in young and healthy people this stress causes temporary alterations in the cardiovascular system with an increase in blood pressure and heart rate. Not only that, it has been observed that even after an hour and a half from the end of the stressful moment, there may be consequences, always transitory, such as the temporary decline in endothelial function. And this happens to both young and old people, in healthy persons or with problems such as metabolic syndrome. But stress can also cause a reduction in mediated flow dilation, which is the dilation of the artery as a consequence of an increase in the speed of blood flow within the vessel itself. Mediated flow dilation is considered an important indicator of endothelial health and of the ability of the cardiovascular system to adapt to new situations. A 1% reduction in mediated flow dilation is connected, in the long run, to a 13% increase in the risk of developing cardiovascular diseases. That's why scientists have wondered what we can do to counter the damage of stress.
How diet can counteract the effects of stress on the heart
Thanks to previous research it is known that exercise and a diet rich in fruits, vegetables and foods that contain antioxidants help reduce blood pressure during stress and the risk of heart attack and disease. Cocoa is a food particularly rich in antioxidants called flavonoids.
That's why the scientists recruited 30 people, all young adults under 45, to evaluate the effects of cocoa on heart and blood vessel health following mental stress. The study participants were divided into two groups. The first group was asked to take a drink prepared with 8 grams of cocoa dissolved in 300 ml of water an hour and a half before being subjected to an 8-minute test to induce mental stress. The second group, on the other hand, was served a drink prepared with processed cocoa in order to reduce almost all of the flavonoids. Volunteers underwent blood pressure, heart and endothelial function measurements before, during and after the test. What emerged was that stress caused a temporary decline in endothelial function in both groups. However, the decline was significantly less in the group that took unprocessed cocoa and the maximum amount of flavonoids. Not only that, the flavonoid-rich cocoa also resulted in an increase in peripheral blood flow. Hence, cocoa is able to counteract the damage of stress on the cardiovascular system.
In the experiment, cocoa was able to protect the endothelial function. However, no differences in blood pressure were observed. In fact, an increase was found in both groups following stress. It is likely that a daily consumption of cocoa can also counteract this increase in pressure but this is material for a future experiment, as indicated by the same authors of the study.