More support for dark chocolate’s heart benefits
By Stephen Daniells
A daily treat of dark chocolate can improve overall heart health and
reduce the risk of heart disease, say researchers from Zurich.
â€œOnly a small daily treat of dark chocolate may substantially
increase the amount of antioxidant intake and beneficially effect
vascular health,â€ said Dr F. Hermann and colleagues from University
Dark chocolate is a rich source of antioxidants, and contains more
polyphenols per gram than green tea or red wine.
The research, published in the journal Heart (vol 92, pp 119-120),
compared the effects of dark or white chocolate on blood flow and the
platelet activity of 20 healthy male smokers.
Smokers were chosen as the study group because smoking is a major
risk factor in cardiovascular health. Endothelial cells, which line
the walls of the arteries, are affected by cigarette smoke, both
passive and active. Platelets contribute to blood clotting and then
The volunteers were randomly divided into two groups and, after a
24-hour period of abstinence from polyphenol rich foods, were given
40g of dark or white chocolate.
â€œDark but not white chocolate induced a rapid and significant
improvement of endothelial and platelet function in healthy smokers
two to eight hours after ingestion,â€ said the researchers.
â€œThe high flavonoid content of dark chocolate may potentially
explain the mechanisms for the reduced platelet activation,â€
Endothelium dysfuntion is caused by reactive oxygen species, but the
high antioxidant content of the dark chocolate slows or blocks these
The new study adds to a growing body of research about the beneficial
effects of chocolate on heart health. Previous studies published in
the American Journal of Hypertension (Vol. 18, Issue 6, pp. 785-791)
and the Journal of the American College of Cardiology (Vol. 46,
pp.1276-1283), also reported positive effects of dark chocolate on
the health of smokers’ blood vessels.
Other studies have claimed promising results against a wide range of
conditions including blood pressure, diarrhoea, breast cancer
prevention and decreasing the effects of aging on the brain.
The Zurich researchers were careful to stress that further research
is required to study the long-term effects of polyphenols on health.
Moderation with chocolate consumption was also stressed particularly
since it may adversely affect heart health because of sugar and fat
The chocolate industry has however already profited from the wave of
positive health effect of cocoa, with producers increasingly
highlighting polyphenol content on their labels.