An observational study analysing the eating habits of 31,823 women suggests that only moderate consumption of high quality chocolate has a positive impact on heart failure risk.
The study published in Circulation: Heart Failure, a journal of the American Heart Association, sought to examine the long-term effects of eating chocolate on heart failure risk.
Risk reduction potential
Comparing data on the amount of chocolate women ate and their risk of heart failure, the researchers led by Murrray Mittleman of Harvard Medical School found that women who ate one to two servings of high quality chocolate a week had a 32 per cent lower risk of heart failure.
On the other hand, those who had one to three servings per month had only a 26 per cent lower risk. And those who ate one serving daily or more appeared not to benefit from any risk reduction effect.
The observational data comes on the back of a body of research pointing to the positive impact of flavonoids in chocolate on blood pressure levels. It is the flavanols found in cocoa that are thought to be responsible for lowering blood pressure.
Chocolate consumption limits
But evidence of their heart health benefits is not necessarily an invitation to eat more chocolate. The evidence from the latest study suggests that there is a certain limit above which more chocolate, even high cocoa chocolate, could stop being of any benefit.
“You can’t ignore that chocolate is a relatively calorie-dense food and large amounts of habitual consumption is going to raise your risks for weight gain,” said Mittleman, who is director of the Cardiovascular Epidemiology Research Unit at Harvard Medical School’s Beth Israel Deaconess Medical Center in Boston.
The data used in the study is taken from the Swedish Mammography Cohort, which includes responses to a food frequency questionnaire of 31,823 Swedish women aged 48 to 83 years old. This information was then compared to data from national Swedish hospitalisation and death registries between 1998 and 2006.
When discussing the implications of the research, the authors warned that the quality of the chocolate in Sweden should be kept in mind. During the period of the study milk chocolate in the country contained about 30 per cent cocoa solids whereas in the US even dark chocolate may contain only 15 per cent cocoa solids. What and how much are both relevant when assessing the potential heart health benefits of chocolate.
Source: Circulation: Heart Failure
DOI: 10.1161/CIRCHEARTFAILURE.110.944025, published online Aug 16, 2010
Chocolate Intake and Incidence of Heart Failure: A Population-Based, Prospective Study of Middle-Aged and Elderly Women
Authors: M. Mittleman, E. Mostofsky, E. Levitan, and A. Wolk