Bilthoven, the Netherlands - Consuming cocoa was associated with lower blood pressure and a reduced risk of death in a new observational study in elderly men [1].

The study, published in the February 27, 2006, issue of the Archives of Internal Medicine, was conducted by a team led by Brian Buijsse (National Institute for Public Health and the Environment, Bilthoven, the Netherlands).

The researchers note that cocoa contains flavanols, which have been linked to lower blood pressure and improved endothelial function, and that small randomized trials have shown similar benefits with chocolate or cocoa, but that the products tested generally contained much higher amounts of flavanols than commercially available chocolate products do.

They conducted an observational study in which they estimated cocoa intake in a sample of 470 elderly Dutch men and investigated whether cocoa intake was related to blood pressure and cardiovascular mortality. The men underwent physical examinations and were interviewed about their dietary intake when they enrolled in the study in 1985 and at follow-up visits in 1990 and 1995. The researchers then placed them into three groups based on their level of cocoa consumption. Information about their subsequent illnesses and deaths were obtained from hospital or government data.

Results showed that over the 15-year study period, men who consumed cocoa regularly had significantly lower blood pressure than those who did not. After adjustment for a host of lifestyle and dietary factors, the mean systolic blood pressure in the highest tertile of cocoa intake was 3.7 mm Hg lower than the lowest tertile, and the mean diastolic blood pressure was 2.1 mm Hg lower.

Over the course of the study, 314 men died, 152 due to cardiovascular diseases. Men in the group with the highest cocoa consumption were half as likely as the others to die from cardiovascular disease, and they were also less likely to die of any cause.

Buijsse et al say that they believe this to be the first epidemiological study reporting inverse relationships of cocoa intake with blood pressure and with cardiovascular and all-cause mortality. They point out that one previous study has suggested a lower risk of all-cause mortality in people who eat candy vs those who don't, but no differentiation was made between chocolate and sugar candy. However, in the Nurses' Health Study, the frequency of consumption of chocolate was not associated with a lower risk of coronary heart disease after 14 years of follow-up.

They note that the blood-pressure reduction in the current study was associated with a usual daily cocoa intake of about 4.2 g, which is equal to 10 g of dark chocolate per day. "Although this amount is one tenth of the dose that is used in most intervention studies, it suggests that long-term daily intake of a small amount of cocoa may lower blood pressure," they comment.

The researchers further point out that the lower cardiovascular-mortality risk associated with cocoa intake in this study could not be attributed to the lower blood pressure observed with cocoa use, and they suggest that the known improvement of endothelial function by flavanols in cocoa may instead be the mechanism behind the lower cardiovascular mortality. But they add that cocoa-containing foods and flavanols may also reduce cardiovascular risk by the inhibition of platelet function and low-density-lipoprotein oxidation, the modulation of cytokine production, and a beneficial effect on serum cholesterol levels.

They also note that cocoa is a rich source of antioxidants, and it may therefore also benefit other conditions linked to oxidative stress (eg, pulmonary diseases and certain types of cancer), which could have contributed to the lower all-cause mortality seen. But they caution that these results could also be due to residual confounding and therefore confirmation by other studies is needed.