Last year, there appeared a study published by University of L’Aquila professor Davide Grassi and his colleagues, which reported on the subjects of the test – healthy, young volunteers – who, after a seven day period without cocoa, ate ten decagrams of chocolate each day for a period of 15 days. Based on a random assignment, half of the group consumed plain chocolate, and the other half white chocolate; then, after the two weeks had elapsed, there followed another week without chocolate, after which they switched types of chocolates: whoever had “taken” dark chocolate previously now continued with white, and the white chocolate eaters now switched to plain chocolate.

The researchers measured the test subjects’ blood pressure each day, and at the end of each treatment period also determined the various data relating to their sugar metabolisms. The results startled the entire world. During the dark chocolate “treatment” period, blood pressure decreased measurably, and insulin resistance improved markedly. This beneficial effect was lacking in the case of eating white chocolate. The authors concluded that as an effect of the flavanols, the cells of the inner layer of the blood vessels produced more of the blood vessel-dilating substance nitrogen monoxide, and this is why blood pressure declined. The improvement in insulin sensitivity is quite a significant change, because this reduces the risk of so-called metabolic syndrome (diabetes, high blood pressure, a reduction of the level of the “good” HDL cholesterol, and higher levels of harmful lipid groups, as well as an increase in abdominal fat).

The previous test was carried out on healthy, young people, but, in August of 2006, another team released a study in which both young volunteers and those aged over  50 years drank specially prepared flavanol-rich liquid chocolate every day for several days. The instrument-based measurements carried out on the test subjects showed that the flexibility of the blood vessels improved after consuming the chocolate drink, but the truly exciting and encouraging result was that this positive effect turned out to be much more pronounced in the older group.

The blood vessel-protecting effect of dark chocolate had already been observed previously. An American researcher, Norman K. Hollenberg, had carried out tests in Panama. Among the members of the Kuna Indian tribe, high blood pressure was hardly ever found; however, of those genetically identical Kuna Indians who had moved to Panama City, more and more saw their blood pressure increasing pathologically. The researchers found that the members of the Indian tribe, in their customary environment and as part of their traditional dietary regimen, drank a great deal of home-made “chocolate” made from cocoa beans, but gave up this habit when they moved to the city.

Dutch doctors made a study of the elderly inhabitants of the town of Zutphen, regularly and carefully monitoring the health of these elderly gentlemen over a decade and a half. They tracked the lives of nearly 500 men, whose age was between 65 and 85 at the start of the study, and who were without complaints and classified as healthy. They examined how the blood pressure of the subjects changed over time, and if one of them became sick or died, what the reason for this was.

The subjects with the lowest blood pressure during the fifteen-year observation period were those who had consumed the most chocolate regularly, and the coronary and circulatory mortality rate of the chocolate lovers was half that of those who refrained from eating, or only rarely ate, chocolate. Their calculations show that 100 grams of dark chocolate a day reduces blood pressure to the extent that, as a result, the risk of heart attack or stroke will be around 21% lower. This is not surprising, because there is also data indicating that flavanols improve blood flow not only through their effect of dilating the blood vessels, but also prevent increased thrombosis, and thereby reduce the risk of heart attack and stroke in this way as well.

Budapest, 25 August 2006

Dr Lajos Matos – Dr Margit Lengyel