The authors of the study said that they assessed 19,357 people, who were aged between 35 and 65, and evaluated their chocolate consumption for a period of at least ten years.
The researchers said that they found that those who ate the most amount of chocolate – an average of 7.5 grams a day – had lower blood pressure and a 39 per cent lower risk of having a heart attack or stroke compared to those who ate the least amount – an average of 1.7 grams a day.
Lead researcher, Dr Brian Buijsse, a nutritional epidemiologist at the German Institute of Human Nutrition in Nuthetal, Germany, said that if people in the group eating the least amount of chocolate increased their intake by six grams a day, 85 fewer heart attacks and strokes per 10,000 people could be expected to occur over a period of about ten years.
He also claims that if the 39 per cent lower risk is generalised to the general population, the number of avoidable heart attacks and strokes could be higher because the absolute risk in the general population is higher.
Though further research is needed, Buijsse said that flavanols appear to be the substances in cocoa that are responsible for lowering blood pressure and boosting heart health.
He said that these substances appear to improve the bioavailability of nitric oxide from the cells that line the inner wall of blood vessels:
“Nitric oxide is a gas that, once released, causes the smooth muscle cells of the blood vessels to relax and widen; this may contribute to lower blood pressure. Nitric oxide also improves platelet function, making the blood less sticky, and makes the vascular endothelium less attractive for white blood cells to attach and stick around.”
The British Heart Foundation (BHF), in response to the study, has sounded a note of caution. BHF senior heart health dietician, Victoria Taylor, said that it was important to read the small print attached to the study.
“The amount consumed on average by even the highest consumers was about one square of chocolate a day or half a small chocolate Easter egg in a week, so the benefits were associated with a fairly small amount of chocolate,” she argues.
According to Taylor, as a result of the media attention given to the findings of studies such as these some consumers will be tempted to eat more than one square: “However, chocolate has high amounts of calories and saturated fat which are linked to weight gain and raised cholesterol levels - two of the key risk factors for heart disease,” stressed the dietician.
And Buijsse also warned that it was important people ensured that eating chocolate did not increase their overall intake of calories or reduce their consumption of healthy foods.
“Small amounts of chocolate may help to prevent heart disease, but only if it replaces other energy-dense food, such as snacks, in order to keep body weight stable,” he said.
The participants in the study, said the authors, received medical checks, including blood pressure, height and weight measurements between 1994 and 1998. They also answered questions about their diet, lifestyle and health, continued the researchers.
Furthermore, participants were asked how frequently they ate a 50g bar of chocolate, and the researchers added, that a question was not included about whether the chocolate was white, milk or dark chocolate.
However, the researchers said sub-set of 1,568 participants were asked to recall their chocolate intake over a 24-hour period and to indicate which type of chocolate they ate to give indications that might be expected for the complete study cohort.
In this sub-set, found the researchers, 57 per cent ate milk chocolate, 24 per cent dark chocolate and two per cent white chocolate.
The researchers allocated the participants to four groups (quartiles) according to their level of chocolate consumption.
According to the report, follow-up questionnaires were sent out every two or three years until December 2006, with the study participants asked whether they had had a heart attack or stroke, information which was subsequently verified by medical records from general physicians or hospitals.
The German researchers found that during the eight years there were 166 heart attacks (24 fatal) and 136 strokes (12 fatal) with people in the top quartile having a 27 per cent reduced risk of heart attacks and nearly half the risk (48 per cent) of strokes, compared with those in the lowest quartile.
Mars Botanical’s Risa Schulman will give a presentation at the upcoming NutraIngredients Antioxidants 2010 Conference in Brussels, on the topic of cocoa flavanols. For more information and to register, please click here.
Source: European Heart Journal
Published online ahead of print - doi:10.1093/eurheartj/ehq068
Title: Chocolate consumption in relation to blood pressure and risk of cardiovascular disease in German adults
Authors: B Buijsse, C Weikert, D Drogan, M Bergmann, H Boeing.