The June 3, 2008 issue of the Journal of the American College of Cardiology published the results of a first-of-its kind study which showed that consuming cocoa flavanols improved vascular function in patients being treated for type 2 diabetes. Vascular dysfunction occurs early in the development of cardiovascular disease, which is a common killer of diabetic individuals. Even when diabetes is medically treated and “controlled,“ vascular dysfunction often persists.
In an initial study, Malte Kelm, MD, and colleagues at University Hospital RWTH Aachen in Germany gave 10 diabetic adults a drink containing 75, 371 or 963 milligrams cocoa flavanols. Plasma flavanol metabolite levels and flow mediated dilation of the brachial artery (which assesses vascular health by evaluating the ability of the artery to relax) were monitored for several hours following flavanol administration.The researchers determined that improvements in flow mediated dilation correlated with increased flavanol dose. A double-blinded trial was then conducted in which 41 patients undergoing medical treatment for type 2 diabetes were given a beverage containing 25 milligrams or 321 milligrams cocoa flavanols three times daily for thirty days. The beverages were matched for calories and other cocoa compounds such as caffeine. Flow-mediated dilation and flavanol metabolite levels were measured before treatment, 2 hours after the initial treatment, at 8 days, and at 30 days.
Although flow-mediated dilation was significantly impaired among the participants at the beginning of the study, immediate improvements were observed in the high flavanol group following flavanol consumption. By the end of the trial there was an increase in flow-mediated dilation of 30% above baseline levels among those who received the high flavanol-containing beverage, while blood pressure, heart rate and glycemic control were not affected. No significant responses were observed in the low flavanol group.
“This study is not about chocolate, and it’s not about urging those with diabetes to eat more chocolate,” Dr Kelm stated. “This research focuses on what’s at the true heart of the discussion on ‘healthy chocolate’—it’s about cocoa flavanols, the naturally occurring compounds in cocoa. While more research is needed, our results demonstrate that dietary flavanols might have an important impact as part of a healthy diet in the prevention of cardiovascular complications in diabetic patients.”
“This study is important and thought-provoking,” noted Umberto Campia, MD in an accompanying editorial. “We now have sizeable evidence that cocoa flavanols have a positive effect on the health of the arteries. This is the foundation we need for doing a much larger prospective study that looks at the effect of cocoa flavanols not just on endothelial function, but also on the risk of heart attack, stroke, and other serious forms of cardiovascular disease.”