Does Chocolate Lower Blood Pressure?

There has been so much attention paid lately to the effect of cocoa on blood pressure. These studies mostly seem to show a relationship between the consumption of cocoa flavanols and blood pressure. All except for one US study. Now, in a study with funding from Mars (maker of CocoaPro(TM) and CocoaVia(TM) products), researchers observed "blood pressure, heart rate, and glycemic control were unaffected", even at levels of 963mg of cocoa flavanol per day.

That would seem to be a disappointing result..., and you might wonder why the researchers would go to the trouble and expense to get it published. But actually, in this 10-subject "feasibility" study, the diabetic subjects experienced 30% improvement in Flow-Mediated Dialation. This means their arteries were more able to relax, according to a press release from Mars. And any improvement in blood vessel function is good news for diabetics, who are at high risk for heart attacks and strokes. And, according to a Science Daily Article, "blood vessel function went from severely impaired to normal." Which is an enormous improvement.

But why, since cocoa flavanols have been shown to cause blood vessels to relax, doesn't this study show improvements in blood pressure? And why have earlier studies (such as those I mentioned here) shown significant improvements in blood pressure? And why are the people of the autonomous Kuna comarcas of Panama apparantly immune to high blood pressure? Is it the 100% cacao beverage they drink all day long, or something else?