INTRODUCTION
In vitro data suggest that cocoa and chocolate might protect the vascular endothelium by improving nitric oxide (NO) availability (1). It was recently shown in 2 different studies in healthy volunteers (2, 3) that the cocoa-related increase in NO availability is due to flavanols, ie, a subclass of flavonoids mainly represented by epicatechin and catechin and their oligomers (procyanidins) (4). In keeping with this, polyphenol-rich dark chocolate but not polyphenol-free white chocolate bars significantly reduced blood pressure in elderly patients with isolated systolichypertension (5). Because insulin-mediated increases in NO availability significantly improve insulin-mediated glucose uptake in healthy persons (6, 7), we hypothesized that polyphenolrich dark chocolate was able to improve insulin sensitivity and decrease blood
pressure in healthy subjects. Therefore, we compared the effects of 2 different kinds of chocolate bars, ie, either with a high or a low polyphenol content, on the glucose and
insulin responses to an oral glucose challenge and on blood pressure in relatively young subjects without metabolic diseases and cardiovascular disease risk factors.