High flavanol cocoa and dark chocolate enhance vasodilation and reduce arterial stiffness

Abstract

Consumption of cocoa and dark chocolate has been shown to increase flow mediated dilation (FMD), but less is known about its effects on arterial compliance. We examined whether vascular effects could be sustained over 4 weeks. We enrolled 30 middle‐aged, overweight adults in a randomized, placebo‐controlled, crossover study. At baseline and end of each treatment, we measured brachial artery diameter and augmentation index (AI), a measure of arterial stiffness. During the active treatment, participants consumed 37 g/d dark chocolate and a sugar free cocoa beverage (CHOC) [total flavanols (TF) = 332mg/d] in place of a snack. Color‐matched controls included a low‐flavanol chocolate bar and a sugar‐free, non‐cocoa beverage (CONT) (TF = 0 mg/d). Treatments were roughly equivalent in total calories and fatty acid content. After CHOC treatment, artery diameter was significantly increased under resting conditions (+0.2 mm) and at the post‐deflation peak (+0.2 mm). CHOC significantly reduced AI (−1.0 ± 2.5 vs. 6.1 ± 2.5, CHOC vs. CONT, respectively). FMD and body weight did not differ across treatments. These results indicate that cocoa and dark chocolate increase arterial diameter, primarily through a reduction in vascular stiffness. Future work should examine dose‐response relationships to determine the threshold polyphenol intake to produce optimal vascular responses. Funded by: The Hershey Company