Objectives In patients with coronary artery disease (CAD) medically managed according to currently accepted guidelines, we tested whether a 1-month dietary intervention with flavanol-containing cocoa leads to an improvement of endothelial dysfunction and whether this is associated with an enhanced number and function of circulating angiogenic cells (CACs).

Background Dietary flavanols can improve endothelial dysfunction. The CACs, also termed endothelial progenitor cells, are critical for vascular repair and maintenance of endothelial function.

Methods In a randomized, controlled, double-masked, cross-over trial, 16 CAD patients (64 ± 3 years of age) received a dietary high-flavanol intervention (HiFI [375 mg]) and a macronutrient- and micronutrient-matched low-flavanol intervention (LoFI [9 mg]) twice daily in random order over 30 days.

Results Endothelium-dependent vasomotor function, as measured by flow-mediated vasodilation of the brachial artery, improved by 47% in the HiFI period compared with the LoFI period. After HiFI, the number of CD34+/KDR+-CACs, as measured by flow cytometry, increased 2.2-fold as compared with after LoFI. The CAC functions, as measured by the capacity to survive, differentiate, proliferate, and to migrate were not different between the groups. The HiFI led to a decrease in systolic blood pressure (mean change over LoFI: −4.2 ± 2.7 mm Hg), and increase in plasma nitrite level (mean change over LoFI: 74 ± 32 nM). Applying a mixed-effects linear regression model, the results demonstrated a significant increase in flow-mediated vasodilation and a decrease in systolic blood pressure with increasing levels of CD34+/KDR+-CACs.

Conclusions Sustained improvements in endothelial dysfunction by regular dietary intake of flavanols are associated with mobilization of functional CACs. (Effect of Cocoa Flavanols on Vascular Function in Optimally Treated Coronary Artery Disease Patients: Interaction Between Endothelial Progenitor Cells, Reactivity of Micro- and Macrocirculation; NCT00553774).