Dark chocolate improves coronary vasomotion and reduces platelet reactivity

Circulation. 2007 Nov 20;116(21):2376-82. doi: 10.1161/CIRCULATIONAHA.107.713867. Epub 2007 Nov 5.


Background: Dark chocolate has potent antioxidant properties. Coronary atherosclerosis is promoted by impaired endothelial function and increased platelet activation. Traditional risk factors, high oxidative stress, and reduced antioxidant defenses play a crucial role in the pathogenesis of atherosclerosis, particularly in transplanted hearts. Thus, flavonoid-rich dark chocolate holds the potential to have a beneficial impact on graft atherosclerosis.

Methods and results: We assessed the effect of flavonoid-rich dark chocolate compared with cocoa-free control chocolate on coronary vascular and platelet function in 22 heart transplant recipients in a double-blind, randomized study. Coronary vasomotion was assessed with quantitative coronary angiography and cold pressor testing before and 2 hours after ingestion of 40 g of dark (70% cocoa) chocolate or control chocolate, respectively. Two hours after ingestion of flavonoid-rich dark chocolate, coronary artery diameter was increased significantly (from 2.36+/-0.51 to 2.51+/-0.59 mm, P<0.01), whereas it remained unchanged after control chocolate. Endothelium-dependent coronary vasomotion improved significantly after dark chocolate (4.5+/-11.4% versus -4.3+/-11.7% in the placebo group, P=0.01). Platelet adhesion decreased from 4.9+/-1.1% to 3.8+/-0.8% (P=0.04) in the dark chocolate group but remained unchanged in the control group.

Conclusions: Dark chocolate induces coronary vasodilation, improves coronary vascular function, and decreases platelet adhesion 2 hours after consumption. These immediate beneficial effects were paralleled by a significant reduction of serum oxidative stress and were positively correlated with changes in serum epicatechin concentration.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blood Platelets / drug effects*
  • Blood Platelets / physiology
  • Cacao*
  • Candy*
  • Coronary Angiography / methods
  • Coronary Vessels / drug effects*
  • Coronary Vessels / physiology
  • Double-Blind Method
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / physiology
  • Flavonoids / administration & dosage
  • Heart Transplantation / methods
  • Humans
  • Platelet Adhesiveness / drug effects*
  • Platelet Adhesiveness / physiology
  • Vasodilation / drug effects*
  • Vasodilation / physiology
  • Vasomotor System / drug effects
  • Vasomotor System / physiopathology


  • Flavonoids