Circulation. 2007
Published online before print November 5, 2007, doi: 10.1161/
CIRCULATIONAHA.107.713867

Dark Chocolate Improves Coronary Vasomotion and Reduces Platelet
Reactivity

Andreas J. Flammer MD, Frank Hermann MD, Isabella Sudano MD, PhD,
Lukas Spieker MD, Matthias Hermann MD, Karen A. Cooper MSc, PhD, Mauro
Serafini PhD, Thomas F. Lüscher MD, Frank Ruschitzka MD, Georg Noll
MD, and Roberto Corti MD*

F.R., G.N., R.C.), Cardiology, University Hospital Zurich, Zurich,
Switzerland; Nestlé Research Center (K.A.C.), Lausanne, Switzerland;
and Antioxidant Research Laboratory (M.S.), Unit of Human Nutrition
INRAN, Rome, Italy.

* To whom correspondence should be addressed. E-mail:
roberto.corti@usz.ch.

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.