Acute effect of oral flavonoid-rich dark chocolate intake on coronary circulation, as compared with non-flavonoid white chocolate, by transthoracic Doppler echocardiography in healthy adults

Abstract Purpose To assess the effects of the oral intake of flavonoid-rich dark chocolate on coronary circulation, we measured coronary flow velocity reserve (CFVR) by noninvasive transthoracic Doppler echocardiography (TTDE) in healthy adult subjects. Materials and methods The study was a randomized, single-blind design conducted for 2 weeks in 39 healthy men (mean age 29.7±3.9 years, range 23–40 years). Subjects were randomly assigned a daily intake of either flavonoid-rich dark chocolate (Meiji Black Chocolate 45 g, Meiji Seika kaisya Ltd, including cacao polyphenol 550 mg/day, 200 kcal) or non-flavonoid white chocolate (Meiji White Chocolate 35 g, Meiji Seika kaisya Ltd, including cacao polyphenol 0 mg/day, 140 kcal) as a control. CFVR was recorded by TTDE, and assessed before and after 2 weeks of intake. At the same time, we also assessed serum asymmetric dimethylarginine, 8-isoprostanes, and malondialdehyde-modified low-density lipoprotein (MDA-LDL) as markers of oxidative stress. Results Flavonoid-rich dark chocolate consumption significantly improved CFVR (3.38±0.49 before intake, 4.28±0.85 after intake; p p =0.44). All predictor variables were used as dependent variables in a multiple regression model of the incremental change in CFVR after 2 weeks of chocolate intake. Intake of dark (but not white) chocolate, MDA-LDL, triglyceride (TG) and heart rate (HR) significantly influenced the change of CFVR after 2 weeks of intake ( p Y =1.01 X 1 −0.005 X 2 −0.003 X 3 −0.017 X 4 ( Y =change in CFVR after 2 weeks of chocolate intake, X 1 =intake of dark (but not white) chocolate, X 2 =MDA-LDL, X 3 =TG, X 4 =HR). Conclusion Flavonoid-rich dark chocolate intake significantly improved coronary circulation in healthy adults, independent of changes in oxidative stress parameters, blood pressure and lipid profile, whereas non-flavonoid white chocolate had no such effects.