Abstract 12428: Caffeine Contained in a Cup of Coffee Ameliorates Microvascular Endothelial Function in Healthy Subjects
Background: Coffee is the most widely consumed beverage in the world. Coffee contains a variety of pharmacological ingredients, including caffeine, and it has long been argued whether coffee drinking is beneficial or harmful for cardiovascular disease. Recent epidemiological studies have settled this argument, and indicated that coffee consumption is associated with reduced mortality of cardiovascular disease (NEJM 2012). However, its precise mechanisms remain to be clarified. Although microvessels regulate vascular resistance and tissue blood flow, and play an essential role in the circulatory system, no study has ever addressed the effect of coffee on microvascular function. Thus, in this study, we tested our hypothesis that caffeine contained in a cup of coffee improves microvascular endothelial function in healthy subjects.
Methods and Results: A double-blind, placebo-controlled, crossover study was performed in 27 healthy volunteers (13 men and 14 women; 22-30 years old). A cup of either caffeinated or decaffeinated coffee was drunk by the subjects, and reactive hyperemia of finger blood flow was assessed by laser Doppler flowmetry. In an interval of more than 2 days, the same experimental protocol was repeated with another coffee. Caffeinated coffee significantly elevated blood pressure and decreased finger blood flow as compared with decaffeinated coffee (each P≤0.05). There was no significant difference in heart rate between caffeinated and decaffeinated coffee. Importantly, caffeinated coffee significantly enhanced post-occlusive reactive hyperemia of finger blood flow, an index of microvascular endothelial function, compared with decaffeinated coffee (P≤0.05). Plasma levels of epinephrine or norepinephrine that could affect endothelial function did not significantly differ in caffeinated and decaffeinated coffee.
Conclusions: Our double-blind, placebo-controlled, crossover study demonstrated, for the first time, that caffeine contained in a cup of coffee ameliorates microvascular endothelial function in healthy individuals. These findings may explain, at least in part, the association of coffee consumption with reduced mortality of cardiovascular disease.
- © 2013 by American Heart Association, Inc.