02.20.09
Indication: Blood pressure and insulin resistance
Source: Am J Clin Nutr, December 2008;88(6):1685-96.
Research: The objective of this study was to test the hypothesis that consumption of cocoa may simultaneously lower blood pressure, improve endothelial dysfunction and ameliorate insulin resistance in subjects with essential hypertension. Researchers conducted a randomized, placebo-controlled, double-blind, crossover trial of a flavanol-rich cocoa drink (150 mL twice a day, approximately 900 mg flavanols/d) in 20 individuals with essential hypertension. Antihypertensive medications were discontinued before study enrollment. After a 7-day cocoa-free run-in period, cocoa or flavanol-poor placebo (approximately 28 mg flavanols/day) treatment for 2 weeks was followed by a 1-week washout and then crossover to the other treatment arm. Blood pressure was measured thrice weekly.
Results: Cocoa treatment for 2 weeks increased insulin-stimulated changes in brachial artery diameter when compared with placebo. Nevertheless, cocoa treatment did not significantly reduce blood pressure or improve insulin resistance, and had no significant effects on skeletal muscle capillary recruitment, circulating plasma concentrations of adipocytokines, or endothelial adhesion molecules. Therefore, researchers believe daily consumption of flavanol-rich cocoa for 2 weeks is not sufficient to reduce blood pressure or improve insulin resistance in human subjects with essential hypertension.