ARS | Publication request: Cocoa Reduces Blood Pressure and Insulin Resistance and Improves Endothelium-Dependent Vasodilation in Hypertensives

Submitted to: Hypertension
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 13, 2005
Publication Date: August 1, 2005
Citation: Grassi, D., Necozione, S., Lippi, C., Croce, G., Valeri, L., Pasqualetti, P., Desideri, G., Blumberg, J.B., Ferri, C. 2005. Cocoa reduces blood pressure and insulin resistance and improves endothelium-dependent vasodilation in hypertensives. Hypertension. 46(2):398-405.

Interpretive Summary: Studies of large population groups suggest dietary flavonoids decrease the risk of death from coronary heart disease and stroke. Flavonoid-rich foods include fruits and vegetables as well as tea, red wine, and chocolate. The high flavonoid content, particularly in flavanols and their procyanidin oligomers, of these foods may contribute to some of their putative cardiovascular benefits. The antioxidant protection afforded by flavonoids in blood vessels may reduce the risk for atherosclerosis by modulating the action of nitric oxide, an endogenous vasodilating compound. As cocoa flavonoids have been found to be potent modulators of nitric oxide, we examined the effect of flavanol-rich dark chocolate and flavanol-empty white chocolate on blood pressure in people with essential hypertension in a randomized, cross-over clinical trial. We found the dark chocolate intervention, but not the white chocolate intervention decreased blood pressure and serum LDL ("bad") cholesterol, improved a measure of blood vessel relaxation, and ameliorated insulin sensitivity. These results suggest that, while balancing total calorie intake, flavanols from cocoa products may provide some cardiovascular benefit if included as part of a healthy diet for people with essential hypertension.

Technical Abstract: Consumption of flavanol-rich dark chocolate (DC) has been shown to decrease blood pressure (BP) and insulin resistance in healthy subjects, suggesting similar benefits in patients with essential hypertension (EH). Therefore, we tested the effect of DC on 24-hour ambulatory BP, flow-mediated dilation (FMD), and oral glucose tolerance tests (OGTTs) in patients with EH. After a 7-day chocolate-free run-in phase, 20 never-treated, grade I patients with EH (10 males; 43.7 7.8 years) were randomized to receive either 100 g per day DC (containing 88 mg flavanols) or 90 g per day flavanol-free white chocolate (WC) in an isocaloric manner for 15 days. After a second 7-day chocolate-free period, patients were crossed over to the other treatment. Noninvasive 24-hour ambulatory BP, FMD, OGTT, serum cholesterol, and markers of vascular inflammation were evaluated at the end of each treatment. The homeostasis model assessment of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), and insulin sensitivity index (ISI) were calculated from OGTT values. Ambulatory BP decreased after DC (24-hour systolic BP 11.9 7.7 mm Hg, P 0.0001; 24-hour diastolic BP 8.5 5.0 mm Hg, P 0.0001) but not WC. DC but not WC decreased HOMA-IR (P 0.0001), but it improved QUICKI, ISI, and FMD. DC also decreased serum LDL cholesterol (from 3.4 0.5 to 3.0 0.6 mmol/L; P 0.05). In summary, DC decreased BP and serum LDL cholesterol, improved FMD, and ameliorated insulin sensitivity in hypertensives. These results suggest that, while balancing total calorie intake, flavanols from cocoa products may provide some cardiovascular benefit if included as part of a healthy diet for patients with EH.