Effects of Cocoa Intake on Blood Pressure in Elderly Individuals With Mild Hypertension
Status:
Completed
Trial end date:
2005-05-01
Target enrollment:
Participant gender:
Summary
Regular intake of cocoa-containing foods is linked to a considerably lower cardiovascular and
all-cause mortality in observational studies. Short-term intervention studies indicate that
high doses of cocoa improve endothelial function and reduce blood pressure (BP), but the
clinical impact of long-term intake of small dietary amounts of cocoa on BP and the
underlying BP lowering mechanisms are unclear. We hypothesized that cocoa consumption lowers
blood pressure by augmentation of the circulating vasodilative nitric oxide (NO) pool due to
the action of the cocoa polyphenols at the vascular endothelium.
To test this hypothesis, we will conduct a randomized single-blind, parallel group study in
subjects with mild essential hypertension to evaluate the effects of polyphenol-rich dark
chocolate versus polyphenol-free white chocolate on blood pressure and plasma levels of cocoa
phenols, circulating bioactive nitric oxide, and plasma markers of oxidative stress. After a
7 day cocoa-free run-in period, 44 subjects will be 1:1 randomized to receive over 18 weeks
daily doses of either dark chocolate (6.3 g per day with a total of 30 mg of polyphenols and
30 kcal) or polyphenol free white chocolate (5.6 g per day with 30 kcal, containing similar
amounts of macronutrients, electrolytes and vitamins). Subjects will be counseled to maintain
an isocaloric diet and to abstain from other cocoa products during the study. Blood pressure
and plasma parameters will be assessed in each subject after the run-in period and after 6,
12, and 18 weeks of treatment.