Acute Hemodynamic Effects of Cocoa Polyphenols in Subjects With Hypertension and Optimal Blood Pressure

Summary

Intake of cocoa-containing foods has been found to lower blood pressure (BP) in several clinical trials. It is supposed that the cocoa polyphenols represent the active principle, lowering BP by increasing the formation of vasodilative nitric oxide. However, direct evidence for this assumption from controlled clinical studies is lacking. Moreover, in hypertensive subjects vascular dilation appears to be impaired due to endothelial dysfunction and vascular smooth muscle remodeling, but it is unclear whether the BP response to cocoa phenols differs between subjects with high blood pressure and optimal blood pressure.

The investigators hypothesized that (1) intake of cocoa phenols cause a dose-dependent, acute elevation of circulating bioactive NO levels and a reduction in BP, and that (2) the NO elevation and BP reduction are impaired in patients with hypertension.

To test this hypothesis, the investigators will conduct a prospective, randomized, placebo-controlled, double-blind, sample size-calculated, three-period crossover study with pre-planned statistical analysis and trial monitoring, in which cocoa phenols will be orally administered to subjects with mild essential hypertension or subjects with optimal blood pressure. The effects on blood pressure, heart rate, arterial function and plasma levels of cocoa phenols, circulating bioactive nitric oxide, and plasma markers of oxidative stress will be evaluated. After a 7-day cocoa-free run-in period and a 12-hour overnight fast, 48 subjects (24 with hypertension and 24 sex-, and age (+/- 2yrs)-matched subjects with optimal blood pressure) will receive either a single dose of 1000 mg cocoa polyphenols, 250 mg cocoa phenols or placebo (in capsules of equal form and weight). Each intervention will be followed by a 7-day cocoa-free washout period before cross-over to the subsequent intervention. Subjects will be allocated to the intervention sequence by permuted block randomization (i.e. permuted blocks of 2 subjects with high BP and 2 subjects with optimal BP each, are assigned to permutations of the tree interventions). Measurements of hemodynamic and plasma parameters will be performed directly before and 30, 60, 90, 120, 180, 300, and 480 min after capsule administration. Included subjects will be counseled to maintain their usual diet and physical activity and to abstain from all cocoa products during the study. Analysis of the data will be performed on an intention-to-treat basis.

Conditions

• Hypertension

Interventions

DIETARY_SUPPLEMENT

cocoa polyphenols

Oral administration of capsules with 1000 mg polyphenols, 250 mg polyphenols or placebo

DIETARY_SUPPLEMENT

cocoa polyphenols

Oral administration of capsules with 1000 mg polyphenols, 250 mg polyphenols or placebo

Sponsors & Collaborators

• University of Cologne

  lead OTHER

Principal Investigators

• Dirk Taubert, MD, PhD · University of Cologne

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Model

CROSSOVER

Eligibility

Min Age

50 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2007-10-31

Primary Completion

2008-09-30

Countries

• Germany

Study Locations