Epicatechin ingested via cocoa products reduces blood pressure in humans: a nonlinear regression model with a Bayesian approach

Background: Four meta-analyses of randomized controlled trials (RCTs) based on the classical random-effects model showed that cocoa consumption can reduce systolic blood pressure (SBP) and diastolic blood pressure (DBP). Because epicatechin is suggested to be responsible for the treatment effect, changes in blood pressure should depend on the dose of ingested epicatechin, which may explain the between-study differences. Objective: The objective was to quantify the effect of epicatechin ingested via cocoa products on changes in SBP and DBP. Design: A nonlinear meta-regression model was chosen to investigate the impact of the epicatechin dose on changes in SBP and DBP. A Bayesian approach using Markov chain Monte Carlo methods was applied for an appropriate treatment of the nonlinearity. Results: Data from 16 RCTs on SBP and 15 RCTs on DBP were included. The close of epicatechin ingested via cocoa products influenced the changes in SBP and DBP. The asymptotic limit for the reduction was estimated at -4.6 mm Hg (95% Cl: -5.4, -3.9 mm Hg) for SBP and at -2.1 mm Hg (95% Cl: -2.7, -1.6 mm Hg) for DBP. An intake of 25 mg epicatechin/d led to a mean reduction of -4.1 mm Hg (95% Cl: -4.6, -3.6 mm Hg) in SBP and of -2.0 mm Hg (95% Cl: -2.4, -1.5 mm Hg) in DBP. Conclusions: Blood pressure reduction by consumption of cocoa products depends on the dose of ingested epicatechin, which explains most of the between-study differences in classical meta-analyses. Similar effects may be achieved by consumption of other foods that are also rich in epicatechin. Am J Clin Nutr 2012;95:1365-77.