Biomarkers of cardiovascular disease such as systolic and diastolic blood pressure, lipid profiles, fasting glucose, insulin, triglycerides, hemoglobin A1c (HbA1c), C-reactive protein (CRP) and flow-mediated dilation (FMD) were included.
FMD improved within 2 hours after ingestion of chocolate/cocoa in 11 studies and improved after chronic intake in 11 studies. There was also a reduction in fasting insulin and serum insulin after a glucose challenge in 2 trials after chocolate or cocoa use interventions. There appeared to be no effect on fasting glucose, HbA1c and triglycerides.
Reductions of diastolic blood pressure occurred in 22 trials after chronic intake. There was only a small effect on lowering LDL (-0.07 mmol/L) and HDL (0.03 mmol/L) in 21 studies. No significant effects were seen on CRP, total cholesterol or systolic BP after acute or chronic intake. There was insufficient information or too few trials to determine effect on body weight, body mass index and waist circumference.
Commentary: It’s always comforting news when a beloved food shows health benefits. This appears to be true for chocolate, cocoa, black tea and yes, even coffee, at least up to a point. There are obviously many studies on cocoa and chocolate and individual cardiovascular parameters but this is the first systematic review and meta-analysis assessing randomized clinical trials on cocoa and chocolate in terms of vital cardiovascular risk factors. In terms of lowering insulin resistance and reduction in insulin secretion, both cocoa and chocolate show benefit. The impact on FMD appears to be clinically significant. The effect on diastolic blood pressure and marginal effects on LDL and HDL have some small potential for clinical utility. Other than caloric impact of a specific chocolate/cocoa product, this systematic review confirms the value of the judicious use of these dietary and supplemental food items. Hooray!!!
Hooper L, Kay C, Abdelhamid A, et al. Effects of chocolate, cocoa, and flavan-3-ols on cardiovascular health: a systematic review and meta-analysis of randomized trials. Am J Clin Nutr. 2012; 95(3):740-751.