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Effects of chocolate, cocoa, and flavan-3-ols on cardiovascular health: a systematic review and meta-analysis of randomized trials

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Hooper, Lee, Kay, Colin, Abdelhamid, Asmaa, Kroon, Paul A, Cohn, Jeffrey S, Rimm, Eric B, Cassidy, Aedín·2012·The American Journal of Clinical Nutrition

Abstract

Background There is substantial interest in chocolate and flavan-3-ols for the prevention of cardiovascular disease (CVD).Objective The objective was to systematically review the effects of chocolate, cocoa, and flavan-3-ols on major CVD risk factors.Design We searched Medline, EMBASE, and Cochrane databases for randomized controlled trials (RCTs) of chocolate, cocoa, or flavan-3-ols. We contacted authors for additional data and conducted duplicate assessment of study inclusion, data extraction, validity, and random-effects meta-analyses.Results We included 42 acute or short-term chronic (≤18 wk) RCTs that comprised 1297 participants. Insulin resistance (HOMA-IR: -0.67; 95% CI: -0.98, -0.36) was improved by chocolate or cocoa due to significant reductions in serum insulin. Flow-mediated dilatation (FMD) improved after chronic (1.34%; 95% CI: 1.00%, 1.68%) and acute (3.19%; 95% CI: 2.04%, 4.33%) intakes. Effects on HOMA-IR and FMD remained stable to sensitivity analyses. We observed reductions in diastolic blood pressure (BP; -1.60 mm Hg; 95% CI: -2.77, -0.43 mm Hg) and mean arterial pressure (-1.64 mm Hg; 95% CI: -3.27, -0.01 mm Hg) and marginally significant effects on LDL (-0.07 mmol/L; 95% CI: -0.13, 0.00 mmol/L) and HDL (0.03 mmol/L; 95% CI: 0.00, 0.06 mmol/L) cholesterol. Chocolate or cocoa improved FMD regardless of the dose consumed, whereas doses >50 mg epicatechin/d resulted in greater effects on systolic and diastolic BP. GRADE (Grading of Recommendations, Assessment, Development and Evaluation, a tool to assess quality of evidence and strength of recommendations) suggested low- to moderate-quality evidence of beneficial effects, with no suggestion of negative effects. The strength of evidence was lowered due to unclear reporting for allocation concealment, dropouts, missing data on outcomes, and heterogeneity in biomarker results in some studies.Conclusions We found consistent acute and chronic benefits of chocolate or cocoa on FMD and previously unreported promising effects on insulin and HOMA-IR. Larger, longer-duration, and independently funded trials are required to confirm the potential cardiovascular benefits of cocoa flavan-3-ols.

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  1. Corti R, Flammer AJ, Hollenberg NK, Luscher TF. Cocoa and car- diovascular health. Circulation 2009;119:1433-41.
  2. Review Manager (RevMan). Version 5.0. Copenhagen, Denmark: The Nordic Cochrane Centre, The Cochrane Collaboration, 2008.
  3. Hermann F, Spieker LE, Ruschitzka F, Sudano I, Hermann M, Binggeli C, Luscher TF, Riesen W, Noll G, Corti R. Dark chocolate improves endothelial and platelet function. Heart 2006;92:119-20.

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Authors
Hooper, L., Kay, C., Abdelhamid, A., Kroon, P. A., Cohn, J. S., Rimm, E. B., & Cassidy, A.
Affiliations
University of East Anglia (GB)
Corresponding author
Hooper, Lee
Venue
The American Journal of Clinical Nutrition
Publisher
Elsevier BV
Published
2012-03
Volume
95
Issue
3
Pages
740-751
ISSN
0002-9165 (ISSN-L)
OpenAlex
W2129761592
Cited by
610
References
90
Citations by year
2026: 15 · 2025: 19 · 2024: 32 · 2023: 24 · 2022: 29 · 2021: 35 · 2020: 37 · 2019: 43 · 2018: 63 · 2017: 56 · 2016: 64 · 2015: 54 · 2014: 50 · 2013: 66 · 2012: 22
FWCI
6.50
Type
journal article
Language
en
Open access
Locations
  • American Journal of Clinical Nutrition (publishedVersion)
  • PubMed (publishedVersion)
  • Digital Access to Scholarship at Harvard (DASH) (Harvard University) (submittedVersion, cc-by)
  • Research Portal (Queen's University Belfast) (submittedVersion)
  • UEA Digital Repository (University of East Anglia) (submittedVersion)
Funders
  • GlaxoSmithKline
  • Directorate for Biological Sciences
  • Biotechnology and Biological Sciences Research Council (BBS/E/F/00044434)
Topics
  • Health Sciences › Medicine › Biochemistry › Phytochemicals and Antioxidant Activities
  • Life Sciences › Agricultural and Biological Sciences › Food Science › Food Chemistry and Fat Analysis
  • Health Sciences › Medicine › Pharmacology › Coffee research and impacts
Keywords
chocolate, Theobroma cacao, flavan-3-ols, epicatechin, cardiovascular disease prevention, insulin resistance, flow-mediated dilation, endothelial function, blood pressure, LDL cholesterol, HDL cholesterol, cardiovascular risk factors, dose-response relationship, quality of evidence, GRADE, adverse effects
MeSH terms
Blood Glucose, Blood Pressure, Cacao, Candy, Cardiovascular Diseases, Cardiovascular System, Flavonoids, Humans, Insulin, Risk Factors, Reproducibility of Results, Biomarkers, Randomized Controlled Trials as Topic

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