Chocolate and cocoa may improve heart health
MedWire News: Chocolate and cocoa consumption may have beneficial effects on cardiovascular (CV) health, research suggests.
The findings arise from a systematic review of 42 randomized controlled trials (RCTs) that assigned participants to chocolate, cocoa, or cocoa flavan-3-ols, in comparison with a control group, in acute or short-term chronic interventions.
"To our knowledge, this is the first systematic review to comprehensively assess the overall effects and validity of the available RCT data on chocolate or cocoa on a range of important CV disease risk factors," comment the authors.
Specifically, they investigated the effects on the classic modifiable Framingham risk measures: systolic and diastolic blood pressure, and total, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol. In addition, the team examined other independent predictors of CV disease risk, including fasting glucose and insulin.
A total of 1297 participants were included in the analysis, and all trials had a duration of 18 weeks or less.
Twenty-one interventions involved cocoa drinks, while dark or milk chocolate was used in 15. Cocoa supplements were used in three, solid chocolate plus cocoa drinks in two, and a whole diet including cocoa powder and chocolate, where all foods were provided, in one.
Lee Hooper (University of East Anglia, Norwich, UK) and co-investigators report marginally significant improvements in LDL (-0.07 mmol/L [-2.70 mg/dL]) and HDL (0.03 mmol/L [1.16 mg/dL]) cholesterol after the chocolate and cocoa interventions.
Insulin resistance was also significantly improved (homeostasis model assessment-insulin resistance [HOMA-IR] -0.67), due to significant reductions in serum insulin.
Flow-mediated dilation (FMD) improved after chronic and acute intakes (1.34 and 3.19%, respectively), and, the authors note, significantly improved regardless of the dose consumed. The team also observed reductions in diastolic blood pressure (-1.60 mmHg) and mean arterial pressure (-1.64 mmHg).
In analyses examining the impact of duration, effects on most outcomes were greatest in acute and in the shortest chronic studies (<3 weeks), note Hooper et al. Interestingly, however, beneficial effects on HDL cholesterol were greater in longer-term trials.
"Larger, longer-duration, and independently funded trails are required to confirm the potential cardiovascular benefits of cocoa flavan-3-ols," the team concludes in the American Journal of Clinical Nutrition.
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By Nikki Withers