Cocoa is derived from the cacao bean, which contains one of the highest concentrations of flavanols of any food. Flavanols are the specific class of polyphenol responsible for cocoa's health effects. They are found in the cacao solids. As cocoa percentage in chocolate decreases, so does flavanol content. Milk chocolate and white chocolate contain negligible amounts. Dark chocolate at 70 percent or above retains meaningful flavanol content, and 85 percent or above is preferable.
Cardiovascular Effects
A meta-analysis of 24 randomised controlled trials found that cocoa flavanol consumption significantly improved endothelial function, reduced blood pressure, reduced LDL oxidation, and improved insulin sensitivity. The COSMOS Heart Study, a large randomised trial of 21,442 participants published in the American Journal of Clinical Nutrition, found that cocoa flavanol supplementation was associated with a 27 percent reduction in cardiovascular mortality over 3.6 years of follow-up.
Cognitive Effects
Cocoa flavanols improve cerebral blood flow and activate BDNF pathways in the hippocampus. A large randomised trial, CoCoA, found that 8 weeks of high-flavanol cocoa improved memory function and processing speed in healthy older adults. The effect was dose-dependent and correlates with increases in cerebral blood flow measured by MRI.
- Choose dark chocolate at 85 percent cocoa or above for maximum flavanol content
- A 30-gram portion daily provides meaningful flavanol intake without excessive calorie or saturated fat load
- Store in a cool, dry place; heat degrades flavanols
- Avoid Dutch-processed cocoa powder as alkalisation destroys most of the flavanols