Chemicals in cocoa can boost memory abilities in older people, a new study suggests. US researchers found flavanols – plant chemicals that are abundant in cocoa beans – improved performance in a list-learning task for people aged between 50 and 75. Flavanols belong to a group of compounds called polyphenols, which are also abundant in red wine, tea, olive oil, onions, leeks, broccoli and blueberries. Flavanols are 'bioactive food constituents' ...