BIRMINGHAM, United Kingdom — As winter arrives, hot tea and cocoa naturally become popular drink choices with a lot of people. A new study finds drinking cocoa is not just the popular choice, it may also be the “smart” choice as well. Researchers at the University of Birmingham say consuming flavanol-rich products, such as cocoa, increases one’s mental performance. Flavanols are a group of molecules which occur naturally in fruits and vegetables. They’re a member of the plant flavonoid family and are common in cocoa, grapes, apples, tea, berries, and even wine. While previous studies reveal these molecules can improve...