The Consumer Advice Center in North Rhine-Westphalia, Germany, recommends eating berries and grapes alone. The center explained that flavanols are biologically active compounds that are of great benefit to health, as they have an antioxidant effect.
Flavanols only work in the body if they do not combine with a specific enzyme, namely “polyphenol oxidase” (PPO), which is found in 18 types of fruits and vegetables such as apples and bananas, as well as green tea.