Dark fruits, such as berries, contain compounds known as flavonoids. There are seven groups of flavonoids and one is called anthocyanidins. These are common plant pigments that give the red and blue colors to some fruits. They have been shown to work as an antioxidant, be heart protective, prevent cancer, and help with inflammation. Cherries, strawberries, blueberries, and raspberries are all full of flavonoids and make a delicious smoothie.