Radicchio, like other chicory class of vegetables, is very low in calories. 100 g fresh leaves carry just 23 calories.
Its leaves are an excellent source of phenolic flavonoid antioxidants such as zea-xanthin, and lutein. 100 grams leaves provide 8832 µg of these pigments. Zea-xanthin is a xanthophyll category of flavonoid carotenoid (yellow pigment) which concentrates mainly in the central part of retina in humans. Together with lutein, it helps protect eyes from age-related macular disease (ARMD) by filtering harmful ultra-violet rays.