Orange carrots contain beta carotene, with some alpha-carotene, both of which are orange pigments. These type of carrots are high in Vitamin A that is essential for the well-being of healthy eyes.
Yellow carrots contain xanthophylls and lutene, pigments similar to beta carotene, which help develop healthy eyes and may prevent lung and other cancers and reduce the risk of hardening of the arteries.
Red carrots contain lycopene, (another form of carotene) a pigment also found in tomatoes and watermelon. It helps to reduce risk of macular degeneration, serum lipid oxidation and also helps prevent to heart disease and a wide variety of cancers including prostate cancer.
White carrots lack pigment, but may contain other health-promoting substances called phytochemicals, natural bioactive compounds found in plant foods that work with nutrients and dietary fibre to protect against disease.
Purple carrots have even more beta carotene than their orange cousins. These types of carrots are orange from inside. The anthocyanin pigment in it acts as a powerful antioxidant.
Black carrots also contain anthocyanin like the purple carrots, and belong to flavonoid family. Flavonoids are currently under investigation as anticancer compounds and free radical scavengers in living systems, as well as inhibitors of LDL (the bad) cholesterol.