Beta-carotene is a vitamin A precursor, which the body uses to create complete vitamin A. Carrots, sunflower sprouts, red peppers, mangos, cantaloupes, cabbage, broccoli sprouts, as well as green leafy vegetables such as spinach and kale, are foods that are rich in this nutrient. Usually, the more intense the color of the fruit or vegetable, the more beta carotene it contains. Naturally occurring beta carotene, not retinol, is the real vitamin A precursor along with its associated carotenoid factors that the body can convert into a usable form of vitamin A. Naturally occurring vitamin A and beta carotene are well documented immune boosters and cancer fighters. They are also known for their role as antioxidants.