| Carotene is a precursor to vitamin A, which means that it turns into vitamin A in your body. In fact, carotene's scientific name is Provitamin A.
Carotene can be found in most yellow, orange, or red fruits and vegetables, among other foods like seaweed.
Beta-carotene is the most effective and possibly the best-known form of carotene; it also serves as an antioxidant. Signs of a deficiency include deteriorating eyesight, oversensitivity to light, irritated eyes, and various skin disorders.
Go Ask Alice (the advice column, not the book) notes that "beta-carotene along with other phytochemicals (nutrients of plant origin) may be effective against macular degeneration (an eye disease causing blindness), prostate, and other cancers." (http://www.goaskalice.columbia.edu/0926.html) | 
