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)