In animals and humans, carotenes function as antioxidants and some like beta-carotene can be converted to vitamin A in the body. Over 600 different carotene compounds have been identified and many have promising cancer preventing effects. Interestingly, the best benefits appear to come from food sources of the carotenes, rather than from isolated compounds in supplement form. Deficiency of lutein increases the risk of cataracts and macular degeneration. Food Sources Alpha, beta and gamma carotene are found in large amounts in leafy greens, carrots, sweet potatoes, squash, apricots and yams.
Lycopenes are high in tomatoes, carrots, green peppers, apricots and pink grapefruit.
Lutein is high in leafy greens, corn, carrots, tomatoes and fruits. There is no RDA for carotenes. For vegetarians, beta-carotene will be converted to supply vitamin A in the body. The amount of beta-carotene needed to supply the RDA of vitamin A in an adult is 5 mg or 8300 IU per day. Since the carotenes work together, the best way to get good amounts of all of them is to consume plenty of fresh vegetables and fruits, especially leafy greens, dark orange vegetables and fruits and tomatoes.