Carotenoids are the primary pigments found in red, yellow and orange colored plants (fruits and vegetables). They are synthesized by plants in the chromoplast, an organelle different from the chloroplast, which synthesizes chlorophyll.
Carotenoids are lipid-soluble antioxidants that are involved in the normal maintenance of mucus membranes in the eye.
Beta-carotene, lycopene and lutein are the most important of the carotenoids and in addition to supporting the eye, they are also believed to prevent cancer and delay the process of aging.
Consuming foods rich in carotenoids can lower the risk of colon and bladder cancer.
Carotenoids are found in apricots, carrots, mangoes, pumpkins, sweet potatoes and of course tomatoes. There are hundreds of carotenoids in the plant world with two major divisions. Carotenes and xanthophylls Xanthophylls contain molecular oxygen whereas carotenes do not.
Carotenoids range in color from pale yellow to bright red. Their actual color is based on its chemical structure and which waves are reflected and absorbed.
Xanthophylls because of the presence of molecular oxygen are often yellow Lutein is classified as an xanthophyll.
Lycopene and beta-carotene, lack molecular oxygen in its structure and are therefore carotenes. They are orange to red in color.
Beta-carotene is the best-known carotene due to its importance as a vitamin A precursor. There are over 600 carotenoid pigments documented and over 50 that can be metabolized to active vitamin A. Another one of Nature’s libraries.
Lycopene is a carotenoid and is the principal pigment found in bright red fruits (tomatoes), spices (paprika) and pink grapefruit. Structurally, lycopene resembles but is a much more powerful antioxidant than beta-carotene. Lycopene however lacks vitamin A activity.
Lycopene is considered cancer-preventive. Once lycopene enters the blood it preferentially targets the prostate gland, lungs and eye. Its antioxidant activity is thought to prevent prostate cancer.
Lutein is another carotenoid found in pigmented plants. Dark green, leafy vegetables contain a high concentration of this pigment. Lutein is important for eyesight and is preferentially deposited in the macula and the rods of the retina.
Lutein is a yellow pigment that absorbs blue light and prevents excessive oxidative damage to the eye.
Beta-carotene is a precursor of the active form of vitamin A and prevents lipid peroxidation. Beta-carotene lacks the toxicity associated with vitamin A.
Beta-carotene is an excellent quencher of singlet oxygen free radicals and is primarily carried in the blood by LDL. Beta-carotene is believed to be a safe supplement and certainly supplements containing 10-12 mg are completely safe. Nevertheless, there have been reports that high doses of beta-carotene among smokers increased their incidence of contracting lung cancer.