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Lutein for Vision: One of the Hottest Topics in Ophthalmological Research
Using lutein for vision maintenance is one of the hottest topics in ophthalmological research. Lutein (pronounced LOO-teen) is a carotenoid, that is, a plant pigment, naturally occurring in dark green leafy veggies and corn, as well as in some fruits and also in egg yolks. This important phytochemical provides nutritional support to the only organs of our body directly exposed to the outside world, our skin and eyes. Lutein and other carotenoids, such as the beta-carotene found in carrots, stimulate the production of protective sebum in the skin. The most important reason for using lutein for vision is that lutein is an antioxidant, preventing damage by sunlight in the macula. Lutein filters out the highest-energy, blue-violet wavelengths of sunlight. These especially penetrating wavelengths of natural light knock electrons out of their usual positions in organic molecules to form free radicals, and the free radicals in turn interfere with the transcription of DNA into RNA necessary for making reparative proteins in the rods and cones of the macula. The light trapped by lutein is the visible blue light, not the invisible ultraviolet light associated with damage to the lens of the eye or burning of the skin. How much lutein for vision does the human body need? Recent research in Australia suggests that the eyes can benefit from about 10 mg a day, but the digestive tract can only absorb about 6 mg from any one meal. Moroever, the lutein in a plant food is not absorbed unless the meal includes at least a small amount of fat. Generally, 1 teaspoon (5 g) of fat added to the spinach or sweet corn or other vegetables eaten for lutein is enough. Lutein in the form of nutritional supplements must be formulated in oil-filled capsules. Lutein pills would not be absorbed. Lutein and its carotenoid cousin zeaxanthin interact with zinc, copper, vitamins C and E, and beta-carotene to help forestall and sometimes even completely prevent macular degeneration. All seven of these antioxidants must be supplied by diet or nutritional supplementation to lower the risk of developing this disease, especially for people who smoke or who are overweight. The chemicals in tobacco smoke destroy lutein, and fat cells can sequester it so that it does not reach the eyes. Using lutein for vision along with other nutritional supplements as "insurance" against the development of macular degeneration is an idea that was confirmed by the Age Related Eye Disease Study (AREDS), but the formula confirmed by the study is very precise. The daily dosages of the antioxidants needed for eye protection are: Where is lutein on this list? At the time of the AREDS trial, lutein was not available as a supplement, and scientists had not learned how to measure it independently of zeaxanthin. However, the later Lutein Antioxidant Supplementation Trial concluded that the best possible dosage of lutein (without zeaxanthin, because the body can make zeaxanthin out of lutein) is about 10 mg a day. This amount of lutein for vision is about 7 times more than most North Americans get from food, but it is also more than the body can absorb from any one meal or one dose of the supplement. This means you should take your lutein supplements in at least two doses at different times during the day. |