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| Lutein is a fat-soluble antioxidant carotenoid biochemical that is found in green leafy vegetables such as spinach, kale, collard greens, romaine lettuce, leeks and peas. It is the primary carotenoid in the central area of the retina called the macula. Lutein and, to a lesser extent, zeaxanthin, a carotenoid found in leafy vegetables, corn and egg yokes, act to filter and shield harmful blue light from the eye and protect against age-related (dry) macular degeneration (AMD), the leading cause of blindness in people over 55.
The structural components of the macula are very delicate and can be readily damaged by highly energetic blue light waves. Lutein and zeaxanthin are yellow pigments that asborb this blue light and help to protect the cellular structures of the retina from damage. Too much damage can cause loss of vision. Unfortunately, absorption of high energy blue light can also destroy both lutein and zeaxanthin. Therefore, these protective pigments must be constantly replaced in the retina.
Much research has been done on the relationship between lutein and age-related macular degeneration. In 1994, Dr. Johanna Seddon of Harvard University published a study in the Journal of the American Medical Association that found that an intake of 6 mg per day of lutein led to a 57 percent lower prevalence of AMD. In 1995, Dr. Max Snodderly of the Schepens Eye Institute of Harvard University found that blue light is particularly damaging to the eye, and can cause photo-oxidation in the macular region. This process in turn leads to lipid peroxidation, which is highly toxic to the retina. He concluded that lutein and zeaxanthin prevent blue light damage by absorbing blue light and inhibiting photo-oxidation.
In 1996, Researchers at Florida International University examined the levels of lutein in cadavers of people with AMD versus those without. Levels of lutein in the macular region were lower in the people with AMD. Also in 1996, researchers at the DVA Medical Center-North Chicago published an article in the Journal of the American Optometric Association that examined the effects of antioxidant intake upon patients who had already developed AMD. They found that antioxidant supplements may have helped to prevent progression of AMD. This study provided evidence that AMD was a nutrition-responsive disease.
In 1997, Researchers at Florida International University gave subjects 30 mg of lutein per day for a period of about five months. These subjects increased the amount of lutein in the macular region of the retina by 20 to 40 percent, resulting in 30 to 40 percent lower levels of blue light striking the macular photoreceptors and other cells in the macular region. In 1998, Dr. Billy R. Hammond measured the macular pigment density of 27 older (aged 60 84 years) and 10 younger (aged 24 36 years) subjects and determined their visual sensitivity. The results showed that older subjects with high levels of lutein and zeaxanthin had about the same visual sensitivity as younger subjects. Conversely, older subjects with low lutein and zeaxanthin in their macula showed lower visual sensitivity. More recent studies have corroborated the above findings.
Two modifiable environmental factors contribute to AMD: smoking and bright sunlight. Smoking increases the risk of AMD two to four times. In bright sunlight, more blue light waves are present to cause damage. Ultraviolet (UV) protectant sunglasses reduce this risk. In a 1998 review published by the Journal of the American Optometric Association, a study by Dr. Pratt showed that AMD incidence may be significantly reduced by quitting smoking, by protecting the retina from direct sunlight, and by consuming green leafy vegetables rich in lutein.
Most of the research data taken from:
Lutein Information Bureau
http://www.luteininfo.com
(c)Copyright 2002 Chip Engelmann
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