(Sponsored by Medical Utilization Management, L.L.C.)
(Sponsored by Medical Utilization Management, L.L.C.)
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Lutein and zeaxanthine are vitamins in the vitamin A family (they are also known as xanthophylls). They are found in certain vegetables, especially dark leafy greens such as spinach and broccoli, and eggs. Lutein can be converted to zeaxanthine in the body. Different tissues have varying abilities to do so however; the macula of the eye for example relies upon diet for 50% of its zeaxanthine. Excessive amounts, unlike vitamin A, are not known to be toxic, and studies (unlike other antioxidants) linking them to increased risk of lung cancer in smokers have not been done. There are several proposed benefits to lutein and zeaxanthine in the protection against cataract, macular degeneration and early atherosclerosis. In the eye, decreased macular pigment is associated with macular thinning and increased risk of macular degeneration. Administration of lutein has been demonstrated to increase macular pigment and macular thickness. People with the highest levels of lutein and zeaxanthine in their blood are least likely to develop cataracts and macular degeneration. The usual dose in studies varies between 5 to 11.7 mg of lutein and 200 mcg of zeaxanthine. Beware: you'd need to take 25 pills a day of certain popular multivitamins "now with lutien" to achieve this dose! One way to look at the potentially protective role of substances is to measure the progression of thickness of the carotid arteries, which, when blocked, can result in stroke. Lutein supplementation was shown to block progression of intima-media thickness progression in humans and reduced lesion size 44% in apoE-null mice and 43% in LDL receptor-null mice. It also inhibited LDL-induced monocyte migration in a dose-dependent manner. The authors conclude that lutein is protective against the development of early atherosclerosis. References Dwyer JH et al. Oxygenated carotenoid lutein and progression of early atherosclerosis: the Los Angeles atherosclerosis study. Circulation 2001 Jun 19;103(24):2922-7. Ramalanjaona G. Lutein and Ocular Disease. Alternative Medicine Alert 2002 May; 5(5):54-56. Curran-Celentano J et al. Rleation between dietary intake, serum concentrations, and retinal concentrations of lutein and zeaxanthine in adults in a midwest population. Am J Clin Nutr 2001 Dec:74(6):796-802. Marees-Perlman JA et al. Lutien and zeaxanthine in the diet and serum and their relation to age-related maculopathy in the third national health and nutrition examination survey. Am J Epidemiology 2001 Mar 1;153(5):424-32. Beatty S et al. Macular pigment and risk for age-related macular degeneration in subjects from a Northers European population. Invest Ophthalmom Vis Sci 2001 Feb;42(2):439-46. Moeller SM et al. The potential role of dietary xanthophylls in catartact and age-related macular degeneration. J Am Coll Nutr 2000 Oct;19(5Suppl):522d-527S. Berendschot TT et al. Influence of lutein supplementation on macular pigment, assessed with two objective techniques. Invest Ophthalmol Vis Sci 2000 Oct;41(11):3322-6. |
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