Antioxidant-Rich Foods May Reduce the Risk of Macular Degeneration
]]>Age-related macular degeneration (AMD)]]> is the most common cause of irreversible blindness in developed countries. Age is the most significant risk factor. The cause of AMD is not well understood, but some researchers believe that a diet rich in antioxidants may help reduce the risk of AMD.
A new study in the December 28, 2005 issue of the Journal of the American Medical Association studied a large group of older adults, and found that those who consumed above-average intakes of beta-carotene, vitamin C, vitamin E, and zinc were less likely to develop AMD.
About the Study
Researchers in the Netherlands followed 4,170 people age 55 years or older for an average of eight years. The participants did not have AMD when the study began. At the start of the study, the participants completed a food frequency questionnaire to determine intake of the following antioxidants/antioxidant cofactors: alpha and beta carotene; beta cryptoxanthin; lutein; lycopene; vitamins A, C, and E; iron; and zinc. During the study, the participants underwent 1-2 eye examinations designed to diagnose AMD. The researchers adjusted their analyses for age, sex, body mass index (a measure of weight in relation to height), smoking status, blood pressure, cholesterol level, atherosclerosis score (a measure of fatty buildup in the arteries), and alcohol intake.
During the study, 560 (13.4%) of the participants were diagnosed with AMD. Higher vitamin E and zinc intakes were associated with a reduced risk of AMD. Having an above-average intake of the combination of vitamins C and E, beta carotene, and zinc was associated with a 35% reduced risk of AMD.
These findings are limited because nutrient intake was based on a food frequency questionnaire, which is subject to error.
How Does This Affect You?
This study suggests that diet affects vision, at least in the long-term. Increasing your intake of beta carotene, vitamin C, vitamin E, and zinc while your vision is good may help prevent AMD later. Beta carotene is found in carrots, kale, and spinach; vitamin C-rich foods include citrus fruits and juices, green peppers, broccoli, and potatoes; vitamin E can be obtained from whole grains, vegetable oil, eggs, and nuts; and high concentrations of zinc are found in meat, poultry, fish, whole grains, and dairy products. The study did not address whether taking antioxidant supplements also lowers the risk of AMD. Previous research, however, strongly suggests that an antioxidant-rich diet is superior to an antioxidant-poor diet plus supplements.
Symptoms of AMD include seeing blurred words on a page, a dark or empty area in the center of vision and distorted straight lines. If you have any of these symptoms, you should consult with an ophthalmologist, who can diagnose and treat AMD if necessary.
American Academy of Ophthalmology
Macular Degeneration Partnership
Macular degeneration. American Academy of Ophthalmology. Available at: http://www.medem.com/medlb/article_detaillb.cfm?article_ID=ZZZJ4YZNH4C&sub_cat=2013 . Accessed December 28, 2005.
van Leeuwen R, Boekhoorn S, Vingerling JR, et al. Dietary intake of antioxidants and risk of age-related macular degeneration. JAMA . 2005;294(24):3101-3107.
Last reviewed Dec 29, 2005 by ]]>Richard Glickman-Simon, MD]]>
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