Older adults with high levels of beta-carotene, vitamins C, D and E, lutein, zeaxanthin, zinc and omega-3, had healthier eyesight than those who had low levels of these nutrients, according to a new review of five large studies covering 21,485 participants, aged 50 to 80, in over a dozen research centers around the world, from 1988 through 2005.
In the U.S. National Eye Institute Age-Related Eye Disease Study (AREDS), participants with moderate to high risk of losing eyesight—a condition known as age-related macular degeneration, or AMD—who took a daily combination of 15 mg of beta-carotene, 500 mg of vitamin C, 400 IU of vitamin E, plus 80 mg of zinc oxide with 2 mg of copper (cupric) oxide, had an average 22% lower risk of developing AMD than those who did not take these nutrients. The placebo group had the highest risk of AMD. Doctors included the 2 mg of copper to protect against copper deficiency, which can occur when zinc levels are high.
Participants in the Netherlands-based Rotterdam Study who had high levels of beta-carotene, vitamins C and E, and zinc had substantially lower risk for AMD than those with low levels.
In the 20th report of AREDS, participants who had high levels of the omega-3 docosahexaenoic acid (DHA) were less likely to develop the most serious type of AMD, called “wet” AMD, where abnormal blood vessels form in the eye.
In two studies of participants with AMD, the disease progressed more slowly for those who had a high level of lutein or zeaxanthin compared to those with low levels [Carotenoids in Age-Related Eye Disease Study (CAREDS) and the Pathologies Oculaires Liees a l’Age (POLA)].
In the National Health and Nutrition Examination Survey (NHANES), those with the highest levels of vitamin D had 40% less risk of developing AMD than those who had the lowest levels.