High levels of antioxidants and zinc significantly reduce the risk of advanced age-related macular degeneration (AMD) and its associated vision loss, US researchers report this week. Scientists found that people at high risk of developing advanced stages of AMD, a leading cause of vision loss, lowered their risk by about 25 percent when treated with a high-dose combination of vitamin C, vitamin E, beta-carotene, and zinc. In the same high risk group -- which includes people with intermediate AMD, or advanced AMD in one eye but not the other eye -- the nutrients reduced the risk of vision loss caused by advanced AMD by about 19 percent. For those study participants who had either no AMD or early AMD, the nutrients did not provide an apparent benefit. . The clinical trial, called the Age-Related Eye Disease Study (AREDS), was sponsored in the US by the National Eye Institute (NEI), one of the Federal government's National Institutes of Health. "This is an exciting discovery because, for people at high risk for developing advanced AMD, these nutrients are the first effective treatment to slow the progression of the disease,"said Paul A. Sieving, M.D., Ph.D., director of the NEI. "AMD is a leading cause of visual impairment and blindness in Americans 65 years of age and older. Currently, treatment for advanced AMD is quite limited." The nutrients evaluated by the AREDS researchers contained 500 milligrams of vitamin C; 400 international units of vitamin E; 15 milligrams of beta-carotene; 80 milligrams of zinc as zinc oxide; and two milligrams of copper as cupric oxide (Copper was added to the AREDS formulations containing zinc to prevent copper deficiency, which may be associated with high levels of zinc supplementation). The Age-Related Eye Disease Study involved 4,757 participants, 55-80 years of age, in 11 clinical centres nationwide. Participants in the study were given one of four treatments: zinc alone; antioxidants alone; a combination of antioxidants and zinc; or a placebo, a harmless substance that has no medical effect. The benefits of the nutrients were seen only in people who began the study at high risk for developing advanced AMD -- those with intermediate AMD, and those with advanced AMD in one eye only. In this group, those taking "antioxidants plus zinc" had the lowest risk of developing advanced stages of AMD and its accompanying visual loss. Those in the "zinc alone" or "antioxidant alone" groups also reduced their risk of developing advanced AMD, but at more moderate rates compared to the "antioxidants plus zinc" group. Those in the placebo group had the highest risk of developing advanced AMD. The full findings from this nationwide clinical trial are reported in the October 2001 issue of Archives of Ophthalmology.