Age-related macular degeneration (AMD) is the leading cause of vision loss in the world, and the number of people expected to have AMD in the United States is rising because of the aging population.
Previous studies have shown that people who consume more carotenoids, antioxidants, and omega-3 fatty acids have a lower risk of developing AMD. An extensive literature review (347 articles) was done of studies of benefits and risks of these supplements for AMD. Significant benefits were seen in the two largest randomized controlled trials only. The Age Related Eye Disease Study (AREDS) followed 3,640 patients for 7 years. This study used 500 mg vitamin C, 400 IU vitamin E, 15 mg beta carotene, 80 mg zinc oxide and 2 mg copper oxide with the more severely involved patients. The longer-term studies may have shown more benefits because AMD progresses slowly.
There were some risks found in the antioxidant studies. “Beta-carotene may be associated with an increased risk of lung cancer among active smokers.” There was no increased risk among former smokers or nonsmokers. However, there was an increased risk of mortality among people taking over 400 IU daily of vitamin E, with an increased risk of prostate cancer and congestive heart failure. People on 80 mg zinc oxide and 2 mg copper had more urinary tract infections than those who were not.
AREDS II was designed to follow patients for 5 years regarding benefits and risks to AMD patients of taking lutein, zeaxanthin, and omega-3 fatty acids DHA and EPA. The study was designed to evaluate lowering or eliminating vitamin C, vitamin E, beta carotene, zinc, and copper from the original formula.
CONCLUSION: There is some evidence for reduced vision loss from AMD among people with more severe AMD taking carotenoids, zinc, and antioxidants. “Current literature does not support the use of these supplements for patients with mild AMD.” Beta-carotene may increase the risk of lung cancer in active smokers, and high doses of vitamin E may pose some risk of prostate cancer and congestive heart failure.