Age-related macular degeneration, or AMD, is the leading cause of blindness in people over 60 and affects more than 10 million people, according to the University of Maryland Medical Center. Recent research into the effect of nutritional vitamin supplements on AMD have found some benefit for people with some forms of macular degeneration when using a specific formulation of antioxidant nutrients. Further studies are under way to investigate other potentially beneficial compounds.
Macular Degeneration
Macular degeneration comes in two forms, wet and dry. Dry AMD can begin in one or both eyes and involves a gradual loss of central vision that spreads outward. Wet AMD involves a sudden, severe loss of vision and often occurs as a progression of dry AMD. Both types are caused by damage to the macula, a part of the retina of the eye. Nutritional supplementation can help people with the dry form of AMD, but not the wet form.
Research
The Age-Related Eye Disease study, or AREDS, was a clinical trial investigating the use of vitamins and minerals as a treatment for macular degeneration. The results of AREDS indicated a 25 percent reduction over five years in the progression to advanced AMD in patients with intermediate AMD or advanced AMD in only one eye, when using a supplement containing vitamins C, E, beta-carotene, and zinc with copper, according to "Current Opinions in Opthamology."
Doses
The doses used in the AREDS study are available as a specific combination supplement called the AREDS formulation, or they can be taken independently. The formulation includes a daily dose of 500 mg of vitamin C and 400 IU of vitamin E. Vitamin A, in the form of beta-carotene, is supplied at 15 mg per day. The formulation also includes 80 mg of zinc and 2 mg of copper.
Additional Supplementation
In addition to vitamins and minerals, other supplemental compounds may help in the prevention or treatment of macular degeneration. According to "Current Opinions in Opthalmology," as of May 2010, a second clinical trial titled AREDS2 is under way to investigate the impact of supplementation with omega-3 fatty acids and the phytochemicals zeaxanthin and lutein on macular degeneration. Previous observational studies, including a December 2010 study in the journal "Opthalmology," have indicated a link between omega-3 fatty acid ingestion and a lowered risk of AMD. A 2009 review in the journal "Critical Reviews of Food Science and Nutrition" found evidence of links between the consumption of lutein and zeaxanthin and a reduction in AMD.
Considerations
The results of studies performed so far, including the AREDS research, have not found any consistent link between supplementation and the prevention of AMD in individuals who do not already have some degree of the disease. In patients with intermediate AMD, however, supplementation with the AREDS formulation may be helpful and is recommended by the National Eye Institute. Because high levels of zinc can result in a copper deficiency, supplementation with zinc should always be done under the supervision of a physician, and copper supplements should be taken in conjunction with the zinc.
References
- "Current Opinions in Opthalmology": Nutritional supplements for age-related macular degeneration.
- University of Maryland Medical Center: Macular Degeneration
- Eye Care America: Antioxidant Supplements and Age-Related Macular Degeneration
- "Critical Reviews of Food Science and Nutrition": Associations between lutein, zeaxanthin, and age-related macular degeneration: an overview.
- Medline Plus: Can Omega-3 Foods Prevent Eye Disease in Seniors?
