In 2001, Age-Related Eye Disease Study (AREDS) researchers reported that a nutritional supplement called the AREDS formulation could reduce the risk of developing advanced age-related macular degeneration (AMD).
In 2006, the same research group, which is based at National Institute of Health’s National Eye Institute, began a second study called AREDS2 to determine if they could improve the AREDS formulation. They tested the following: adding the antioxidants lutein and zeaxanthin, adding omega-3 fatty acids, removing beta-carotene, and lowering the dose of zinc.
What is the original AREDS formulation?
500 milligrams (mg) of vitamin C
400 international units of vitamin E
15 mg beta-carotene
80 mg zinc as zinc oxide
2 mg copper as cupric oxide
What modifications were tested in AREDS2?
10 mg lutein and 2 mg zeaxanthin
1000 mg of omega-3 fatty acids (350 mg DHA and 650 mg EPA)
25 mg zinc
Why did they change the AREDS2 formulation?
Why add lutein/zeaxanthin and omega-3 fatty acids? Previous studies had found that dietary intake of lutein/zeaxanthin and omega-3 fatty acids is associated with a lower risk of developing advanced AMD.
Why eliminate beta-carotene? During the AREDS trial, two large trials funded by the National Cancer Institute found that beta-carotene may increase lung cancer risk among people who smoke. Lutein and zeaxanthin are in the same family of nutrients as beta-carotene and are believed to have important functions in the retina. Therefore, the researchers theorized that lutein/zeaxanthin might be a safer and possibly more effective alternative than beta-carotene.
Why reduce zinc? Although zinc was found to be an essential component of the AREDS formulation in the original trial, some nutritional experts recommended a lower dose.