Vitamins cannot cure age-related macular degeneration (AMD) but might prevent the development of AMD and slow its progression. AMD gradually destroys the ability to see fine details and is the leading cause of vision loss in older Americans. The Age-Related Eye Disease Study (AREDS), a federally sponsored research study of about 3,600 people, found that taking certain vitamins reduced the risk of AMD by 25 percent.
Vitamin E
This is an essential fat-soluble vitamin and a powerful antioxidant. Antioxidants are protective substances that prevent chronic conditions by destroying harmful and toxic molecules called free radicals. The Foundation of the American Academy of Ophthalmology (FAAO) says the AREDS administered 400 international units (IU) of vitamin E. According to the Office of Dietary Supplements (ODS), the recommended dietary allowance (RDA) of vitamin E for adults is 22.4 IU. Dietary sources of vitamin E include wheat germ, corn, nuts, seeds, olives, green leafy vegetables and vegetable oils.
The National Eye Institute (NEI) notes that the amount of vitamin E and other vitamins administered in the study are higher than what normal daily multivitamins provide. The amount of vitamins used in the AREDS also might be difficult to achieve through diet alone, but the eye institute says people who eat a lot of green leafy vegetables appear to have a lower risk of AMD. Medline Plus says 400 IU or more of vitamin E might be toxic because it gets stored in the body for long periods of time; however, the FAAO notes that there were no significant adverse effects associated with supplements used in the AREDS.
Vitamin C
This is an essential water-soluble vitamin and antioxidant. According to the FAAO, the AREDS vitamin formula contained 500 mg of vitamin C. The RDA for vitamin C is 75 mg per day for women and 90 mg per day for men. Foods that are naturally high in vitamin C include green peppers, citrus fruits and juices, berries, tomatoes, broccoli, leafy green vegetables, potatoes, melons, tropical fruits and winter squash. Unlike vitamin E, the risk of vitamin C toxicity is low because excess amounts of vitamin C are excreted in the urine and not stored in your body.
Beta-Carotene
This is a carotenoid, a natural food coloring, that can be converted into vitamin A. Vitamin A is an essential fat-soluble vitamin and antioxidant. According to the FAAO, approximately 14 mg of beta-carotene was administered in the AREDS, which is equivalent to 25,000 IU of vitamin A. The RDA for vitamin A is 3,000 IU for men and 2,310 IU for women. According to the ODS, although the recommended maximum intake for vitamin A is 10,000 IU, carotenoids such as beta-carotene are generally considered safe because their conversion to vitamin A decreases when vitamin A stores are full. The NEI says a side effect of beta-carotene that was reported in the AREDS was yellowing of the skin. The ODS says yellowing of the skin from beta-carotene is not considered a dangerous health risk.
References
- Foundation of the American Academy of Ophthalmology: Antioxidant Supplements and Age-Related Macular Degeneration
- National Eye Institute: The AREDS Formulation and Age-Related Macular Degeneration
- Office of Dietary Supplements: Vitamin C
- Office of Dietary Supplements: Vitamin E
- Office of Dietary Supplements: Vitamin A and Carotenoids
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