Antioxidants and Carotenoid Supplements for Eye Health
Supplements of antioxidants and carotenoids may improve eye health in people with age-related macular degeneration (AMD), a new study suggests.
Macular degeneration is a degenerative disease of the retina (a thin layer of nerve cells that lines the back of the eyeball) that causes progressive loss of central vision.
Central vision loss is due to the deterioration of the central part of the retina, known as the macula. The macula is involved in detailed vision. Light sensing cells in the macula, known as photoreceptors, convert light into electrical impulses. Then the impulses are transferred to the brain via the optic nerve. Central vision loss from macular degeneration occurs when photoreceptor cells in the macula degenerate.
The risk of developing macular degeneration increases with age. The disease most often affects people in their sixties and seventies. Age-related macular degeneration is the most common type of macular degeneration and is the leading cause of legal blindness in people older than 60 years in the United States. Most individuals with macular degeneration retain peripheral vision and learn to optimize the use of their remaining vision.
The disease affects more than 10 million Americans, including 23 percent of Americans older than 90 years. Because overall life expectancy continues to increase, age-related macular degeneration has become a major public health problem.
Deficiencies in antioxidants (specifically zinc and vitamins A, C and E) have been noted in some people with age-related macular degeneration. Antioxidants may protect against age-related macular degeneration by preventing free radicals or unstable oxygen from damaging the retina. Antioxidants can be found in foods such as green, leafy vegetables, vegetables of color (oranges, yellows, purples) and fruits. Dietary and lifestyle changes are necessary, including eating less fat (from meats and dairy products) and eating more vegetables and fruits, increasing exercise and controlling weight.
Researchers from Italy evaluated the influence of short-term carotenoid and antioxidant supplementation on retinal function in nonadvanced age-related macular degeneration (AMD).
Scientists divided 27 patients with nonadvanced AMD and visual acuity greater than or equal to 0.2 logarithm of the minimum angle of resolution into two age-similar groups: 15 patients had oral supplementation of vitamin C (180 milligrams), vitamin E (30 milligrams), zinc (22.5 milligrams), copper (1 milligrams), lutein (10 milligrams), zeaxanthin (1 milligrams) and astaxanthin (4 milligrams) daily for 12 months; 12 patients had no dietary supplementation during the same period. At baseline, they were compared with 15 age-similar healthy controls.
The study found that people in the antioxidant/ carotenoid supplement group showed improvements in the function of the central retina (zero to five degrees), while no improvements were observed in the peripheral retina (five to 20 degrees).
The study authors concluded that in nonadvanced AMD eyes, a selective dysfunction in the central retina can be improved by the supplementation with carotenoids and antioxidants.
1. Parisi V, Tedeschi M, Gallinaro G, et al. Carotenoids and antioxidants in age-related maculopathy italian study: multifocal electroretinogram modifications after 1 year. Ophthalmology. 2008 Feb;115(2):324-333.
2. Natural Standard Research Collaboration: The Authority on Integrative Medicine. www.naturalstandard.com. Copyright © 2008.