Age-related macular degeneration (AMD) is the most common cause of irreversible blindness in the developed world. In the United States alone, the number of patients disabled by late-stage AMD is expected to increase more than 50 percent in the next 20 years.
While the pathophysiology of AMD is not clearly understood, oxidative stress has been suggested as a leading cause. A 2001 study found that high-dose antioxidant supplementation could slow the progression of AMD. However, little research has evaluated the role antioxidants obtained through diet might play in AMD prevention.
In a recent population-based cohort study, a research team from the Netherlands analyzed patient data from 4,170 middle-aged subjects, each of whom completed a semi-quantitative food frequency questionnaire. Subjects were tracked for an average of eight years; during that time, 560 were diagnosed with AMD.
After analyzing the data, researchers found that a high dietary intake of four antioxidants - beta-carotene, vitamins C and E and zinc - was associated with a 35 percent reduced risk of developing AMD.
A below-median consumption of all four nutrients was associated with a 20 percent increased risk of AMD. Researchers noted these associations even after adjusting for age, incidence of smoking, blood pressure levels and other factors.
| Common dietary sources of beta-carotene, vitamin C, vitamin E, and zinc* | |
| Beta-carotene | Dark yellow-orange and dark green vegetables |
| Vitamin C | Citrus fruits and juices, strawberries, tomatoes, broccoli, turnip greens and other leafy greens |
| Vitamin E | Vegetable oils, almonds and other nuts, green leafy vegetables, fortified cereals |
| Zinc | Oysters, red meat, poultry, beans, nuts, whole grains, dairy products |
| *Source: Facts About Dietary Supplements. National Institutes of Health Office of Dietary Supplements. | |
"This study suggests that the risk of AMD can be modified by diet, in particular, by dietary vitamin E and zinc," concluded the researchers. "Based on this study, foods high in these nutrients appear to be more important than nutritional supplements. Until more definitive data are available, this information may be useful to persons with signs of early AMD or to those with a strong family history of AMD."
Source
Van Leeuwen R, Boekhoorn S, Vingerling JR, et al. Dietary intake of antioxidants and risk of age-related macular degeneration. Journal of the American Medical Association, Dec. 28, 2005;294(24):3101-3107.
Dynamic Chiropractic editorial staff members research, investigate and write articles for the publication on an ongoing basis. To contact the Editorial Department or submit an article of your own for consideration, email
.