By Kimberly Beauchamp, ND
Healthnotes Newswire (June 28, 2007)—Vitamin D might prevent age-related macular degeneration, the leading cause of severe vision loss in people over age 60, a new study shows.
Macular degeneration is a progressive disease of the eye that causes destruction of the macula, the part of eye responsible for central vision. Damage to the macula results in blurred vision or a blind spot in the center of the visual field. Because this is the part of the eye responsible for straight-ahead vision, tasks such as reading, driving, recognizing faces, and doing detailed work become difficult.
People with a family history of the disease, seniors, women, people with light-colored eyes, smokers, and people with cardiovascular disease are at higher risk for developing macular degeneration. Certain nutritional deficiencies have also been linked to a higher disease risk, while the antioxidant vitamins A, C, E, and zinc seem to help protect against it.
The new study examined the relationship between blood levels of vitamin D and macular degeneration risk. In the third National Health and Nutrition Examination Survey (NHANES III), 7,752 people gave information about their supplement use and typical diet. Sunlight exposure—a major source of vitamin D—was not estimated.
People with the highest blood levels of vitamin D were 36% less likely to have early macular degeneration than were people with the lowest levels; vitamin D status was not associated with the risk of more severe (advanced) macular degeneration.
People who drank milk had higher vitamin D levels and lower risk of early macular degeneration. Among people who drank less than one serving of milk per day, taking a vitamin D supplement also reduced the risk. Although eating fish did not affect vitamin D levels in the study, eating fish once or more per week was protective against advanced disease.
Some researchers believe that inflammation might be responsible for macular degeneration. “We speculate that vitamin D may reduce the risk of macular degeneration by its anti-inflammatory properties,” said the authors. Fish oil is high in anti-inflammatory omega-3 fatty acids, possibly explaining its protective effect against macular degeneration.
So how much vitamin D is needed to prevent macular degeneration? The authors commented, “At this time there is insufficient evidence of the relationship between vitamin D levels and macular degeneration to make recommendations regarding optimum blood levels of vitamin D or milk or fish intake to protect against macular degeneration. The results warrant further investigation.”
(Arch Ophthalmol 2007;125:661–9)
Kimberly Beauchamp, ND, earned her bachelor’s degree from the University of Rhode Island and her Doctorate of Naturopathic Medicine from Bastyr University in Kenmore, WA. She cofounded South County Naturopaths in Wakefield, RI. Dr. Beauchamp practices as a birth doula and lectures on topics including whole-foods nutrition, detoxification, and women’s health.
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