Fish and Vitamin D Intake Linked to Lower Risk of Macular Degeneration
Posted Sep 20 2007 12:00am
Age-related macular degeneration, also known as AMD, is a progressive eye disease of the retina that affects the light-sensing cells in the central area of vision and dims contrast sensitivity and color perception. The condition is thought to be caused by a combination of genetic and environmental factors, and is most common in people who are age sixty and over. AMD is the leading cause of visual impairment in senior citizens.
In the first study, researchers evaluated habitual nutrient intake through food frequency questionnaires of over 4,500 people between ages 60 and 80 who participated in a study by the National Institute of Health’s National Eye Institute. Researchers found that higher dietary intakes of omega-3 long-chain polyunsaturated fatty acids, mainly from fatty fish, reduced the risk of age- related macular degeneration. The researchers speculate that these fatty acids may help promote cell health and survival as well as improve blood vessel function.
In the second study, researchers evaluated serum vitamin D and early and advanced macular degeneration in over 7,752 individuals from the National Health and Nutrition Examination Survey III (NHANES III). Researchers noted that vitamin D intake was associated with a reduced risk of developing poor visual health that can lead to blindness. Participants were split into five groups based on the level of vitamin D in their blood. Those with the highest level had a 40% reduced risk of developing poor visual health compared with those with the lowest amount of vitamin D in their blood. These results support the idea that lower serum vitamin D levels may lead to progression of chronic diseases, specifically those associated with inflammation. This may be important to the health of older Americans who have a higher risk of insufficient vitamin D intake, the researchers said.
While these results are promising, researchers caution that at this time there is insufficient epidemiologic evidence of the relationship between vitamin D and age-related macular degeneration to make recommendations regarding optimum vitamin D levels and fish intake to protect against the eye disease or its progression. These results warrant additional investigation to further confirm the role of omega-3 long-chain polyunsaturated fatty acids and vitamin D in AMD.