Omega-3 Fatty Acids Appear to Cut Risk of Age-Related Blindness
Lee Swanson Research Update
The US National Eye Institute reports that increased intakes of omega-3 fatty acids may reduce the risk of developing age-related blindness by 30%.
A subsection of the Age-Related Eye Disease Study (AREDS) supported the beneficial effects of omega-3 consumption for preventing age-related macular degeneration (AMD), the leading cause of blindness in people over 50.
"If these results are generalizable, they may guide the development of low-cost and easily implemented preventive interventions for progression to advanced age-related macular degeneration," wrote the researchers, led by John Paul SanGiovanni.
AMD is a degenerative retinal disease that causes central vision loss and leaves only peripheral vision. It is the leading cause of legal blindness for people over 55 years of age in the Western world, according to AMD Alliance International.
Despite the fact that approximately 25 to 30 million people worldwide are affected by AMD, awareness of the condition is low, says the Alliance. And as the generation of Baby Boomers gets older, the Alliance expects incidence to be on the rise and triple by 2025.
There are two types of AMD—wet and dry. The former occurs when blood vessels grow abnormally beneath the macula (neovascular AMD). The blood vessels eventually leak and the macula is scarred, obscuring vision. Dry AMD occurs when normal tissue in the macula slowly disappears. This results in a pale area of the macula called central geographic atrophy.
Increased intakes of omega-3 fatty acids may reduce the risk of both wet and dry AMD by 35% and 32%, respectively, according to findings published in the American Journal of Clinical Nutrition.
It is known that omega-3 fatty acids, and particularly DHA, play an important role in the layer of nerve cells in the retina, and studies have already reported that omega-3 may protect against the onset of AMD.
Indeed, a meta-analysis published in the June 2008 issue of the Archives of Ophthalmology found that a high intake of omega-3 fatty acids and fish may reduce the risk of AMD by up to 38%. Scientists from the University of Melbourne in Australia reported that the benefits were most pronounced against late (more advanced) AMD, while eating fish twice a week was associated with a reduced risk of both early and late AMD.
The new study supports these earlier findings. SanGiovanni and his co-workers looked at a sub-section of 1,837 people participating in the phase 3 (AREDS). All the participants were considered to be at a moderate-to-high risk of advanced AMD.
Over 12 years of study, the researchers found that intakes of omega-3, estimated using a food-frequency questionnaire, were related to both wet and dry AMD risk.
Participants with the highest omega-3 intakes, equivalent to about 0.11% of their total energy intakes, had a 30% lower risk of developing both types than people with the lowest intakes.
"The 12-year incidence of central geographic atrophy and neovascular AMD in participants at moderate-to-high risk of these outcomes was lowest for those reporting the highest consumption of omega-3 fatty acids," the researchers concluded.
American Journal of Clinical Nutrition Published online ahead of print.