Researchers have more good news for those who enjoy eating fish. A meta-analysis published in the June issue of Archives of Ophthalmology found that consumption of foods high in omega-3 fatty acids, such as fish and flax, is linked to a reduction in the risk of age-related macular degeneration (AMD) – a common eye disease. However, the authors indicate a need for more clinical trials before they can advocate routine consumption of these foods for the prevention of AMD.

“Age-related macular degeneration (AMD) is the leading cause of severe vision loss among elderly people,” write the authors. There are a few newer treatments for certain forms of AMD, but they are not without risk. “Thus, primary prevention of AMD by modifying risk factors (e.g., cigarette smoking) remains an important public health strategy.”

To evaluate the potential association between omega-3 fatty acids and AMD prevention, researcher Elaine W-T. Chong, M.B.B.S. (University of Melbourne, Australia) and colleagues systematically reviewed studies that were published before May 2007. They analyzed nine studies that contained 88,974 participants, of which 3,203 had AMD.

Combining the study results, the researchers found that patients with a high dietary intake of omega-3 fatty acids had a 38% lower risk of late (more advanced) AMD. Additionally, an association was observed between eating fish two times a week and having a reduced risk of both early and late AMD.

The physiological explanation for the association is in part due to the fact that, “Long-chain omega-3 fatty acids, docosahexaenoic acid in particular, form an integral part of the neural retina.” AMD may begin as an omega-3 fatty acid deficiency results from the shedding and regeneration of these outer nerve cells of the retina. “A diet rich in omega-3 fatty acids and fish, as a proxy for long-chain omega-3 fatty acid intake, has therefore been hypothesized as a means to prevent AMD.”

The authors conclude that, “Although this meta-analysis suggests that consumption of fish and foods rich in omega-3 fatty acids may be associated with a lower risk of AMD, there is insufficient evidence from the current literature, with few prospective studies and no randomized clinical trials, to support their routine consumption for AMD prevention.”

Dietary Omega-3 Fatty Acid and Fish Intake in the Primary Prevention of Age-Related Macular Degeneration: A Systematic Review and Meta-analysis
Elaine W-T. Chong; Andreas J. Kreis; Tien Y. Wong; Julie A. Simpson; Robyn H. Guymer
Archives of Opthalmology (2008). 126[6]:826-833.
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Written by: Peter M Crosta