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Eating fish and other foods high in omega-3 fatty acids is
associated with reduced risk of the eye disease age-related macular
degeneration (AMD), according to a meta-analysis of nine previously
published studies in the June issue of Archives of Ophthalmology, one
of the JAMA/Archives journals. However, the accumulated evidence
includes few clinical trials and is insufficient to support the routine
consumption of such foods for AMD prevention, the authors note.
"Age-related
macular degeneration (AMD) is the leading cause of severe vision loss
among elderly people," they write as background information in the
article. New treatments for AMD are potentially risky and treat only
certain forms of the disease. "Thus, primary prevention of AMD by
modifying risk factors (e.g., cigarette smoking) remains an important
public health strategy."
Elaine W-T. Chong, M.B.B.S., of the
University of Melbourne, Australia, and colleagues conducted a
systematic review of studies published before May 2007 evaluating the
fish consumption and overall omega-3 fatty acid intake for the
prevention of AMD. A total of nine studies were identified with 88,974
participants, including 3,203 individuals with AMD.
When
results from all nine studies were combined, a high dietary intake of
omega-3 fatty acids was associated with a 38 percent reduction in the
risk of late (more advanced) AMD, while eating fish twice a week was
associated with a reduced risk of both early and late AMD.
"Long-chain
omega-3 fatty acids, docosahexaenoic acid in particular, form an
integral part of the neural retina," the layer of nerve cells in the
retina, the authors write. Outer cells of the retina are continually
shed and regenerated, and deficiencies of omega-3 fatty acids may
therefore initiate AMD. "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."
"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," they conclude.
Source: Journal of American Medical Association (JAMA) and Archives Journals. Released June 09, 2008.
Article abstract: Chong, E. W. T., Kreis, A. J., Y. Wong, T. Y., Simpson, J. A., and Guymer, H. G. Dietary omega-3 Fatty Acid and Fish Intake in the Primary Prevention of
Age-Related Macular Degeneration: A Systematic Review and Meta-analysis . Arch Ophthalmol., 2008;126(6):826-833.
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