Omega-3 fatty acids create chemical compounds known as bioactive mediators, which protect against the growth of abnormal blood vessels, a condition that characterizes some forms of retinopathy. In part, this occurs because these mediators suppress a type of inflammatory protein called tumor necrosis factor alpha (TNF-alpha). TNF-alpha is found in one type of cell, called microglia, that can be closely associated with retinal blood vessels.

?The retina has one of the highest concentrations of omega-3 fatty acids in the body,? said lead author and NEI fellowship recipient Kip M. Connor, Ph.D., a postdoctoral research fellow at Children?s Hospital Boston. ?Given this, it is remarkable that with only a two percent change in dietary omega-3 intake, we observed an approximate 40-50 percent decrease in retinopathy severity.?

?Our findings represent new evidence suggesting the possibility that omega-3 fatty acids act as protective factors in diseases that affect retinal blood vessels,? said John Paul SanGiovanni, Sc.D., NEI staff scientist and the other lead author of the study. ?This is a major conceptual advance in the effort to identify modifiable factors that may influence inflammatory processes implicated in the development of common sight-threatening retinal diseases.?

These study results, SanGiovanni emphasized, are important because they provide a reasonable biological explanation for findings from a number of human studies on diet and retinal disease, and they identify low-cost and widely available nutrient-based treatment approaches that may show merit in future research on diseases that damage retinal blood vessels and nerve cells.

"The purpose of our study was to discover and describe the scientific basis for any possible protective role of omega-3 fatty acids against retinopathy,? said Lois E. H. Smith, M.D., Ph.D., senior investigator of the study and associate professor of ophthalmology at Children?s Hospital Boston, an affiliate of Harvard Medical School. ?By identifying the fatty acids, lipids and growth factors involved in both the disease and protective processes, we hope to translate this work to influence the outcome in patients. Our study results suggest that increasing omega-3 fatty acid intake in premature infants may significantly decrease the occurrence of ROP. This changing of lipids by dietary means may also translate to AMD and diabetic retinopathy. If clinical trials find that supplementing with omega-3 fatty acids is as effective in protecting humans against retinal disease as demonstrated by the findings of this study, this cost effective intervention could benefit millions of people."

The NEI is currently conducting the Age-Related Eye Disease Study 2 (AREDS2) that will, in part, assess the effect of omega-3 fatty acids DHA and EPA on the progression of AMD. In addition, an upcoming clinical trial at Children?s Hospital Boston will test the effects of omega-3 supplements in premature infants.