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EW RETINA January 2011 21 Looking for an AMD dietary connection with foods rich in omega-3-fatty acids R ecent study results sug- gest that patients with ad- vanced AMD are less likely to consume fish or shellfish, according to Susan B. Bressler, M.D., professor of ophthalmology, Wilmer Eye Insti- tute, Johns Hopkins University, Bal- timore. In a recent study published in the July 2010 issue of Ophthalmol- ogy, investigators considered how participants in the Salisbury Eye Evaluation (SEE) were affected by fish and shellfish consumption when it came to age-related macular degeneration. Investigators were spurred to look for a possible link between AMD and fish and shellfish con- sumption by previous work. "Other population-based studies have shown an inverse association be- tween dietary omega-3 fatty acid in- take and the risk of late AMD," Dr. Bressler said. "We sought to confirm this relationship, and unlike previ- ous research, we included both fish and shellfish intake in the determi- nation of omega-3 fatty acid con- sumption." This was natural here because shellfish, particularly crab and oysters, was a main component of the SEE diet. Considering food frequency This cross-sectional study involved dietary and ophthalmic data from 2,520 Maryland residents, according to Bonnielin Swenor, M.P.H., re- search data analyst, Wilmer Eye In- stitute. Those included were 65-84 years of age. The participants were asked about their diets. "For this cross-sectional study, a food fre- quency questionnaire was used to quantify the diet of SEE participants over the previous year," Ms. Swenor said. "AMD status was assessed by two independent graders from fun- dus photographs." The photographs taken at baseline were graded for drusen size. Those participants with drusen measurements of 125 mi- crons or more were categorized as having large deposits. Investigators also considered whether participants had retinal pigment epithelial ab- normalities, had advanced AMD, were free of abnormalities, and were among the group of controls. "The relationship between AMD status and the intake of fish and shellfish was examined," Ms. Swenor said. When investigators considered results they found that they were quite striking. "Our results indicated that participants of the SEE study who consumed one or more serving per week of fish and shellfish high in omega-3 fatty acids had a reduced risk of advanced AMD as compared to those who consumed fish or shellfish less frequently," Ms. Swenor said. However, when con- sumption of crabs and oysters, which have high levels of zinc, were combined, there was no relationship to AMD found. An omega-3 link Fish's protective role appears poten- tially linked to omega-3 content, ac- cording to Dr. Bressler. "While we did not investigate the impact of in- dividual types of fish or seafood, we found that elevated intake of fish and seafood high in omega-3 fatty acids, such as crab and oysters, had a protective effect on the risk of ad- vanced AMD," she said. Investigators theorized that omega-3 in such fish and shellfish is somehow protecting the retina in advanced AMD cases. "Omega-3 fatty acids are highly concentrated in the retina and are thought to pro- tect this tissue from insult," Ms. Swenor said. "There are many hy- pothesized mechanisms for the im- pact that omega-3 fatty acids have on the risk of AMD, and more re- search is needed to elucidate the full details of these pathways." Dr. Bressler sees the study as providing greater evidence of the value of consuming omega-3-rich foods to protect against AMD. "Our study provides further evidence of an inverse association between di- etary omega-3 fatty acid intake and advanced AMD risk," Dr. Bressler said. However, she cautions against drawing clinical conclusions just yet. "While our findings contribute to a body of literature indicating that a diet rich in omega-3 fatty acids may reduce the risk of advanced AMD in some patients, more research is nec- essary," Dr. Bressler said. "AMD pa- tients should fully discuss dietary options with their ophthalmolo- gist." Ms. Swenor concurs. "More re- search is required to translate popu- lation-based findings to a clinical setting," she said. A clinical trial would allow for both prospective data collection and controlled ad- ministration of omega-3 fatty acids. Going forward, the hope is that the Age-Related Eye Disease Study 2 (AREDS2) will provide needed an- swers here. "Currently, AREDS2, a randomized clinical trial conduced by the National Eye Institute [Bethesda, Md.], is investigating the effect that omega-3 fatty acid sup- plements may have on the progres- sion to advanced AMD," Ms. Swenor said. "We expect the results from this trial to provide further in- sight into the association between omega-3 fatty acids and advanced AMD." EW Editors' note: Dr. Bressler and Mr. Swenor have no financial interests re- lated to their comments. Contact information Bressler: sbressler@jhmi.edu Swenor: ssceurm1@jhmi.edu by Maxine Lipner Senior EyeWorld Senior Contributing Editor No fish ... does food stave off AMD? Consuming fish may help to keep advanced AMD at bay and spare patients from viewing an Amsler grid pattern like this Source: National Eye Institute