Omega-3 fatty acids can be found in high concentrations in the retina of the eye, leading to speculation that adequate levels of the substance may be important in preventing some diseases of the eye. Animal studies also suggest that omega-3s, found mostly in seafood, protect against eye diseases. A new study adds more evidence, finding that people who consume a lot of fish and shellfish have lower rates of age-related macular degeneration.

The condition is the most common cause of blindness in the United States. Researchers at the Wilmer Eye Institute at the Johns Hopkins School of Medicine looked at food intake over one year among 2,391 people ages 65 to 84. The participants were also evaluated for age-related macular degeneration. The study found that people with advanced disease were significantly less likely to consume fish or shellfish high in omega-3s.

Researchers also examined whether zinc, found in high quantities in crab and oysters, affected the risk, but no relationship was found.