Omega-3 fatty acids may prevent age-related sight loss

Increased intakes of omega-3 fatty acids may reduce the risk of developing age-related blindness by 30 per cent, reports a new study.

The new study looked at a sub-section of 1,837 people participating in Age-Related Eye Disease Study (AREDS) (1). All the participants were considered to be at a moderate-to-high risk of advanced age-related macular degeneration (AMD). Over 12 years of study, the researchers found that intakes of omega-3 fatty acids, estimated using a food-frequency questionnaire, were related to AMD risk. Participants with the highest omega-3 intakes, equivalent to about 0.11 per cent of their total energy intakes, had a 30 percent lower risk of developing AMD than people with the lowest intakes.

Being an observational study, the researchers did not consider the mechanism. However, an earlier mouse study noted lower levels of inflammatory molecules, such as prostaglandin and leukotriene, in animals with higher omega-3 intake.

The researchers wrote that if these results are generalizable, they may guide the development of low-cost and easily implemented preventive interventions for progression to advanced age-related macular degeneration.

AMD is a degenerative retinal disease that causes central vision loss and leaves only peripheral vision. It is the leading cause of legal blindness for people over 55 years of age in the Western world, according to AMD Alliance International. Despite the fact that approximately 25 to 30 million people worldwide are affected by AMD, awareness of the condition is low.

It is known that omega-3 fatty acids, and particularly docosahexaenoic acid (DHA), play an important role in the layer of nerve cells in the retina, and studies have already reported that omega-3 may protect against the onset of AMD. A meta-analysis published in 2008 found that a high intake of omega-3 fatty acids and fish may reduce the risk of AMD by up to 38 percent (2).

1. SanGiovanni JP et al. Omega-3 Long-chain polyunsaturated fatty acid intake and 12-y incidence of neovascular age-related macular degeneration and central geographic atrophy: a prospective cohort study from the Age-Related Eye Disease Study. American Journal of Clinical Nutrition. 2009.
2. Chong E. et al. Dietary Omega-3 Fatty Acid and Fish Intake in the Primary Prevention of Age-Related Macular Degeneration: A Systematic Review and Meta-analysis. Archives of Opthalmology. 2008; 126(6):826–833