Eating fish and Omega-3 fish oils may protect against age-related macular degeneration (AMD), which is a currently untreatable disease that causes fuzziness, shadows or other distortions in the center of vision and eventually leads to blindness.
Over 12 years from 1984 to 1996, investigators questioned 72,000 study participants about their diets and calculated the types of fat and total fat they ate. Those who ate more fat overall increased their risk of AMD, while those who ate fish reduced their risk of developing the eye disease.
Diets containing saturated fats from animals and unsaturated fats from vegetables were associated with modest (54%) increases in the risk of developing AMD, although long-chain fats from fish, actually reduced the risk by 30%.
A specific fish fat, called docosahexaenoic acid (DHA), may help protect and promote healthy retinal function. DHA is also concentrated in the retina of the eye. DHA was modestly (-30%) inversely related to AMD. The intake of fish, the food source of DHA, was also inversely related to AMD. Those subjects consuming >4 fish meals per week had a 35% less risk of AMD than those subjects consuming <3 fish meals per month.
Note: Because of the high concentrations of mercury and PCBs in fatty fish such as tuna and salmon, eating 4 meals of fish per week may no longer be recommended. A mix of purified fish oil and some fish meals may provide a better balance.
A new study provides a possible explanation: C-reactive Protein Levels Linked with Macular Degeneration.
Cho, Eunyoung, et al. Prospective study of dietary fat and the risk of age-related macular degeneration. American Journal of Clinical Nutrition 2001;73:209-218. http://www.ajcn.org/cgi/content/full/73/2/209