LONDON, ENGLAND. Age-related macular degeneration (AMD) is the major cause of adult blindness in developed countries. A large study involving researchers and patients from eight European countries now report that regular consumption of oily fish may reduce the risk of developing AMD by 53%. The study involved 105 patients with neovascular AMD and 2170 controls without any features of early or late AMD. All participants were 65 years of age or older. They were interviewed by field workers, underwent an eye examination, including fundus photography, and gave a blood sample. During the interview, dietary intake during the previous 12 months was assessed using a semi-quantitative food-frequency questionnaire.
Analysis of the collected data revealed that study participants who ate only oily fish (mackerel, tuna, salmon, sardines and herring) once a week (one serving equaling 4 oz or 113 g) had half the risk of AMD when compared to those who ate oily fish less frequently. No beneficial effect was observed from consuming non-oily (white) fish such as cod. Not surprisingly, the researchers observed a strong correlation between oily fish intake and the dietary intake of the two main components of fish oil – EPA and DHA (eicosapentaenoic acid and docosahexaenoic acid, respectfully). Study participants whose energy-adjusted EPA and DHA intake was greater than 302 mg/day had one-third the risk of AMD than did those whose daily intake was 105 mg or less.
The researchers found no independent association between vitamin D intake and AMD risk and adjusting for lifestyle factors such as smoking, alcohol consumption, and education did not affect the observed correlations. They point out that current recommendations for the combined intake of EPA and DHA range between 400 and 1000 mg/day, an amount that could be obtained by eating 2 servings of salmon or 26 servings of cod a week.
Augood, C, et al. Oily fish consumption, dietary docosahexaenoic acid and eicosapentaenoic acid intakes, and associations with neovascular age-related macular degeneration. American Journal of Clinical Nutrition, Vol. 88, 2008, pp. 398-406