Submitted to: British Journal of Ophthalmology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/3/2009
Publication Date: 6/9/2009
Citation: Chiu, C., Klein, R., Milton, R.C., Gensler, G., Taylor, A. 2009. Does eating particular diets alter risk of age-related macular degeneration in users of the Age-Related Eye Disease Study supplements?. British Journal of Opthalmology. DOI: 10.1136/bjo.2008.143412.
Interpretive Summary: Recent information suggests that the Age-Related Eye Disease Study (AREDS) supplement, enhanced intake of omega-3 fatty acids, and diminishing dietary glycemic index (dGI) are protective against advanced age-related macular degeneration (AMD). In this study, we followed 2,924 AREDS AMD trial participants for 8 years. Our data supports the idea that diet and, if necessary, supplementation can be optimized for the prevention of AMD. Practically, for early AMD prevention, instead of taking the AREDS supplement (vitamins C, E, beta-carotene, and zinc), our data suggested that people should consume more foods rich in docosahexaenoic acid (DHA). A dietary strategy for achieving an optimal level is to consume 2-3 servings per week of cold water fatty fish, such as salmon, tuna, mackerel, sardines, shellfish, and herring. In order to benefit from higher DHA intakes against early AMD, people should adapt the recommended dietary guideline no later than the age of 60, before the early stages of AMD develop. For people who already have early AMD, in addition to taking the AREDS supplement, a diet rich in DHA/EPA and low-glycemic index (GI) foods, such as whole grains, will give the best protection against further AMD progression, which may finally lead to severe vision loss. Surprisingly, we also found that AREDS supplement users who also consumed higher beta-carotene from foods had increased risk of developing end stages of AMD. This data gives a further support to eliminate beta-carotene from the AREDS formula.
Technical Abstract: Background: Recent information suggests that the Age-Related Eye Disease Study (AREDS) supplement, enhanced intake of omega-3 fatty acids, and diminishing dietary glycemic index (dGI) are protective against advanced age-related macular degeneration (AMD). Methods: Dietary information was collected at baseline and fundus photograph grades were obtained during the 8-y trial period from 2,924 eligible AREDS AMD trial participants. Using eye as the unit of analysis and multi-failure Cox proportional-hazards regression adjusted for age, sex, smoking history, body mass index, and other potential confounders, we related the risk of AMD progression to dietary intake in the four arms of the trial to evaluate the interrelationships between dietary nutrients and AREDS supplement. Results: Independent of AREDS supplementation, higher intakes of docosahexaenoic acid (DHA, >/= 64.0 vs. < 26.0 mg/d) (hazard ratio [HR] = 0.73, 95% confidence interval [CI], 0.57, 0.94), eicosapentaenoic acid (EPA, >/= 42.3 vs. < 12.7 mg/d) (HR = 0.74, 95% CI, 0.59, 0.94), and lower dGI (dGI, < 75.2 vs. >/= 81.5) (HR = 0.76, 95% CI, 0.60, 0.96) were associated with lower risk for progression to advanced AMD. Participants consuming lower dGI and higher DHA or EPA had the lowest risk (P for synergistic interaction < 0.001). Only participants in the 'placebo' (P for antagonistic interaction = 0.006) benefited from higher DHA intake against early AMD progression (HR = 0.58, 95% CI, 0.37, 0.92; Ptrend = 0.01). AREDS supplement users consuming higher (upper 50% or >/= 2.2 mg/d) beta-carotene from foods had over 50% increased risk for advanced AMD (HR = 1.52, 95% CI, 1.10, 2.11). Conclusions: Our findings suggest consuming a diet rich in DHA for early AMD prevention. For people at risk of advanced AMD, in addition to the AREDS supplement lower dGI accompanied with higher intakes of DHA and EPA appears to provide the best protection.