Increased intake of DHA was associated with a 27 per cent reduction in the progression to advanced age-related macular degeneration (AMD), while EPA was linked to a 26 per cent reduction, according to findings published in the British Journal of Ophthalmology.
AMD is a degenerative retinal disease that causes central vision loss and leaves only peripheral vision, and the leading cause of legal blindness for people over 55 years of age in the Western world, according to AMD Alliance International.
The AREDS formula, the patent for which is held by Bausch and Lomb, comprises vitamins C and E, beta carotene, zinc and copper. AREDS2 will include the antioxidant carotenoids lutein and zeaxanthin, and the omega-3 fatty acids DHA and EPA.
The new study, by researchers from Tufts University, the University of Wisconsin, and The EMMES Corporation, appears to support the inclusion of the omega-3 fatty acids, with significant reductions in the risk of advanced AMD.
“Our findings show an association of consuming a diet rich in DHA with lower progression of early AMD,” wrote lead author Ching-Jung Chiu. “In addition to the AREDS supplement, lower [dietary glycaemic index] with higher intakes of DHA and EPA was associated with reduced progression to advanced AMD.”
Chiu and his co-workers analysed dietary information from 2,924 participants eligible for the eight-year AREDS AMD trial. The highest average intakes of DHA of over 64 mg per day were associated with a 27 per cent reduction in advanced AMD, compared with intakes less than 25 grams per day. Moreover, EPA intakes over 42.3 mg per day were associated with a 26 per cent reduction, compared to intakes of less than 12.7 mg per day.
Furthermore, dietary GI of less than 75.2 was linked to a 24 per cent lower risk, compared to a dietary GO of over 81.5, added the researchers.
When considering participants in the trial’s placebo arm, only high intakes of DHA were associated with a reduced risk of early AMD progression, added Chiu.
Source: British Journal of Ophthalmology Published online ahead of print, 9 June 2009, doi:10.1136/bjo.2008.143412“Does eating particular diets alter risk of age-related macular degeneration in users of the age-related eye disease study supplements?”Authors: C-J Chiu, R Klein, RC Milton, G Gensler, A Taylor