NEI launched the Age-Related Eye Disease Study 2 (AREDS2) in 2006 to test if adding omega-3 fatty acids or lutein + zeaxanthin would make the AREDS formula more effective. Omega-3 fatty acids are produced by plants, including algae, and are present in oily fish such as salmon. Lutein and zeaxanthin are carotenoids, a class of plant-derived vitamins that includes beta-carotene. Additionally, AREDS2 investigators tested the effect of eliminating beta-carotene, which in some studies increased lung cancer risk in smokers. They also tested lowering the zinc dose.
AREDS2 investigators enrolled 4,203 participants, ages 50-85, at one of 82 clinical sites across the country. AREDS2 included only people with intermediate AMD in both eyes or intermediate AMD in one eye and advanced AMD in the other eye. AREDS2 excluded people without AMD or with early AMD because AREDS data showed no benefit for these individuals. AREDS2 investigators excluded current smokers from receiving the formulation containing beta-carotene.
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Primary randomization: AREDS2 investigators randomly assigned participants to one of the following groups:
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Secondary randomization: Additionally, 3549 AREDS2 participants were randomized to take one of the following:
The remaining participants were not randomized and generally took the AREDS formula. |
In the AREDS2 trial, adding omega-3 fatty acids or lutein + zeaxanthin to the AREDS formula had no additional overall effect on the risk of advanced AMD. However, AREDS2 participants who took antioxidants minus beta-carotene but with lutein + zeaxanthin (AREDS2 formula) had an incremental increase in benefit, compared to those who took the AREDS formula.
AREDS2 participants who were former smokers who took a formulation with beta-carotene had a higher incidence of lung cancer. The investigators found no significant changes in the effectiveness of the formulation when they removed beta-carotene or reduced the zinc dose.
Adding omega-3 fatty acids or lutein + zeaxanthin to antioxidants plus zinc (AREDS formula), had no overall effect on the need for cataract surgery.
