A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8.

Study answer

What this study found

The combination of antioxidants plus zinc provided the clearest benefit in higher-risk AMD (Categories 3 and 4), reducing progression to advanced AMD and visual acuity loss. At 5 years, progression to advanced AMD was 20% with antioxidants plus zinc versus 28% with placebo, with OR 0.66 (0.47-0.91) and P=.001; ≥15-letter visual acuity loss was 23% versus 29%, with OR 0.73 (0.54-0.99) and P=.008. The combination also reduced development of neovascular AMD, OR 0.62 (0.43-0.90), P=.001. Zinc alone showed a smaller benefit and antioxidants alone were weaker and often not statistically significant.

Study & population

This was a multicenter randomized, placebo-controlled trial in 11 retinal specialty clinics in the United States.

Intervention

Participants were randomized to high-dose oral antioxidant supplementation with vitamin C 500 mg, vitamin E 400 IU, and beta carotene 15 mg twice daily, zinc 80 mg daily as zinc oxide with copper 2 mg as cupric oxide, or the combination of antioxidants plus zinc.

Key limitation

Benefits were concentrated in higher-risk AMD, so findings are less informative for lower-risk participants.

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Original abstract