The Age-Related Eye Disease Study (AREDS) was a clinical trial sponsored by the National Eye Institute that ran from 1992 to 2001. The study was designed to:
- investigate the natural history and risk factors of age-related macular degeneration (AMD) and cataracts, and
- evaluate the effects of high doses of antioxidants and zinc on the progression of the two conditions in those with AMD.
The results were reported in the October 2001 issue of Archives of Ophthalmology. Other manufacturers also provide supplements pre-packaged with formulations based on this study.
Studies in 2016 and 2018 later showed that this average 25 percent reduction in risk from the combination of anti-oxidants and zinc varies by genotype.
AREDS2
{| class="wikitable floatright"
|+ Changes in the formulation
|-
! Ingredient !! AREDS !! AREDS2
|-
| Vitamin C || 500mg || 500mg
|-
| Vitamin E || 400IU || 400IU
|-
| Beta-carotene || 15mg ||
|-
| Cupric oxide || 2mg || 2mg
|-
| Lutein || || 10mg
|-
| Zeaxanthin || || 2mg
|-
| Zinc || 80mg || 80mg
|}
The original AREDS study was followed by AREDS2, a five-year study that started in 2006 to test whether the original AREDS formulation would be improved by adding omega-3 fatty acids; adding lutein and zeaxanthin; removing beta-carotene; or reducing zinc. In AREDS2, participants took one of four AREDS formulations: the original AREDS formulation, AREDS formulation with no beta-carotene, AREDS with low zinc, AREDS with no beta-carotene and low zinc. In addition, they took one of four additional supplement or combinations including lutein and zeaxanthin (10 mg and 2 mg), omega-3 fatty acids (1,000 mg), lutein/zeaxanthin and omega-3 fatty acids, or placebo. According to Dr. Emily Chew, "Because carotenoids can compete with each other for absorption in the body, beta-carotene may have masked the effect of the lutein and zeaxanthin in the overall analysis.". The formulation was introduced alongside a narrative review of more than 20 human studies suggesting a potential role for certain B vitamins in reducing the risk and progression of age-related macular degeneration.
Packaging
The AREDS2 formulation is often sold with all the ingredients packaged together in one pill, for convenience. These formulations may be labelled as "AREDS2", the pharmaceutical generic name, or they may be labelled with trademarked brand names, or they may be labelled with both. Some preparations not explicitly labelled as AREDS2 may not contain the correct ingredients in the correct quantities, and may contain additional, non-AREDS2 ingredients, which have no proven benefit.
The AREDS2 formulation can also be taken as a set of pills which contain the individual components in the correct quantities.