AREDS, AREDS2: (2001, 2006, 2013) Antioxidants & Choroidal Neovascularization
See more about preventing choroidal neovascularization.
The original AREDS trial discovered that patients who have macular degeneration can somewhat lower the risk of the condition degenerating to the more severe wet macular degeneration, known as choroidal neovascularation (CNV) with supplementation of zinc and antioxidants.
The benefits of the nutrients were seen only in people who began the study at high risk for developing choroidal neovascularization, (advanced macular degeneration), and in that group those taking antioxidants and zinc had the lowest risk of developing advanced stages of AMD.
In advanced AMD in addition to drusen, patients have in one or both eyes, either:
- A breakdown of light-sensitive cells and tissue in the central retinal area (advanced dry form); or
- Abnormal, fragile blood vessels under the retina that leak fluid or bleed (advanced wet form)
The researchers found that antioxidant/zinc supplementation in patients with advanced dry macular degeneration or vision loss because of wet macular degeneration in a single eye had a 20% of having their condition worsen within five years compared to 28% of patients taking a placebo.
The formulation used in the AREDs study contained several antioxidant vitamins, which are nutrients that can help maintain healthy cells and tissues. They also contained zinc, which is an important mineral incorporated into many body tissues:
- 500 milligrams of vitamin C;
- 400 international units of vitamin E;
- 15 milligrams of beta-carotene;
- 80 milligrams of zinc as zinc oxide;
- 2 milligrams of copper as cupric oxide
It has been known from earlier studies that people with diets rich in green, leafy vegetables have a lower AMD risk, but it is hard to gain the therapeutic levels needed through diet alone. Therefore the supplements were needed.
The study also showed that people who take a daily multivitamin can lower the risk of vision loss by adding the same high levels of antioxidants and zinc as in the study.
Researchers: National Institutes of Health, National Eye Institute,
Published: Archives of Ophthalmology, October, 2001
The same researchers at NIH who performed the AREDS study in 2001 wanted to determine whether adding omega-3 fatty acids, lutein and zeaxanthin to the AREDS formulation (vitamins C & E, zinc & beta-carotene) would be of value for aging patients with eye disease. Because beta-carotene is counter-indicated for smokers, they were also investigating alternatives to that nutrient.
In AREDS2, a 5 year study involving more than 4000 patients, the revised recommended formulation, based on the new research concluded that the optimal combination was as follows:
- 500mg of vitamin C
- 400 IU vitamin E
- 2mg copper
- 25mg zinc (lower level)
- 1000mg of omega-3 fatty acids
- beta-carotene deleted
The researchers concluded that the omega-3s did not improve the formulation, but because they are known to be helpful they are retained in the recommendations.
Researchers: National Institutes of Health, National Eye Institute
AREDS update, 2013
This report further established the long-term value of these nutrients. Patients taking the formulation during the 5-year AREDS2 trial were 25-30% less likely to develop advanced macular degeneration. It further concluded that long term use of the AREDS2 formulation was safe and protective against advanced AMD.
Researchers: NEI Intramural Research Program with support from National Institute of Neurological Disorders and Stroke; the National Institute on Aging; the National Heart, Lung, and Blood Institute; the National Center for Complementary and Alternative Medicine; and the NIH Office of Dietary Supplements.
Published: JAMA Ophthalmology, May, 2013.