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RESEARCHERS TAKE SECOND LOOK AT AMD SUPPLEMENTSIf you're taking nutritional supplements for age-related macular degeneration (AMD), the range of choices can be bewildering. Browse the aisles of your local pharmacy, and you'll find an array of products designed to prevent or slow this common eye condition. Many contain the original combination used in the landmark Age-Related Eye Disease Study – or AREDS - while others have modified the formulation by adding other antioxidants to the mix or adjusting the dosage.
But recent results of a follow-up nutrition study from the National Eye Institute (NEI) should clarify those choices. Known as AREDS2, the large-scale clinical trial found that adding omega-3 fatty acids did not improve the routinely prescribed "AREDS" vitamins for AMD. The findings also resulted in the recommendation that lutein and zeaxanthin be added to the AREDS formulation in place of beta carotene. The study was published online May 5, 2013 in the Journal of the American Medical Association.
"The study not only reaffirms the value of AREDS vitamins in helping preserve vision, it simplifies the decision about which type of supplement to take," says Michael Klein, M.D., principal investigator of the clinical site in Portland. "All at-risk patients - both smokers and non-smokers - can benefit from the same formula that replaces beta carotene with lutein and zeaxanthin," he says.
Co-investigators of the Portland study, a cooperative effort between Casey Eye Institute and Devers Eye Institute, included Steven Bailey, M.D., Thomas Hwang, M.D., Andreas Lauer, M.D., and Tim Stout, M.D., Ph.D., M.B.A.
The first AREDS trial, which concluded in 2001, found that daily high doses of vitamins C, E, beta carotene and the minerals zinc and copper slow progression of advanced AMD among patients most at risk. Those helpful effects are long-lasting, according to another recently published study, which followed the first AREDS participants for an additional five years.
AREDS2 was launched in 2006 to learn if the original combination could be improved by adding the antioxidants lutein, zeaxanthin and omega-3 fatty acids, removing beta carotene or lowering the dose of zinc.
Early research showed that omega-3 fatty acids, along with lutein and zeaxanthin may help protect against AMD. Lutein and zeaxanthin are plant pigments found in many fruits and vegetables. Although our bodies are unable to produce lutein and zeaxanthin, they are obtained from our diet and highly concentrated in the macula of healthy retinas. Omega-3 fatty acids are found in cold-water fish, such as salmon and tuna, and included in fish oil capsules.
Researchers wanted to re-evaluate the original formulation without beta carotene because it may cause lung problems in some smokers. They also reduced the amount of zinc in the trial since high dosages have been to known to cause minor side effects in a small number of patients.
The nearly 4,000 participants enrolled in the study were randomly given one of four AREDS formulations as well as lutein/zeaxanthin; omega-3 fatty acids; lutein/zeaxanthin and omega-3 fatty acids; or placebo.
Among the key findings from the AREDS2 trials were:
- Adding omega-3 fatty acids or lutein/zeaxanthin to the original formulation (containing beta carotene) had no overall effect on AMD. However, people who took AREDS containing lutein/zeaxanthin and no beta carotene had a slight reduction in risk of advanced AMD, compared with those who took AREDS with beta carotene.
- Adding lutein/zeaxanthin to the AREDS formulation may help people with very low levels of lutein/zeaxanthin in their diet.
- Former smokers who took AREDS with beta carotene had a higher incidence of lung cancer.
- Removing beta carotene from the formulation or lowering the amount of zinc did not lessen its effectiveness.
The AREDS supplements are available without a prescription and are recommended for people with intermediate AMD (large drusen deposits) in either eye or an advanced stage in one eye. Your eye doctor can tell you if you are a candidate for the multivitamins and recommend the combination that is best for you.
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