By Mark S. Siegel, MD, FAAO
More than a decade after the first age-related eye disease study (AREDS) showed that taking daily high doses of vitamins C and E, beta-carotene, zinc and copper can slow down the progress of age-related macular degeneration (AMD) a second study (AREDS 2) has revealed that adding certain antioxidants to the original formula does not provide any extra benefit to patients.
Advanced AMD can lead to significant vision loss, and in the United States it is the leading cause of blindness. About 2 million Americans have advanced AMD; another 8 million are at risk.
The first AREDS study was conducted by the National Eye Institute and concluded in 2001. It showed that the original AREDS formula could reduce patients’ risk of the advanced form of AMD by about 25 percent. The formula helps protect people’s central vision, which is needed for reading, driving, recognizing faces and other daily activities.
AREDS2, which concluded in 2011, tested several antioxidant nutrients that earlier research had suggested might protect the eyes: lutein, zeaxanthin, and omega-3 fatty acids. Omega-3 fatty acids are produced by plants and are present in oily fish such as salmon. Lutein and zeaxanthin are carotenoids, a class of plant-derived vitamins that also includes beta-carotene, and are present in leafy green vegetables. The body uses these nutrients to maintain the health of the retina, the part of the eye that can be damaged by AMD. Participants in AREDS2 were assigned to take one of four different AREDS formulas daily for five years.
The AREDS2 research team did find that two patient subgroups benefited from taking variants of the original AREDS formula. The risk of developing advanced AMD was reduced by about 18 percent in study participants who took the variant that included lutein and zeaxanthin but no beta-carotene, compared with participants who took the variant that had beta-carotene but no lutein or zeaxanthin. And those participants whose diets were low in lutein and zeaxanthin at the start of the study, but who took a variant with lutein and zeaxanthin during the study, were about 25 percent less likely to develop advanced AMD, compared with similar participants who did not take lutein and zeaxanthin.
The researchers say that removing beta-carotene from the AREDS formula and adding lutein and zeaxanthin will result in a single formula that is safe and effective for all AMD patients. Until now, people who were current or former smokers could only use a formula that excluded beta-carotene, because it had been linked to risk of lung cancer for these patients. About half of AREDS2 participants were former smokers.
Another recent AREDS report showed that the benefits of taking the AREDS formula appear to be long-lasting. Participants in the first AREDS study who took the original formula daily for five years continue to enjoy a 25 percent lower risk of developing advanced AMD. Most report that they are still taking the supplement.
It is recommended that you discuss these research results with your ophthalmologist and primary care physician before changing or adding a supplement to your regimen.