The Age-Related Eye Disease Study
Everyone over the age of 55 should have an eye exam to determine their risk of developing advanced AMD. In 1992 the U.S. National Eye Institute initiated the Age-Related Eye Disease Study (AREDS) to see if high doses of antioxidants and zinc would have any effect on people with AMD. The goal was to determine if these supplements could help stop or slow down the progression of AMD and vision loss.
There were 3 640 people between the ages of 55 and 80 who participated in the study. By the time it ended in 2001 the participants had been under observation for an average of 6.3 years. To get a better idea of who might benefit the most from the supplements the participants were divided into four categories depending on the type and severity of their AMD at the beginning of the study:
Category 1: No AMD Category 2: Mild AMD Category 3: Intermediate AMD Category 4: Advanced AMD
The people in each of these categories were then divided into 4 groups and given supplement tablets containing different ingredients:
Group 1: zinc only Group 2: zinc plus the antioxidant vitamins C E and beta-carotene Group 3: antioxidant vitamins C E and beta-carotene only Group 4: placebo only (sugar pill)
The study required participants to receive up to five to 15 times the recommended daily allowance of these nutrients. Vitamin/mineral supplements were used because it would be impossible to get the required amount from diet alone.
The Study Results After all that time and all those vitamins how did the different categories and groups do? To be measured and then judged a success AMD would have to get worse in some people and not in others. For the people in categories one and two (with no AMD or mild AMD) there were almost no cases of AMD getting significantly worse in either of those categories. This made it difficult to tell if the supplements worked so these two categories were excluded from the final results. Quite frankly that’s good news for anyone in categories one or two.
The study did show positive results for people in categories three and four however (intermediate or advanced AMD) and the best results occurred for people in Group 2 who were taking antioxidants plus zinc. Over 5 years the likelihood that their AMD would progress to advanced AMD was only 20%. What’s more only the people in Group 2 had less vision loss. As a comparison the patients in Group 4 had a 28% chance of developing advanced AMD.
Treatment Group Likelihood of Progression of AMD Group 1: zinc only 22% Group 2: zinc plus the antioxidant vitamins C E and beta-carotene 20% Group 3: antioxidant vitamins C E and beta-carotene only 23% Group 4: placebo only 28%
While these numbers may not look big they are in fact significant and point to the positive benefits of taking the combination of zinc and the antioxidant vitamins C E and beta-carotene.
Naturally to obtain the same benefits as were seen in the study you would have to take a supplement whose formulation matched the one used in the study. There are several brands of ocular vitamins available – some formulated more closely to the AREDS formula than others.
Total daily dosage* of antioxidant vitamins and zinc consumed in the Age-Related Eye Disease Study.
Vitamin/Mineral AREDS Supplement Beta-carotene (IU/day) 25000 Vitamin C (mg/day) 500 Vitamin E (IU/day) 400 Zinc (mg/day) 80 * The AREDS supplement was taken as 2 tablets twice/day.
As with any medication anyone considering taking nutritional supplements for their AMD should first consult their eye care professional. According to the AREDS study the benefits are only proven in high-risk cases of intermediate or advanced AMD – and only your eye care professional can determine your risk level. It’s also important to know that high doses of beta-carotene can be harmful to people who smoke or have recently quit smoking. Our advice to anyone who smokes is to quit and be sure to talk to your eye care professional about your smoking history before taking a supplement. Smokers are 6 times more likely to develop AMD – so that’s another good reason to quit smoking right away!
Finally as the authors of AREDS recommend everyone over the age of 55 should have an eye exam to determine their risk of developing advanced AMD. And people who are at risk should consider taking a nutritional supplement similar to the AREDS formula.