AREDS
The Age-Related Eye Disease Study
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 fifteen
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 or not and 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)
|
25 000 |
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 with 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.
|