The Effect of Antioxidant
Vitamins and Zinc on Age-Related Macular Degeneration and CataractHigh
levels of antioxidants and zinc significantly reduce the risk of advanced age-related
macular degeneration (AMD) by about 25 percent. These same nutrients also reduce
the risk of vision loss caused by advanced AMD by about 19 percent. They have
no significant effect on the development or progression of cataract. These
results are from the Age-Related Eye Disease Study (AREDS), a major clinical trial
sponsored by the National Eye Institute, one of the Federal government's National
Institutes of Health. The nutrients are not a cure for AMD, nor will they restore
vision already lost from the disease. However, they may play a key role in helping
people at high risk for developing advanced AMD keep their vision. Who
Should Take the Nutrients? People who are
at high risk for developing advanced AMD should consider taking the formulation
used in the study. Your eye care professional can tell you if you have AMD and
if you are at risk for developing the advanced form of the disease. The doctor
should give you a dilated eye exam in which drops are placed in your eyes. This
allows for a careful examination of the inside of the eye to look for signs of
AMD. If you are already taking daily multivitamins and your doctor suggests you
take the formulation used in the AREDS, review all the supplements with your doctor.
What is the Dosage of the Nutrients Used
in the Study? The specific daily amounts
of antioxidants and minerals used by the study researchers were 500 milligrams
of vitamin C; 400 international units of vitamin E; 15 milligrams of beta-carotene;
80 milligrams of zinc as zinc oxide; and two milligrams of copper as cupric oxide.
Copper was added to the AREDS formulations containing zinc to prevent copper deficiency,
which may be associated with high levels of zinc supplementation. Where
Can I Obtain the Formulation Used in the Study? Bausch
and Lomb, an eye care company, was a collaborator in the AREDS and provided the
study nutrients. The company markets the formulation used in the AREDS; other
companies may provide similar formulations. Antioxidant vitamins and zinc can
also be purchased separately; however, consumers should discuss the use of these
high levels of nutrients with their doctors, and be certain to include copper
whenever taking high levels of zinc. Are
There Any Side Effects from the Nutrients? The
AREDS participants reported few side effects from the treatments. About 7.5 percent
of participants assigned to the zinc treatments--compared with five percent who
did not have zinc in their assigned treatment--had urinary tract problems that
required hospitalization. Participants in the two groups that took zinc also reported
anaemia at a slightly higher rate; however, testing of all patients for this disorder
showed no difference among treatment groups. Yellowing of the skin, a well-known
side effect of large doses of beta-carotene, was reported slightly more often
by participants taking antioxidants. In two large clinical trials sponsored by
the National Cancer Institute, beta-carotene was shown to significantly increase
the risk of lung cancer among smokers. | 
