|
|
|
Set Text Size:  |  |
|
Background |
 Physicians have long
debated whether taking vitamin and/or mineral
supplements could help prevent or slow down
age-related macular degeneration (AMD). Some early
scientific studies seem to show that supplements
including zinc could slow the progression of AMD,
although more complete studies were needed to
answer some important questions:
- Which
supplements are most helpful?
- Which patients
benefit from supplementation?
- What doses of
supplements would benefit patients?
- What side
effects might these supplements have?
A recent study, the
Age-Related Eye Disease Study (AREDS), sought to
address these questions, and seems to have given
us some (but not all) of the answers to these
questions: |
What
is AREDS? |
The
Age-Related Eye Disease Study (AREDS) is a major
study sponsored by the National Eye Institute (NEI),
one of the Federal Government’s National
Institutes of Health, and conducted at eleven
major medical research facilities around the
country. In the study, scientists looked at the
effects of zinc and antioxidants, and a
combination of both, on patients with cataract,
and on those with varying stages of age-related
macular degeneration (AMD). They also studied patients without evidence
of cataract or AMD to determine if the supplements
can prevent the development of these
conditions. |
What
were the results? |
The study showed a
number of important things:
- High levels of
antioxidants and zinc can reduce the risk of
vision loss from advanced AMD by about 19% in
high-risk patients (patients with intermediate
AMD or advanced AMD in one eye but not the
other).
- Supplements do
not provide significant benefit in patients
with minimal AMD.
- These
nutritional supplements do not prevent the
initial development of AMD, nor do they
improve vision already lost to AMD.
- Nutritional
supplements do not seem to prevent cataracts,
or to keep them from getting worse over
time. While most patients in the study
experience no serious side effects from the
doses of zinc and antioxidants used, a few
taking zinc alone had urinary tract problems
that required hospitalization. Some patients
taking large doses of antioxidants experienced
some yellowing of the skin. The long-term
effects of taking large doses of these
supplements are still unknown.
|
Should
I take nutritional supplements? |
If you have
intermediate AMD (or advanced AMD in one eye only)
talk to your physician about taking nutritional
supplements. He or she can help you determine if
they may be beneficial--and safe--for you, and
what types and doses of supplements to take. The
doses used in the study were:
- Vitamin C 500mg
- Vitamin E 400 IU
- Beta-carotene 15
mg
- Zinc 80 mg as
zinc oxide
- Copper 2 mg as
cupric oxide (copper should be taken with
zinc, because high-dose zinc is associated
with copper deficiency).
The vitamin
preparation used in the study is now commercially
available. Two of these supplements on the market
are Ocuvite-PreserVision (2 tablets twice a day)
and Alcon ICaps (AREDS formula) (2 tablets twice a
day). Other similar preparations may also be
available.
Smokers and
ex-smokers probably should not take beta-carotene,
as studies have shown a link between beta-carotene
use and lung cancer among smokers.
Finally, the AREDS
did not investigate whether the supplement, lutein,
was of any benefit. This yellow pigment is present
in the macula and is not produced in the body. Its
primary source is dark green and leafy vegetables.
Many investigators think that lutein may also be
of benefit in preventing or slowing the
progression of AMD. Eating extra amounts of dark
green and leafy vegetables or using a supplement
containing lutein may be beneficial. Patients
taking the anticoagulant, Coumadin, should not
increase the amount of green and leafy vegetables
without consulting their physician.
Dark
Green Leafy Vegetables – Disease Fighters |
It may be very
likely that Popeye will never be treated for
macular degeneration. Why is this? This is
because his favorite food is spinach, one of
the richest forms of the antioxidant lutein.
Researchers from Harvard University found
that people who eat the most lutein-rich
foods are 43% less likely to develop
age-related macular degeneration. People
most protected from age-related macular
degeneration eat 5 or more helpings of
spinach or collard greens per week. Lutein,
a form of beta-carotene, is most highly
concentrated in dark green leafy vegetables:
mustard greens, collard greens, spinach and
kale.  Another benefit of a diet rich in
vegetables is a decreased risk of cancer and
cardiovascular disease. These greens are
available at your local grocery store and
each helping must be at least ½ cup cooked
or raw.
Just as there
are many types of greens, there are also
many ways to prepare them. Greens can be raw
in salads, cooked with lemon juice, and
seasoned with dill. Shopping for greens is
easy. Look for tender, young, unblemished
leaves of bright green color. These
vegetables should be at the grocery store
year round.
Cooking
greens is just as easy as shopping for them.
Remove the ends and imperfect leaves. Wash
several times in water, lifting out each
time, and drain. Depending on the type of
greens you have, cooking time varies:
spinach 3-10 minutes; beet tops 5-15
minutes; chicory, escarole, and lettuce
15-20 minutes; collards 10-15 minutes; Swiss
chard and mustard greens 15-20 minutes;
turnip greens and kale 15-25 minutes.
Greens can
also be cooked in the microwave. Place the
greens with just the water that clings to
the leaves in a 3-quart glass casserole.
Cover and microwave 6 minutes; stir. Cover
and microwave 6 minutes longer; stir. Cover
and microwave until tender, 3-6 minutes
longer. Let stand 1 minute, drain. |
Where
can I get more information? |
More
information on AREDS is available from the
National Eye Institute, www.nei.nih.gov
You can also
get trustworthy information from the
American Academy of Ophthalmology's partner
Web site, www.medem.com |
|
|
|
|
|
|
|
