Vitamin & Mineral Supplements

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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