Supplements May Prevent
Age-Related Vision Loss

NEW YORK (Reuters Health) - A dietary supplement containing high levels of certain vitamins and minerals appears to lower the risk of blindness in some elderly individuals, according to a national study released Friday.

However, the same supplements did not reduce the risk of developing cataracts, a clouding of the lens of the eye that can occur with age, a related study reports.

Individuals at high risk of age-related macular degeneration (AMD) who took a high-dose combination of vitamins C and E, beta-carotene and the mineral zinc lowered their risk of the disease by 25%. The supplements had no apparent effect on those who were not at risk, researchers report in the October issue of Archives of Ophthalmology.

AMD, the leading cause of blindness in elderly Americans, occurs when abnormal blood vessels leak fluid and blood into the tissue at the back of the eye, leading to blistering and scarring of the retina. The disease affects central vision needed for reading, driving and recognizing faces, but patients are often able to detect colors and see with their peripheral vision. There is no cure for AMD.

While the supplements did not restore vision that had already been lost, they slowed the progression of vision loss in some individuals with intermediate or advanced AMD. These individuals ``should consider taking a supplement of antioxidants plus zinc,'' according to the researchers from the Age-Related Eye Disease Study Research Group.

Dr. Lee M. Jampol, an ophthalmologist from Northwestern University in Chicago, Illinois, recommends that patients of any age who show advancing signs of macular degeneration consider taking a similar supplement. While the current study did not determine an optimal length of treatment, ``it seems desirable that this supplement should be taken indefinitely,'' he writes in an editorial accompanying the article.

In the study, more than 3,600 people aged 55 to 80 years at risk for AMD received a daily dietary supplement. The supplement consisted of either 500 milligrams (mg) of vitamin C, 400 international units of vitamin E and 15 mg of beta-carotene; 80 mg of zinc and 2 mg of copper; antioxidants and zinc; or an inactive pill (placebo).

Study participants at high risk of developing vision loss associated with AMD who took antioxidants and zinc were less likely than those who took only antioxidants or only zinc to lose their vision over the 6-year study. Individuals who took a placebo were the most likely to develop advanced AMD and vision loss.

Even among those who took a daily multivitamin in addition to the assigned supplement, the high-dose supplement was associated with a decreased risk of vision loss. Although the nutrients found in the supplements occur naturally in many foods, sufficient levels may be difficult to obtain through diet alone.

However, individuals should consult their doctor before taking high doses of any nutrient, the researchers note. Doses used in the study were 5 to 15 times the recommended dietary allowance and may have unintended effects in some individuals such as kidney stones (vitamin C), muscle weakness and fatigue (vitamin E), anemia and upset stomach (zinc), and yellow skin (beta carotene).

In a related study, the supplements did not reduce the risk of cataracts in the same group of patients over 7 years.

The research was funded by the National Eye Institute, which is part of the National Institutes of Health. Bausch & Lomb provided the supplements used in the studies. Individual researchers have no financial stake in the supplements used in the study.

SOURCE: Archives of Ophthalmology 2001;119:1417-1436, 1439-1452, 1533-

Reference Source 89

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