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Vitamin E may help prevent cataracts.

Vitamin E May Help Prevent Cataracts

LA GRANGE, ILLINOIS: The statistics on cataracts are staggering. Among Americans age 60 to 75,20 percent have visually disabling cataracts. The cost of treating cataracts is soaring, too. Individuals are spending about $3.5 billion a year in cataract removal. Cataracts are the third leading cause of blindness, afflicting 400,000 people annually.

Faced with these numbers and the aging of our population, researchers are stepping up efforts to prevent cataracts or at least delay their onset.

Recent studies suggest that the risk of developing cataracts may be reduced by daily intake of vitamin E.

Two Canadian researchers report that vitamin E - in its role as an antioxidant - may help to prevent cataract formation.

Dr. James Robertson of the University of Western Canada compared the intake of antioxidant vitamins by 175 cataract patients and a like number of cataract-free individuals.

He found that the cataract-free group took significantly more vitamin E than the cataract patients and that individuals who took vitamin E supplements experienced a 56 percent decrease in cataract risk.

Robertson's colleague, Dr. John Trevithick, found that the addition of high levels of vitamin E to the diets of diabetic rats (who are especially prone to develop cataracts) reduced the leakage of lens protein into the fluids surrounding the eye, one of the indications of cataract formation.

What Causes Cataracts?

The function of the lens is to focus rays of light on the retina. In order for the process to produce a sharp image, the lens must be transparent. When a cataract, which is a clouded region in the lens of the eye, is present, light is scattered and vision becomes blurred. For at least half the population over age 65, cataracts are a problem.

There are several causes and forms of cataracts. The most common form is senile cataract, often the result of oxidative damage caused by free radicals.

Exposure to radiation ranging from X-rays to ultraviolet radiation from the sun causes formation of highly reactive chemical fragments in the eye. These fragments are called free radicals.

Free radicals attack the structural proteins, enzymes, and membranes in the cell of the eye's lens. The body's natural defenses against this free radical attact are antioxidants and enzymes. Over time, these defenses become vulnerable and oxidative damage accumulates. Accumulated oxidative damage is thought to be one of the prime causes of cataracts in older people.

Vitamin E in Cataract Prevention

Vitamin E is the major fat-soluble antioxidant that protects cells against free radical/oxidative damage.

Dr. G. Edwin Bunce and Dr. John Hess of Virginia Polytechnic Institute report in Nutrition Today (11/88) that "the presence of liberal quantities of vitamin E can diminish oxidative damage" in the lens.

Bunce and Hess subscribe to the view that chronic levels of oxidative damage in cellular membranes generally can be "ameliorated by supplementation with vitamin E."

Even though most cataracts occur later in life, Bunce and Hess say there is little doubt that oxidation, "especially at the lens cell membrane, is an early event in the genesis of most senile cataracts."

While no one contends that cataracts in the elderly can always be prevented, researchers believe that oxidative damage can be controlled by habits adopted earlier in life.

For some, this may mean the use of ultraviolet-absorbing sunglasses and wearing a brimmed hat. Others believe in the benefits of vitamin supplementation. Bunce and Hess suggest that since cataracts "require years of maturation," a moderate supplement of vitamin E - up to 400 International Units daily - may delay the onset and slow the advance of them."
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Publication:Nutrition Health Review
Date:Jun 22, 1989
Words:599
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