Saturday, November 13, 2010

Vitamin C, E do not inhibit cataract formation: study

Vitamin C, E do not inhibit cataract formation: study







BOSTON: Researchers delving into the role of vitamins in cataract prevention have found that higher intakes of nutrients with antioxidants [compounds that protect against cell damage inflicted by molecules called oxygen-free radicals, which are a major cause of disease and aging.] especially vitamins C and E has little or no effect on the risk of the age-related eye problem in men.

Observational studies by nutrient experts have suggested that antioxidants [compounds that protect against cell damage inflicted by molecules called oxygen-free radicals, which are a major cause of disease and aging.] and certain vitamins have the potential to decrease cataracts and slow their advancement because they reduce oxidation damage to the lens.

Lead researcher, Dr. William G. Christen from Brigham and Women’s Hospital and Harvard Medical School, Boston stated, "Nutrition is suspected to be an important factor in cataract development.

"Because oxidative damage is a prominent feature of cataracts, one focus of nutrition research has been the link between dietary intake of nutrients with antioxidant potential, particularly vitamins E and C, and the risk of cataracts.”

According to experts, surgery is the only treatment to remove cataract, while adhering to diet rich in fruits and vegetables and not smoking may be effective in preventing the age related problem.

In order to examine the link between antioxidant vitamins and cataract formation the researchers followed 11545 healthy male doctors aged 50 and older.

None of the participants were diagnosed with cataract at the onset of the study.

As a part of the study, 5771 subjects were assigned to 400 IU of vitamin E and 5774 to vitamin E placebo every other day.

In addition, 5779 participants were given 500 mg of vitamin C and 5746 a vitamin C placebo daily.

A follow-up at eight years exhibited no significant benefit of vitamin supplementation in cutting the risk of cataract.

There were 801 cataract extractions and 1174 confirmed incidents of cataracts during the study period.

These included 593 cases of cataracts in the vitamin C group as opposed to 581 in the vitamin C placebo group.

In the vitamin E group 579 cataracts were reported compared to 595 in those assigned to the vitamin E placebo.

The authors stated that "the effect of vitamin C on cataract and extraction (removal) did not differ appreciably within categories of known or possible risk factors, other than a possible, but statistically non-significant trend toward increased risk in those with a reported history of cardiovascular disease.

"In summary, these randomized trial data from a large population of middle-aged and older, generally well-nourished men indicate that long-term supplementation with high-dose vitamin E and vitamin C, either alone or in combination, has little effect on rates of cataract diagnosis and extraction."

The findings have been reported in the November issue of 'Archives of Ophthalmology.'

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