Long-term, regular use of vitamins E and C has no apparent effect on the risk of age-related cataract in men, according to a report in the November issue of Archives of Ophthalmology.
"An estimated 20.5 million persons 40 years and older in the United States show some evidence of age-related cataract," the authors write as background information in the article. "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 cataract."
To evaluate the effects of vitamin E and vitamin C on cataracts, William G. Christen, Sc.D., from Brigham and Women's Hospital and Harvard Medical School, Boston, and colleagues studied 11,545 apparently healthy U.S. male physicians 50 years and older. Men were randomly assigned to receive vitamin E or placebo and vitamin C or placebo. Those in the vitamin E group received 400 international units (IU) of vitamin E daily or placebo and those in vitamin C group received 500 milligrams of vitamin C on alternate days or placebo. After an average of eight years of treatment and follow-up, 1,174 cataracts and 801 cataract extractions (surgery to remove cataract and repair the eye lens) were confirmed.
There were 579 cataracts in the vitamin E treatment group and 595 cataracts in the placebo group. Analyses of the effects of vitamin E on cataract subtypes indicated no significant effects of the treatment on nuclear, cortical or posterior subcapsular cataract. The authors determined that "there was no apparent benefit of vitamin E at any point during the trial."
In the vitamin C segment, there were 593 cataracts in the group receiving treatment and 581 in the placebo group. Similar non-significant findings were observed for each of the three cataract subtypes. Additionally, the authors found 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."
Explore further: Conceptual confusion among researchers of value-based health care
More information: Arch Ophthalmol. 2010;128:1397-1405.