(RxWiki News) A recent study from Harvard Medical School finds that vitamins C and E appear to do little to influence the development or outcome of age-related cataracts.
An estimated 20.5 million individuals over age 40 in the United States show evidence of developing cataracts, part of which is caused by oxidative damage. Because of this oxidative-damage causal link, researchers have focused on the associations between dietary antioxidants, especially vitamins C and E, and the risk of cataracts.
To evaluate this possible antioxidant effect, researchers William G. Christen, Sc.D., from Brigham and Women's Hospital and Harvard Medical School, Boston, and colleagues looked at 11,545 seemingly healthy U.S. male physicians 50 years and older. These men were assigned to receive vitamin E, vitamin C or a placebo (two control groups -- one for each vitamin group).
After an average eight-year follow-up, researchers confirmed 1,174 cataracts and 801 cataract extractions. Among the vitamin E group, there were 579 cataract cases and 595 cases in the control group. For the vitamin C group, there were 593 cataracts and 581 among the vitamin C placebo group.
The authors noted "no apparent benefit of vitamin E at any point during the trial," and, among the vitamin C groups, they found only a "possible, but statistically non-significant" trend toward increased cataract risk factors in those with a history of cardiovascular disease.
The authors concluded vitamins E and C have little effect on rates of cataract diagnosis and extraction.
Cataracts are a clouding that develop in the crystalline lens (or its envelope) in the eye. They vary from slight to complete opacity and obstruct the passage of light. One eye is usually affected before the other. The condition can cause blindness if left untreated.
"Like most conditions, cataract formation is likely the result of multiple factors," said Dr. Christopher Quinn, president of Omni Eye Services. "This study fails to find a link between Vitamin E and Vitamin A supplements and the subsequent diagnosis of cataract."
Quinn said further study is warranted since early cataract formation "likely occurs over a patient's entire lifetime (not just after the age of 50) and any benefit of vitamins may occur over longer periods of time."