WASHINGTON — Vitamin E pills reduced prostate cancer risk by a third and the disease's death rate by 41% in a study of thousands of smokers, researchers report. The same study, in Finland, found that a form of vitamin A had no effect on reducing cancer.
"There may be a pattern developing of some kind of broad cancer preventive effect from vitamin E," said Dr. Demetrius Albanes, a National Cancer Institute researcher and co-author of the study.
A report on the research will be published today in the Journal of the National Cancer Institute.
Albanes said that although both vitamin E and beta carotene, the form of vitamin A used in the study, are antioxidants, only vitamin E appears to give a statistically significant protection against cancer.
In fact, said Albanes, the data suggest that beta carotene users in the study were about 16% more likely to develop lung cancer. This result, first reported three years ago, startled many researchers, who had expected beta carotene to be proved as a cancer preventive.
Albanes said detailed analysis of the study shows that vitamin E, in the form of alpha tocopherol, provides some protection against colon-rectal cancer and lung cancer, although these data are not as dramatic as the prostate cancer results.
Albanes participated in the study with researchers from the University of Helsinki, Finland.
Dr. Ishwarlal Jialal, a researcher at the University of Texas, Southwestern Medical Center, in Dallas, said the study "is a very significant observation" but "needs to be confirmed by another group study, especially among nonsmokers."
The vitamin E dosage was 50 mg a day, which is the equivalent of 50 international units. This is about five times the recommended minimum daily intake for men, said Albanes, and about 2 1/2 times what most people get from food.