However, the study, published in the British Journal of Nutrition, also found vitamin E had no effect on those who had low dietary vitamin C intake.

"The consumption of vitamin E supplements by the general population should be discouraged because there is evidence of harm for some people," University of Helsinki researchers said in a statement.

Dr. Harri Hemila and Dr. Jaakko Kaprio of the University of Helsinki set out to study whether vitamin E supplementation could decrease the risk of tuberculosis. They analyzed the data of the randomized trial -- Alpha-Tocopherol Beta-Carotene Cancer Prevention Study -- which was conducted in Finland from 1985-93 and included male smokers ages 50 to 69 years.

There were 174 cases of tuberculosis in 29,023 participants during the six-year supplementation of 50 mg/day vitamin E.

Unexpectedly, vitamin E supplementation increased tuberculosis risk in those whose with a dietary vitamin C intake more than 90 mg/day. The most dramatic increase in tuberculosis risk by vitamin E was restricted to a one-year period after the initiation of supplementation.