Tuberculosis risk in smokers with Vitamin E

The use of vitamin E supplements appears to increase the risk of tuberculosis in some middle-aged smokers.Vitamin E is a widely used dietary supplement believed to enhance immune function. However, trials in human subjects have shown unpredictable effects of vitamin E on various infectious diseases.To examine the impact of vitamin E or beta-carotene use on the risk of tuberculosis, Finnish researchers analysed data from 29,023 male smokers, ages 50 to 69 years, who were randomly assigned to take daily supplements containing vitamin E, beta-carotene, vitamin E plus beta-carotene, or an inactive placebo. During a follow-up period of around 6 years, 174 cases of tuberculosis were diagnosed. Overall, neither vitamin E nor beta-carotene supplements affected the risk of tuberculosis. However, the combination of smoking 20 or more cigarettes per day and consuming a diet rich in vitamin C and vitamin E supplements increased the risk of tuberculosis by 72%. Further analysis showed that the increased risk was restricted to the first year after vitamin E supplementation began.Although vitamin E may be beneficial in restricted population groups, those groups are poorly defined so far. Vitamin E increasing the risk of tuberculosis in heavy smokers with a high dietary vitamin C intake should make us cautious about taking vitamin E supplements to improve the immune system.