Vitamin E supplementation may decrease or increase, or may have no effect, on the risk of pneumonia depending on the level of smoking and leisure time exercise, according to a study.
In laboratory studies, vitamin E has influenced the immune system. In several animal studies vitamin E protected against viral and bacterial infections. However, the importance of vitamin E on human infections is not known.
Dr. Harri Hemila and Professor Jaakko Kaprio, of the University of Helsinki, Finland, studied the effect of vitamin E on the risk of pneumonia in the large randomized trial (Alpha-Tocopherol Beta-Carotene Cancer Prevention Study), which was conducted in Finland between 1985-1993. There were 898 cases of pneumonia among 29,133 participants of the study.
Over half of the participants were outside of these two subgroups and vitamin E did not affect their risk of pneumonia. Thus, the beneficial and harmful effects of vitamin E are restricted to fairly small parts of the population.
The researchers concluded the role of vitamin E in susceptibility to pneumonia in physically active nonsmokers warrants further study.
The study has been published in Clinical Epidemiology.