Six-year vitamin E supplementation decreased mortality by 41% in elderly male smokers who had high dietary vitamin C intake, but increased mortality by 19% in middle-aged smokers who had high vitamin C intake, according to a study published in the American Journal of Epidemiology.

Large-scale controlled trials have not found any overall effects of vitamin E supplementation on the mortality of participants. Nevertheless, the effect of vitamin E on respiratory infections has significantly diverged between different population groups suggesting that the effects of vitamin E may not be uniform over all the population.

Dr. Harri Hemila, and Professor Jaakko Kaprio, of the University of Helsinki, Finland, studied whether the effect of vitamin E supplementation on mortality might diverge between different population groups. They analyzed the data of the large randomized trial (Alpha-Tocopherol Beta-Carotene Cancer Prevention Study) which was conducted in Finland between 1985-1993 and included male smokers aged 50-69 years. There were 3571 deaths in 29,133 participants during the 6-year supplementation of 50 mg/day of vitamin E.

Although vitamin E had no overall effect on mortality, its effect was modified by age and dietary vitamin C intake. Vitamin E had no effect on participants who had low dietary vitamin C intake, less than 90 mg/day. However, in those who had high vitamin C intake, over 90 mg/day, the effect of vitamin E diverged so that it increased mortality in young participants (50-62 years), but decreased mortality in old participants (66-69 years).

The US nutritional recommendations, issued by the prestigious Institute of Medicine, consider that vitamin E is safe in doses up to 1000 mg/day. This new study gives further evidence indicating that in some population groups vitamin E may be harmful in a substantially lower dose, 50 mg/day.

The researchers concluded that “in people younger than 65 years, taking vitamin E supplements should be strongly discouraged, until clear evidence emerges that some population groups of younger or middle-aged people benefit”. They also concluded that the effect of vitamin E on elderly people should be further investigated.

Harri Hemilä and Jaakko Kaprio: Modification of the Effect of Vitamin E Supplementation on the Mortality of Male Smokers by Age and Dietary Vitamin C. American Journal of Epidemiology Advance Access published online on February 13, 2009

Helsingin yliopisto (University of Helsinki)
helsinki.fi