Older men who supplement their diet with vitamin E might want to take note: researchers in Finland believe that it may be a double-edged sword.

Vitamin E has long been a popular supplement for older men because of how its beneficial effects skew. It helps decrease the risk of age-related macular degeneration, slows the functional declines associated with Alzheimer's disease, and lessens the harmful effects of medical treatments such as radiation and dialysis.

But the Finnish scientists learned that vitamin E supplementation increases the risk of pneumonia for over 1 in 4 older men who smoke and do not exercise. Conversely, vitamin E actually decreases the risk for pneumonia in oldsters who do exercise and don't smoke!

This is startling for a number of reasons, not least among which being that analyses in nutritional epidemiology usually assume a uniform effect of a nutrient. How you live your life shouldn't have any impact on the effects of the nutrients you consume.

The researchers examined the effect of vitamin E on the risk of pneumonia in a large randomized trial conducted in Finland between 1985 and 1993. There were 898 cases of pneumonia among 29,133 participants of the study.

Vitamin E increased pneumonia risk by 68 percent among men who had the highest exposure to smoking and who did not exercise (22 percent of the trial participants), while vitamin E actually reduced pneumonia risk by 69 percent among participants who had the least exposure to smoking and who exercised regularly (7 to 6 percent of the participants). The authors uphold that these findings refute there being one single effect of vitamin E supplementation on the risk of pneumonia.

The research throws a monkey wrench into the notion that the average effects of vitamin E – or perhaps any nutrient – that are calculated in meta-analyses may be valid for many population groups. Given the current limited understanding about who might benefit, the researchers recommend that vitamin E should not be suggested for the general population for improving the immune system. The authors conclude that there is a need for further research on vitamin E for non-smoking elderly men who exercise in their leisure time.