TUESDAY, Aug. 13, 2002 (HealthDayNews) -- Senior citizens who take multivitamin supplements and extra doses of vitamin E may be getting less than they bargained for when it comes to protection from respiratory infections.
A new study by Dutch researchers has found that vitamin pills don't protect the elderly against illnesses such as bronchitis and pneumonia, as previously suggested. What's more, daily vitamin E supplements may even make the infections that do occur more severe.
The study appears in tomorrow's Journal of the American Medical Association.
Vitamin E is abundant in vegetable oils, nuts and green leafy vegetables. A survey in 2000 showed that more than 37 million Americans take vitamin E supplements, many with the hope that the potent antioxidant will reduce their risk of heart trouble.
However, studies have failed to find consistent evidence of such a benefit, or other positive effects, from the nutrient. Earlier this summer, for example, Australian scientists reported that high doses of vitamin E failed to protect older people from developing macular degeneration, a leading cause of blindness, or from stalling progression of the condition once it's under way.
But Cheryl Rock, a nutrition expert at the University of California, San Diego, said studies of vitamin E often suffer from methodological problems that make their conclusions sketchy.
The nutrient appears to act on a long time scale, perhaps five years, she said, so trials that don't last that long may underestimate its powers. And it's not very well absorbed by the body, so if the doses aren't high enough, whatever benefits it has may not appear.
Previous research has suggested that vitamin E may guard against infections in the elderly by stimulating their immune systems. In the new study, scientists at Wageningen University in the Netherlands sought to learn if vitamin supplements, including vitamin E, really do boost immunity in relatively healthy people.
They followed 652 men and women age 60 and older who weren't living in nursing homes and related facilities. Half were given multivitamins with or without 200 milligrams of vitamin E, one-quarter took vitamin E alone, and the rest received sugar tablets.
During an average follow-up of about 15 months, two-thirds of the subjects reported developing a total of 1,024 respiratory infections, such as bronchitis and pneumonia. But neither the incidence nor the severity of these ailments depended on whether the patients had been taking vitamins.
But the two groups that received vitamin E supplements were more likely to suffer longer infections with more symptoms, including fever, than those in the other two groups, the researchers said.
"If our results are confirmed and vitamin E exacerbates respiratory tract infections, elderly people, especially those who are already well-nourished, should be cautious about taking vitamin E supplements," the researchers wrote. Only a small fraction of the participants in the study had vitamin deficiencies.
Yet Dr. Simin Nikbin Meydani, a Tufts University vitamin E expert familiar with the Dutch findings, said she's not convinced the nutrient was making infections worse. The elderly tend to lose their ability to generate fevers in response to infection. So, the fact that those who received the substance had higher temperatures might be a good thing, she said.
In addition, Meydani said, the volunteers who took vitamin E were slightly more likely to be smokers, and to have obstructed lungs and asthma than the other subjects. While these differences weren't statistically significant, "when you add them up they could do something," she said.
Meydani and her colleagues are conducting a similar study with nursing home residents that she hopes will answer the question of whether vitamin E prevents infections. They expect to have results in a year.
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