Ginseng May Enhance Immune Function
June 5, 2000 -- Stop before you pop that ginseng tablet if
you're taking it to boost physical endurance. Ginseng seems to enhance certain
components of the immune system, but claims that it boosts physical endurance
in healthy people do not hold up, according to researchers at the University of
Illinois at Chicago.
The term "ginseng" has been applied to more than 30
different species of plants, lead author Gail B. Mahady, PhD, and her
colleagues write in a recent issue of Nutrition in Clinical Care. They
concentrated on the Korean and Siberian varieties because those have been the
focus of most previous studies.
Traditionally, Korean ginseng has been used as a tonic or
immune stimulant for people recovering from chronic illnesses. The current
practice of promoting it as a performance-booster in people who are already
healthy is a "terrible mistake," Mahady tells WebMD.
"It has been used in traditional Chinese medicine in people
more to restore health," she says. "It is never used in healthy
individuals." Most of the trials showing a beneficial effect of Korean
ginseng on physical endurance and capacity were so poorly performed that it is
difficult to draw any conclusions from them, she and her co-authors write.
More promising are studies of the effects of Korean ginseng on
the immune system. Two trials have shown that in healthy volunteers who take
ginseng, certain immune cells are more numerous or more active than in people
who take a placebo, or sugar pill.
For example, in a study of patients with bronchitis, a
congestive lung disease, ginseng appeared to enhance the function of certain
immune components in the bronchi, which are the main airways in the lungs.
Mahady and her co-authors suggest ginseng may exert its effects on the body's
stress response as well as the immune system.
There is some evidence that ginseng enhances immune activity in
patients with AIDS and chronic fatigue syndrome, says Mahady, who is a research
assistant professor at the university's College of Pharmacy. However, she tells
WebMD that no good studies have yet confirmed its effect. "We really need
to look at it in the elderly because there's a lot of chronic illness in that
group," she says.
Russians traditionally have used Siberian ginseng to increase
energy and decrease stress. However, most of the clinical trials suggesting
that Siberian ginseng has an effect were performed decades ago and, like the
studies of Korean ginseng, were poorly performed, the authors write. Because of
this, it is difficult to conclude what effect, if any, Siberian ginseng has on
endurance or physical performance. One study suggests that extracts of Siberian
ginseng increase the number of working cells in the immune system in healthy
volunteers when compared to people receiving a placebo.