Ginseng May Enhance Immune Function
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.
Most of the side effects reported with Korean ginseng, such as high blood pressure, diarrhea, insomnia, and dizziness, have been reported in people who took very high doses -- some as high as 15 grams per day. This is well above recommended daily dose of 0.5 to 2 grams a day, Mahady and her colleagues write. A few cases of estrogenic-like side effects in pre- and postmenopausal women also have been recorded. The reports of side effects are hard to evaluate because they offer few, if any, details regarding the exact doses taken, or species of ginseng.
Siberian ginseng has been associated with high blood pressure and abnormal heart rhythm, and with low blood sugar in people with diabetes. Because good safety data are lacking, the authors do not recommend either form of ginseng for children or for pregnant or lactating women.
Unfortunately, labels are not always accurate, Mahady says, and it is hard for consumers to be certain how much ginseng actually is in the products they use.
Mahady urges people to learn as much as possible about the supplements they take and recommends a healthy dose of skepticism if a trial showing beneficial effects of ginseng happens to be sponsored by a company that manufactures it.
"I don't think ginseng is going to do anything for [people who are already healthy]," she says. "But it may help a patient with a chronic illness, as long as they don't have diabetes or high blood pressure."
- Although ginseng has been touted to improve physical endurance in healthy people, scientific evidence does not support this claim.
- Studies have shown that ginseng can be beneficial as an immune system boost in people with chronic illness.
- Taken in very high doses, ginseng can have negative side effects, such as high blood pressure, diarrhea, insomnia, and dizziness.