Overview
Three different herbs are commonly called ginseng: Asian or Korean ginseng (Panax ginseng), American ginseng (P. quinquefolius), and Siberian ginseng (Eleutherococcus senticosus). The latter herb, however, is actually not ginseng.
Asian ginseng is a perennial herb with a taproot resembling the shape of the human body. It grows in northern China, Korea, and Russia; its close relative, P. quinquefolius, is cultivated in the United States. Because ginseng must be grown for five years before it is harvested, it commands a high price, with top-quality roots easily selling for more than ten thousand U.S. dollars. Dried, unprocessed ginseng root is called white ginseng, and steamed, heat-dried root is red ginseng. Chinese herbalists believe that each form has its own particular benefits.
Ginseng is commonly regarded as a stimulant. According to persons who use it
seriously, however, this description is inadequate. In traditional Chinese
herbology, P. ginseng was used to strengthen
the digestion and the lungs, to calm the spirit, and to increase overall energy.
Before World War II, a Russian scientist named Israel I. Brekhman became
interested in the herb and came up with a new way to describe it: as an
adaptogen.
An adaptogen is part of a hypothetical treatment that helps the body adapt to stresses of various kinds, whether heat, cold, exertion, trauma, sleep deprivation, toxic exposure, radiation, infection, or psychological stress. Furthermore, an adaptogen, by definition, should cause no side effects, should be effective in treating a wide variety of illnesses, and should help return an organism toward balance.
Perhaps the only indisputable example of an adaptogen is a healthful lifestyle. By eating right, exercising regularly, and generally living a life of balance and moderation, a person can increase physical fitness and the ability to resist illnesses of all types. Whether there are any substances that can do as much remains unclear. Brekhman believed that ginseng produced similarly universal benefits.
Traditional
Chinese medicine does not align with Brekhman’s idea. There
is no one-size-fits-all in Chinese medical theory. Like any other herb, ginseng is
said to be helpful for those people who need its particular effects and to be
neutral or harmful for others. In Europe, Brekhman’s concept took hold, and
ginseng is now widely believed to be a universal adaptogen.
Therapeutic Dosages
The typical recommended daily dosage of P. ginseng is 1 to 2 grams (g) of raw herb or 200 mg daily of an extract standardized to contain 4 to 7 percent ginsenosides. In one study of American ginseng for diabetes, the dose used was 3 g daily.
There are dozens of ginsenosides in ginseng. Because different ginsenosides have different effects, two different ginseng products with similar total ginsenoside content will not necessarily have similar efficacy. Scientific knowledge does not allow experts to make informed recommendations on which specific ginsenosides are useful for which conditions.
Ordinarily, a two- to three-week period of using ginseng is recommended, followed by a one- to two-week “rest” period. Russian tradition suggests that ginseng should not be used by those persons younger than age forty years. However, there is no scientific evidence to support these recommendations.
Therapeutic Uses
If Brekhman was right, ginseng should be the right treatment for the stresses of modern life. Ginseng is widely used for this purpose in Russia and Eastern Europe. However, the scientific basis for this use is largely limited to animal studies and human trials of unacceptably low quality.
There have been a few better-quality studies of various forms of ginseng for certain more specific purposes, such as strengthening immunity against colds and flu and other infections (including herpes), helping to control diabetes, stimulating the mind, increasing a general sense of well-being, and improving physical performance capacity. Some of these studies have found positive results with the use of ginseng.
The active ingredients in ginseng are believed to be substances called ginsenosides. Ginseng low in ginsenosides may not be effective. However, different ginsenosides appear to have differing actions, and the exact mixture of the ginsenosides in a given ginseng product may play a large role in its efficacy.
Two preliminary studies suggest that Korean red ginseng may have some benefits for impotence (erectile dysfunction). A poorly designed study using an untreated control group found indications that P. ginseng might improve sperm count and motility, thereby enhancing male fertility.
Highly preliminary evidence suggests that P. quinquefolius might improve the effectiveness of breast cancer chemotherapy drugs. P. ginseng also is said to help prevent cancer and to fight chemical dependency, but the scientific evidence for these uses is minimal at best. Another study failed to find ginseng helpful for menopausal symptoms.
Scientific Evidence
Adaptogenic effects. Numerous studies have evaluated the effects
of oral P. ginseng on animals under conditions of extreme stress.
The results suggest that ginseng increases physical endurance and causes
physiological changes that may help the body adapt to adverse conditions. In
addition, studies in mice found that consuming P. ginseng before
exposure to a virus significantly increased the survival rate and the number of
antibodies produced. However, most of these studies fall far
beneath modern scientific standards.
Colds and flu. A double-blind, placebo-controlled study of 323 people found meaningful evidence that an extract of American ginseng taken at 400 milligrams (mg) daily may help prevent the common cold. Participants who used the extract for four months had a reduced number of colds compared with those taking the placebo. Comparative benefits also were seen in the percentage of participants who developed two or more colds and in the severity and duration of cold symptoms that did develop. Similar benefits were seen in a study of forty-three people.
In addition, two double-blind, placebo-controlled studies indicate that P. quinquefolius may be able to prevent flulike illness in the elderly.
A double-blind, placebo-controlled study suggests that ginseng can also help
prevent flulike illnesses. This trial enrolled 227 participants at three medical
offices in Milan, Italy. One-half were given ginseng at a dosage of 100 mg daily,
the other one-half placebo. Four weeks into the study, all participants received
influenza
vaccine. The results showed a significant decline in the
frequency of colds and flu in the treated group compared with the placebo group
(fifteen versus forty-two cases, respectively). Also, antibody measurements in
response to the vaccination rose higher in the treated group than in the placebo
group.
On a much more theoretical level, two other studies found evidence that ginseng increases the number of immune cells in the blood, while a third study did not find this effect. (In any case, measuring changes in the number of immune cells is not a reliable method of demonstrating immune-system enhancement.) Also, a nonblinded pilot study provides weak evidence that ginseng might be helpful in chronic bronchitis.
Diabetes. In preliminary double-blind studies performed by a single research group, the use of American ginseng (P. quinquefolius) appeared to improve blood sugar control. In some studies, the same researchers reported potential benefit with Korean red ginseng.
A different research group tested ordinary ginseng and claimed to find it effective. However, this study was somewhat substandard in both its design and its reporting. In other studies, ordinary ginseng seemed to worsen blood sugar control rather than improve it, while yet another group found benefits. It appears possible that certain ginsenosides (found in high concentrations in some American ginseng products) may lower blood sugar, while others (found in high concentration in some P. ginseng products) may raise it. It has been suggested that because the actions of these various constituents are not well defined, ginseng should not be used to treat diabetes until more is known.
Mental function. Several studies have found indications that P. ginseng might enhance mental function. However, the specific benefits seen have varied considerably from trial to trial, tending to make the actual cognitive effects of ginseng (if there are any) difficult to discern. A double-blind, placebo-controlled study found that P. ginseng can improve some aspects of mental function. For two months, 112 healthy, middle-aged adults took either ginseng or placebo. The results showed that ginseng improved abstract thinking ability. However, there was no significant difference between the two groups in reaction time, memory, concentration, or overall subjective experience.
Another double-blind, placebo-controlled study of fifty men found that an eight-week treatment with a P. ginseng extract improved ability in completion of a detail-oriented editing task. Also, a double-blind trial of sixteen healthy males found favorable changes in ability to perform mental arithmetic in those given P. ginseng for twelve weeks.
A double-blind, placebo-controlled trial of sixty elderly people found that fifty or one hundred days of treatment with P. ginseng produced improvements in numerous measures of mental function, including memory, attention, concentration, and ability to cope. Benefits were still evident at the fifty-day follow-up. However, virtually no improvement was seen in the placebo group, a result that is highly unusual and raises doubts about the accuracy of the study. In addition, three double-blind, placebo-controlled studies evaluated combined treatment with P. ginseng and ginkgo and found some evidence of improved mental function.
Sports performance. The evidence for P. ginseng as a sports supplement is mixed at best. An eight-week, double-blind, placebo-controlled trial evaluated the effects of P. ginseng with and without exercise in forty-one persons. The participants were given either ginseng or placebo, and then they underwent exercise training or remained untrained throughout the study. The results showed that ginseng improved aerobic capacity in persons who did not exercise but offered no benefit in those who did exercise. In a nine-week, double-blind, placebo-controlled trial of thirty highly trained athletes, treatment with P. ginseng alone or in combination with vitamin E produced significant improvements in aerobic capacity. Another double-blind, placebo-controlled trial of thirty-seven persons also found some benefit.
A double-blind, placebo-controlled study of 120 people found that P. ginseng gradually improved reaction time and lung function in a twelve-week treatment period among those persons forty to sixty years old. No benefits were seen in younger persons.
However, numerous studies have failed to find P. ginseng effective. For example, an eight-week double-blind trial that followed sixty healthy men in their twenties found no evidence of ergogenic benefit. Many other small trials of P. ginseng also failed to find evidence of benefit.
General well-being. A double-blind study compared the effects of a nutritional supplement with and without P. ginseng extract on the feeling of well-being in 625 people whose average age was just under forty years. Quality of life was measured by a set of eleven questions. People taking the ginseng-containing supplement reported significant improvement compared with those taking the supplement without ginseng (the control group). Similar findings were reported in a double-blind, placebo-controlled study of thirty-six people newly diagnosed with diabetes. After eight weeks, participants who had been taking 200 mg of ginseng daily reported improvements in mood, well-being, vigor, and psychophysical performance that were significant compared with the reports of control participants.
A twelve-week, double-blind, placebo-controlled study of 120 people found improvement in general well-being among women aged thirty to sixty years and men aged forty to sixty years, but not among men aged thirty to thirty-nine years.
However, a double-blind, placebo-controlled trial of thirty young people found marginal benefits at four weeks and no significant benefits at eight weeks. Similarly, a sixty-day, double-blind, placebo-controlled trial of eighty-three adults in their mid-twenties found no effect on mood or psychological well-being.
A double-blind study of fifty-three people undergoing cancer treatment found equivocal evidence of benefit with a special form of ginseng modified to contain higher levels of certain constituents.
Impotence (erectile dysfunction). Two double-blind, placebo-controlled trials, involving a total of about 135 people, have found evidence that Korean red ginseng may improve erectile function. In the better of the two trials, 45 participants received either placebo or Korean red ginseng at a dose of 900 mg three times daily for eight weeks. The results indicate that while using Korean red ginseng, men experienced significantly better sexual function than while they were taking placebo.
In an analysis combining the results of six controlled trials, researchers found some evidence for the benefits of Korean red ginseng. However, the small size and generally low quality of the studies left some doubts about this conclusion.
Preventing cancer. An observational study on ginseng and cancer prevention has been widely publicized, but a close look at the data arouses serious suspicions. This study was performed in South Korea and followed a total of 4,587 men and women aged thirty-nine years and older from 1987 to 1991. People who regularly consumed P. ginseng were compared with otherwise similar people (matched in gender, age, alcohol use, smoking, education, and economic status) who did not.
The reported results were impressive. Those who used ginseng showed a 60 percent decrease in risk of death from cancer. Lung cancer and gastric cancer were particularly reduced. The more ginseng consumed, the greater the effect.
However, there is something not right about this study. The use of ginseng fewer than three times per year reportedly led to a 54 percent reduction in risk. It is difficult to believe that so occasional a use of ginseng could reduce cancer mortality by more than one-half.
Menopause. A double-blind, placebo-controlled study of 384 women experiencing menopausal symptoms found no significant benefit with P. ginseng and no evidence of hormonal effects.
Safety Issues
Ginseng appears to be nontoxic, both in the short term and the long term, according to the results of studies in mice, rats, chickens, and dwarf pigs.
Reported side effects in humans are rare. There are a few case reports of
breast tenderness, postmenopausal vaginal bleeding, and menstrual abnormalities
associated with P. ginseng use. Such side effects suggest that it
has estrogenic properties. However, a large double-blind trial of P.
ginseng found no estrogen-like effects. Another double-blind trial
found no effects on estrogen or testosterone,
and a carefully designed test-tube study showed that ginseng is not estrogenic.
Therefore, it is possible that these apparent side effects were coincidental;
another possibility is that adulterants in the ginseng product used caused the
problem. Ginseng and other Asian herbal products have often been found to contain
unlisted herbs and pharmaceuticals.
Estrogen itself stimulates the growth of breast cancer cells. In a test-tube study, P. ginseng was again found to be nonestrogenic, and yet, it nonetheless stimulated the growth of breast cancer cells. Although the mechanism of this effect is not known, the results suggest that women who have had breast cancer should avoid using ginseng.
Unconfirmed reports suggest that highly excessive doses of P. ginseng can cause insomnia, can raise blood pressure, can increase heart rate, and can cause other significant effects. Whether some of these cases were actually caused by caffeine mixed in with ginseng remains unclear. One double-blind study failed to find any effect on blood pressure.
One case report and one double-blind trial suggest that P.
ginseng can reduce the anticoagulant effects of Coumadin
(warfarin), but another trial failed to find such an
interaction. The reason for this discrepancy is not clear, so one should not
combine ginseng and warfarin.
Two reports indicate that combination treatment with P.
ginseng and antidepressant drugs may result in a
manic episode. There are also theoretical concerns regarding the use of ginseng by
people with diabetes. If it is true, as the foregoing preliminary studies suggest,
that ginseng can reduce blood sugar levels, people with diabetes who take ginseng
might need to reduce their dose of medication. On the other hand, if certain types
of ginseng have the opposite effect (as researchers hypothesize), this could
necessitate an increase in medication. People with diabetes should use ginseng
only under physician supervision.
In 1979, an article in the Journal of the American Medical Association claimed that people can become addicted to P. ginseng and can develop blood pressure elevations, nervousness, sleeplessness, diarrhea, and hypersexuality. However, this report has since been thoroughly discredited and should no longer be taken seriously.
Chinese tradition suggests that P. ginseng should not be used by pregnant or nursing women, and one animal study hints that ginseng use by a pregnant woman could cause birth defects. Safety in young children or in persons with severe liver or kidney disease has not been established.
Important Interactions
In persons taking antidepressants, P. ginseng might cause manic episodes. For persons using insulin or oral hypoglycemics, various forms of ginseng may unpredictably alter the dosage need. For persons taking Coumadin, P. ginseng might possibly decrease its effect. However, P. ginseng might increase the effectiveness of the influenza vaccine.
Bibliography
Ellis, J. M., and P. Reddy. “Effects of Panax ginseng on Quality of Life.” Annals of Pharmacotherapy 36 (2002): 375-379.
Hartz, A. J., et al. “Randomized Controlled Trial of Siberian Ginseng for Chronic Fatigue.” Psychological Medicine 34 (2004): 51-61.
Jang, D. J., et al. “Red Ginseng for Treating Erectile Dysfunction.” British Journal of Clinical Pharmacology 66 (2008): 444-450.
Kim, J. H., C. Y. Park, and S. J. Lee. “Effects of Sun Ginseng on Subjective Quality of Life in Cancer Patients.” Journal of Clinical Pharmacy and Therapeutics 31 (2006): 331-334.
Predy, G. N., et al. “Efficacy of an Extract of North American Ginseng Containing Poly-Furanosyl-Pyranosyl-Saccharides for Preventing Upper Respiratory Tract Infections.” CMAJ 173 (2005): 1043-1048.
Reay, J. L., D. O. Kennedy, and A. B. Scholey. “The Glycaemic Effects of Single Doses of Panax ginseng in Young Healthy Volunteers.” British Journal of Nutrition 96 (2006): 639-642.
Vuksan, V., and J. L. Sievenpiper. “Herbal Remedies in the Management of Diabetes: Lessons Learned from the Study of Ginseng.” Nutrition, Metabolism, and Cardiovascular Diseases 15 (2005): 149-160.
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