American
Ginseng (Panax Quinquefolius)
Herb
Description:
The American ginseng
plant, Panax quinquefolius, is similar in appearance and is in the
same botanic genus as Asian ginseng (panax ginseng). First described
in the early 18th century in Eastern Canada, P. quinquefolius was
primarily harvested for export to China. American ginseng is also
referred to as North American, Canadian, or Wisconsin ginseng, referring
to primary areas of harvest or cultivation, although it is now grown
in many areas of the world. The root is used medicinally.
Uses
and Benefits
Ginsengs are
marketed in the U.S. to boost energy, relieve stress, improve concentration,
and enhance physical or cognitive performance. Most ginsengs are
believed to act as general restoratives, tonics, or adaptogens,
which have nonspecific strengthening properties to restore the body's
balance, enhance stamina, and increase resistance to stress and
disease.
In traditional
Chinese medicine (TCM), Asian and American ginsengs are used to
restore vital energy in the body. However, American ginseng is considered
to have more cooling or calming qualities, as opposed to Asian ginseng's
more heating or stimulating properties. According to TCM theory,
American ginseng is used to calm the ailing respiratory or digestive
systems and as therapy for diabetes or "thirsty" syndromes,
and may be preferred in warmer climates.
Native Americans
traditionally employed American ginseng to help with childbirth
and fertility and to strengthen mental powers, and for a variety
of ailments such as respiratory disorders, headaches, and fevers.
Clinical
Trials:
There are few
controlled clinical trials using American ginseng products. In one
randomized, double-blind, placebo-controlled crossover study of
eight athletic volunteers, a noncommercial American ginseng extract
in a daily dose of 8 - 16 mg/kg for 7 days failed to enhance physical
performance as measured by a cycle ergometer. There were no significant
differences compared to placebo in any of the outcome measures,
which included oxygen uptake, heart rate, time to exhaustion, lactate
and glucose concentrations, and rating of perceived exertion.
In a series
of randomized, single-blind, placebo-controlled studies by
the same investigators, a single dose of American ginseng was found
to reduce post-prandial glycemia by about 10-20%. Effects were not
found to be dose dependent. In healthy subjects, 1-3 g doses reduced
glycemia when given at least 40 minutes before a glucose load. In
type-II diabetics, 3-9 g doses were tested and found to reduce glycemia
when given with, or up to 2 hours prior to, a glucose load.
Adverse
Effects:
No significant
adverse effects have been reported in the few clinical trials, and
there are no case reports of clinical toxicities. Due to similar
chemical constituents, American ginseng has the potential to cause
any of the side effects possible with Asian ginseng, which appear
to be uncommon and idiosyncratic.
Side Effects
and Interactions: No drug interactions are recognized.
Cautions:
One American
ginseng product has been shown to mildly blunt the hyperglycemic
effect of food; this may theoretically be detrimental in a tightly
controlled or labile diabetic. Unlike Asian ginseng products, adulteration
or contamination of American ginseng has not yet been reported.
Safety has not been established during pregnancy or breast feeding.
Preparations
& Doses:
American ginseng
is available in multiple forms, from whole root products to a variety
of more concentrated formulations and extracts in capsules, tablets,
liquids, teas, and foods. The crude root is usually taken in doses
of 1-2 g/day, but up to 9 g or more is used in traditional Chinese
medicine. Many formulations contain concentrated extracts or preparations
standardized to ginsenosides, usually as 100-200 mg of extract per
dose.
Summary
Evaluation:
American ginseng,
like Asian and Siberian ginseng, is traditionally used as a tonic
or adaptogen to enhance health and combat stress or disease. Few
clinical trials have been conducted. In one well-designed study,
American ginseng did not enhance physical performance. In another
series of studies, single doses of one product mildly attenuated
post-prandial glycemia; whether this effect is reproducible and
beneficial for diabetics awaits chronic dosing trials. There are
no well-documented adverse effects of American ginseng.
Steve Mathew
is a writer, who writes many great articles on herbal medicines
and ayurvedic medicines for common ailments and diseases. Visit
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