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Other common
name(s): milk vetch, huang qi, huang ch', radix
astragali, goat's horn, green dragon, locoweed
Scientific/medical
name(s): Astragalus membranaceus
Description
Astragalus is a traditional Chinese herbal medicine taken from
a plant known as Astragalus membranaceus, which is a type of bean or
legume. The root is used in herbal remedies.
Overview
Animal studies and preliminary human clinical studies suggest
that astragalus may improve functioning of the immune system and might
possibly enhance the effect of conventional immune therapy for some
cancers. However, available scientific evidence does not support claims
that astragalus can prevent cancer, cure cancer, or reduce side effects
of conventional cancer treatment in humans. There is some suggestion
that it may enhance the effects of certain chemotherapy drugs, but more
testing is needed.
How is it promoted for use?
The herb is promoted to kill cancer cells, reduce the toxic
effects of chemotherapy, help heal burns, protect against heart
disease, fight the common cold, and help improve overall weakness.
Proponents also claim astragalus can stimulate the spleen, liver,
lungs, circulatory, and urinary system, and help treat arthritis,
asthma, and nervous conditions. They further claim it can lower blood
sugar levels and blood pressure.
What does it involve?
When dried, the root of the astragalus plant is used in teas,
tinctures, and capsules. It is also available as dried slices of the
root and as a powder. In China, healers sometimes use the dried root in
soups or roast the root in honey for use as a medicinal tonic.
Astragalus is usually combined with other Chinese herbal remedies to
enhance the herbs' effects.
What is the history behind it?
For more than 2,000 years, Chinese herbalists have recommended
astragalus for helping the human body build up energy and resist
diverse diseases including cancer, heart disease, liver and kidney
problems, and infections. It is the most commonly used herb in Chinese
medicine. Conventional medical practitioners have recently become
interested in the possibility that astragalus might lessen the side
effects of chemotherapy.
What is the evidence?
The scientific evidence for the ability of astragalus to
enhance the immune system and fight diseases, including cancer and
heart disease, comes mostly from laboratory and animal studies.
Researchers at The University of Texas M.D. Anderson Cancer Center
found that astragalus extract enhanced the cell-destroying ability, or
cytotoxicity, of the conventional immunotherapy treatment interleukin-2
by improving the immune system's response. It also partly restored the
immune function of cells in test tubes. Astragalus has also been found
to reduce the length of colds and stimulate the production of
interferons, a group of substances produced by the body as part of the
normal defense mechanism against viral infections.
Though animal and laboratory studies show promise, more
studies are needed to find out whether the results apply to humans. A
few studies of humans have been done, mostly in China, and some suggest
that this herb might have some benefit for immune system cells in
people who have cancer. However, most experts who have reviewed these
studies said that flaws in the way the most of this research was
designed, conducted, or analyzed make it difficult to say whether their
results are valid. A 2006 review of the most reliable studies of
astragalus and lung cancer found some evidence that this herb might
enhance the effects of some chemotherapy drugs and recommended that
more rigorously designed studies be conducted.
The consensus of available scientific evidence does not
support claims that astragalus can prevent or cure cancer in humans or
decrease the toxic effects of chemotherapy or other conventional cancer
treatments. Large-scale human trials are needed to verify the benefits,
if any, of astragalus in people with cancer.
Are there any possible problems or
complications?
This product is sold as a
dietary supplement in the United States. Unlike drugs (which must be
tested before being allowed to be sold), the companies that make
supplements are not required to prove to the Food and Drug
Administration that their supplements are safe or effective, as long as
they don't claim the supplements can prevent, treat, or cure any
specific disease.
Some such products may not
contain the amount of the herb or substance that is written on the
label, and some may include other substances (contaminants). Actual
amounts per dose may vary between brands or even between different
batches of the same brand.
Most such
supplements have not been tested to find out if they interact with
medicines, foods, or other herbs and supplements. Even though some
reports of interactions and harmful effects may be published, full
studies of interactions and effects are not often available. Because of
these limitations, any information on ill effects and interactions
below should be considered incomplete.
Astragalus is generally considered safe. Reported side effects
include abdominal bloating, loose stools, low blood pressure, and
dehydration. People with autoimmune diseases (such as rheumatoid
arthritis or lupus) or people taking immune suppressing medicines (such
as corticosteroids or cyclosporin) should talk to their doctors before
taking this herb. There is some concern that astragalus might interfere
with blood clotting, so some doctors recommend it should not be taken
before surgery or in people taking aspirin-like drugs or blood-thinning
medicines. It may also affect blood pressure in some, so those taking
blood pressure medicines may need to be monitored by their physicians.
There have also been reports of lowered blood sugar, which could be
dangerous for those with diabetes or hypoglycemia.
Other potential interactions between herbs and medicines are
possible, some of which may be dangerous. Always tell your doctor and
pharmacist about the herbs you are taking.
Allergic reactions are rare. People who are allergic to other
legumes may be more likely to be allergic to astragalus. Relying on
this type of treatment alone and avoiding or delaying conventional
medical care for cancer may have serious health consequences.
Additional Resources
More information from your American Cancer
Society
The following information on complementary and alternative
therapies may also be helpful to you. These materials may be found on
our Web site (www.cancer.org)
or ordered from our toll-free number (1-800-ACS-2345).
References
Astralagus. Memorial Sloan-Kettering Cancer Center Web site.
http://www.mskcc.org/mskcc/html/69128.cfm. Updated September 20, 2007.
Accessed June 4, 2008.
Chu DT, Lepe-Zuniga J, Wong WL, LaPushin R, Mavligit GM.
Fractionated extract of Astragalus membranaceus, a Chinese medicinal
herb, potentiates LAK cell cytotoxicity generated by a low dose of
recombinant interleukin-2.
J Clin Lab Immunol. 1988;26:183-187.
Cui R, He J, Wang B, Zhang F, Chen G, Yin S, Shen H.
Suppressive effect of Astragalus membranaceus Bunge on chemical
hepatocarcinogenesis in rats. Cancer
Chemother Pharmacol. 2003;51:75-80. Epub 2002 Nov 26.
Khoo KS, Ang PT. Extract of Astragalus membranaceus and
ligustrum lucidum does not prevent cyclophosphamide-induced
myelosuppression. Singapore
Med J. 1995;36:387-390.
Lau BH, Ruckle HC, Botolazzo T, Lui PD. Chinese medicinal
herbs inhibit growth of murine renal cell carcinoma. Cancer Biother.
1994;9:153-161.
McCulloch M, See C, Shu XJ, Broffman M, Kramer A, Fan WY, Gao
J, Leib W, Shieh K, Colfrod JM Jr. Astragalus-based Chinese herbs and
platinum-based chemotherapy for advanced non-small-cell lung cancer:
meta-analysis of randomized trials. J Clin Oncol.
2006:24:419-430.
Miller AL. Botanical influences on cardiovascular disease. Altern Med Rev.
1998;3:422-431.
Natural Standard. Herbal/plant therapies: astragalus
(astragalus membranaceus). Complementary/Integrative Medicine Education
Resources, The University of Texas M.D. Anderson Cancer Center Web
site.
http://www.mdanderson.org/departments/cimer/display.cfm?id=1513AA63-4EC5-42EE-96425F81F9D3FAD6&method=displayFull.
Accessed June 4, 2008.
Rittenhouse JR, Lui PD, Lau BH. Chinese medicinal herbs
reverse macrophage suppression induced by urological tumors. J Urol.
1991;146:486-490.
Taixiang W, Munro AJ, Guanjian L. Chinese medical herbs for
chemotherapy side effects in colorectal cancer patients. Cochrane Database Syst Rev.
2005;(1):CD004540.
Zhao KS, Mancini C, Doria G. Enhancement of the immune
response in mice by Astragalus membranaceus extracts. Immunopharmacology.
1990;20:225-233.
Note: This information may not cover
all possible claims, uses, actions, precautions, side effects or
interactions. It is not intended as medical advice, and should not be
relied upon as a substitute for consultation with your doctor, who is
familiar with your medical situation.
Last Medical Review: 11/01/2008
Last Revised: 11/01/2008
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