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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 (see Chinese
Herbal Medicine). 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 mainstream cancer treatment in humans. There is some suggestion that
it may enhance the effects of certain chemotherapy (cancer treatment)
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. Many Chinese medicine practitioners
say the use of astragalus as an ingredient of traditional herbal
mixtures can help build the flow of vital energy or life force, called
qi (or ch'i), in the body which is essential to good health, well
being, and treatment of a number of diseases.
What does it involve?
When dried, the root of the astragalus plant is used in teas,
tinctures, and capsules. It is also available as a root slice and 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
effects of the herbs.
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 the astragalus extract enhanced the cell-destroying ability
(cytotoxicity) of a conventional immunotherapy treatment
(interleukin-2) by improving the immune response. It also partly
restored immune function of cells in test tubes. Astragalus has also
been found to stimulate the production of interferons (a group of
substances produced by the body as part of the normal defense mechanism
against viral infections) and reduce the length of colds.
Animal and lab studies may show a certain therapy is promising, but
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 with 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. Side effects that
have been reported 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 anticoagulants (“blood thinners”). It may also affect blood
pressure in some, so those taking blood pressure medicines may want to
be monitored by their physicians. There have also been reports of lower
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.
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 ordered
from our toll-free number (1-800-ACS-2345).
References
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.
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, et al. Chinese medicinal
herbs inhibit growth of murine renal cell carcinoma. Cancer Biother.
1994;9:153-161.
Memorial Sloan-Kettering Cancer Center. Astralagus. Available
at:
http://www.mskcc.org/mskcc/html/11571.cfm?RecordID=392&tab=HC.
Accessed April 6, 2007.
MD Anderson Cancer Center. Astralagus. Available at:
http://www.mdanderson.org/departments/cimer/display.cfm?id=1513AA63-4EC5-42EE-96425F81F9D3FAD6&method=displayFull&pn=6EB86A59-EBD9-11D4-810100508B603A14.
Accessed April 6, 2007.
McCulloch M, See C, Shu XJ, et al. Astragalus-based Chinese
herbs and platinum-based chemotherapy for advanced non-small-cell lung
cancer: meta-analysis of randomized trials. Journal of Clinical
Oncology. 2006;24:419-430.
Miller AL. Botanical influences on cardiovascular disease. Altern
Med Rev. 1998;3:422-431.
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
of Systematic Reviews. (1):CD004540, 2005.
Zhao KS, Mancini C, Doria G. Enhancement of the immune
response in mice by Astragalus membranaceus extracts. Immunopharmacology.
1990;20(3):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.
Revised: 06/26/2007
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