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Other common
name(s): white birch, silver birch; compounds made from
the bark include butalin and betulinic acid, also called bet a
Scientific/medical
name(s): Betula
pendula, Betula alba
Description
White birch is a tree that grows in northern Europe and North
America. The bark, leaves, and buds from this and related birch trees
are used in herbal and folk medicines. One of the chemicals that has
been isolated from birch bark is called betulin. Betulinic acid, which
is made from betulin, is being studied as a possible cancer treatment.
Betulin has also been found in many other plants.
Overview
Birch bark, buds, and leaves are used in folk medicine but
have not been studied to find out whether they are safe or effective.
However, betulinic acid may hold promise as an anticancer agent. Some
laboratory and animal studies of betulinic acid have reported antitumor
activity. Additional studies are under way to find out whether it has a
role in treating several forms of cancer, including melanoma and
certain brain cancers. Clinical trials are needed to determine what
effect, if any, betulinic acid may have in treating cancer in humans.
How is it promoted for use?
Birch bark or white birch (which contains betulinic acid and
other compounds) is used on the skin to treat warts, eczema, and other
skin conditions. Promoters say that birch tea can be taken internally
as a diuretic or a mild sedative and that it can be used as a treatment
for rheumatism, gout, and kidney stones. The leaves are sometimes used
on the scalp to help with hair loss and dandruff. Birch tar (an oil
distilled from birch bark) is used on the skin for skin irritations and
parasites. Other claims for birch bark include the treatment of
diarrhea, dysentery, and cholera.
Some researchers believe that betulin, which can be extracted
from birch bark and other sources, causes some types of tumor cells to
start a process of self-destruction called apoptosis. They also believe
that betulinic acid slows the growth of several types of tumor cells
and the human immunodeficiency virus (HIV). Some researchers also think
it has antibacterial properties.
What does it involve?
Pure betulinic acid is not directly available for public use,
but birch bark flakes, powder, capsules, oil, sap, and liquid extracts
are sold in herbal medicine shops and on the Internet. Birch bark,
buds, or leaves are used internally or externally. Tea can be made by
steeping a teaspoon of the birch bark in a cup of boiling water for 15
minutes. Proponents recommend drinking from 2to 5 cups of tea per day.
Birch leaves or powder can also be used to make tea. For skin
conditions, birch leaf tea may be used as a wash or added to bath
water. Birch bark or leaves can be applied directly to the skin as
well. Birch oil is sometimes used in ointments or liniments and is
considered a substitute for wintergreen. Some people also drink small
amounts of fresh or bottled birch sap as a tonic.
What is the history behind it?
White birch bark has been used by Native Americans as a folk
remedy for some time. It was used in tea and other beverages to treat
stomach and intestinal problems such as diarrhea and dysentery. In
Russia, it has been used since 1834. In Europe, birch sap was fermented
into beer, wine, and other spirits. Its inner bark was sometimes eaten
as food.
In 1994, scientists at the University of North Carolina
reported that chemicals found in white birch bark slowed the growth of
HIV. The following year, a researcher at the University of Illinois
reported that betulinic acid killed melanoma cells in mice. Since then,
a number of researchers have conducted laboratory tests on betulinic
acid to determine its antitumor properties. Since that time, betulin
has been found in several other plant sources.
What is the evidence?
There has not been enough scientific study of white birch in
humans to draw conclusions about its usefulness in treating illness,
although some birch extracts have been studied for safety. Xylitol, a
type of sugar, can be made from birch and has been approved to flavor
food. Several other compounds extracted from birch have also been
approved by the U.S. Food and Drug Administration (FDA) for use as food
additives.
Betulinic acid has not been studied in humans, but several
laboratory studies have looked at its effects when it is added to
cancer cells growing in laboratory dishes. These studies, using the
pure chemical betulinic acid rather than birch bark, have been
published in peer-reviewed medical journals and suggest that betulinic
acid holds some promise for patients with melanoma, certain nervous
system tumors, and other forms of cancer. Three German studies
concluded that betulinic acid showed anti-tumor activity against cells
from certain types of nervous system cancers in children. Two
laboratory studies conducted at the University of Illinois indicated
that betulinic acid may prove useful as an antitumor drug.
Several studies have found that betulinic acid increases
sensitivity of cancer cells in laboratory dishes or in rodents to
chemotherapy drugs such as vincristine, 5-fluorouracil, irinotecan, and
oxaliplatin. Some researchers are testing synthetic chemicals related
to betulinic acid to determine which are the strongest in killing
cancer cells or preventing their growth. Studies are still going on to
find out whether these results can be applied to humans.
Results from a German nonrandomized clinical trial published
in 2006 indicated that birch bark extract may be an effective treatment
for actinic keratosis, a pre-cancerous skin condition. However, birch
bark extract cannot be recommended for actinic keratoses until further
studies have compared it with conventional treatments already known to
be safe and effective.
Are there any possible problems or
complications?
This product is sold as a
dietary supplement in the United States. Unlike companies that produce
drugs (which must provide the FDA with results of detailed testing
showing their product is safe and effective before the drug is approved
for sale), the companies that make supplements do not have to show
evidence of safety or health benefits to the FDA before selling their
products. Supplement products without any reliable scientific evidence
of health benefits may still be sold as long as the companies selling
them do not 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). Though the FDA has written new rules
to improve the quality of manufacturing processes for dietary
supplements and the accurate listing of supplement ingredients, these
rules do not take full effect until 2010. And, the new rules do not
address the safety of supplement ingredients or their effects on health
when proper manufacturing techniques are used.
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.
Birch products that are sold as supplements have not been
studied for safety. However, people who are sensitive to aspirin should
not use birch products, because birch contains large amounts of
aspirin-like compounds. Birch may also pose a hazard to people with
poor heart or kidney function. The full range of effects is not well
known. Pregnant women, breastfeeding women, and children should not use
birch products. Birch has been reported to cause skin rashes and, like
most plants, may cause allergic reactions.
Researchers are still studying betulinic acid. Further testing
is needed to find out whether it is safe for humans.
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
Beaulieu JE. Herbal therapy interactions with
immunosuppressive agents. US Pharmacist Web site.
http://www.uspharmacist.com/oldformat.asp?url=newlook/files/feat/herbals.htm.
Accessed June 9, 2008.
Betulaceae (birch family). Botanical Dermatology Data Base Web
site.
http://bodd.cf.ac.uk/BotDermFolder/BotDermB/BETU.html. Accessed June 9,
2008.
Center for Food Safety and Applied Nutrition. EAFUS: a food
additive database. US Food and Drug Administration Web site.
http://vm.cfsan.fda.gov/~dms/eafus.html. Accessed June 9, 2008.
Chintharlapalli S, Papineni S, Ramaiah SK, Safe S. Betulinic
acid inhibits prostate cancer growth through inhibition of specificity
protein transcription factors. Cancer
Res. 2007;67:2816-2823.
Eiznhamer DA, Xu ZQ. Betulinic acid: a promising anticancer
candidate. IDrugs.
2004;7:359-373.
Gruenwald J.
PDR for Herbal Medicines. 3rd ed. Montvale, NJ: Thomson
PDR; 2004.
Huyke C, Laszczyk M, Scheffler A, Ernst R, Schempp CM,
Treatment of actinic keratoses with birch bark extract: a pilot study
[in German]. J Dtsch
Dermatol Ges. 2006;4:132-136.
Jung GR, Kim KJ, Choi CH, Lee TB, Han SI, Han HK, Lim SC.
Effect of betulinic acid on anticancer drug-resistant colon cancer
cells. Basic Clin
Pharmacol Toxicol. 2007;101:277-285.
Kasperczyk H, La Ferla-Brühl K, Westhoff MA, Behrend
L, Zwacka RM, Debatin KM, Fulda S. Betulinic acid as new activator of
NF-kappaB: molecular mechanisms and implications for cancer therapy. Oncogene.
2005;24:6945-6956.
Kessler JH, Mullauer FB, de Roo GM, Medema JP. Broad in vitro
efficacy of plant-derived betulinic acid against cell lines derived
from the most prevalent human cancer types. Cancer Lett.
2007;251:132-145.
Liby K, Honda T, Williams CR, Risingsong R, Royce DB, Suh N,
Dinkova-Kostova AT, Stephenson KK, Talalay P, Sundararajan C, Gribble
GW, Sporn MB. Novel semisynthetic analogues of betulinic acid with
diverse cytoprotective, antiproliferative, and proapoptotic activities.
Mol Cancer Ther.
2007;6:2113-2119.
Pisha E, Chai H, Lee IS, Chagwedera TE, Farnsworth NR, Cordell
GA, Beecher CW, Fong HH, Kinghorn AD, Brown DM, et al. Discovery of
betulinic acid as a selective inhibitor of human melanoma that
functions by induction of apoptosis. Nat Med.
1995;1:1046-1051.
Sawada N, Kataoka K, Kondo K, Arimochi H, Fujino H, Takahashi
Y, Miyoshi T, Kuwahara T, Monden Y, Ohnishi Y. Betulinic acid augments
the inhibitory effects of vincristine on growth and lung metastasis of
B16F10 melanoma cells in mice. Br
J Cancer. 2004;90:1672-1678.
Schmidt ML, Kuzmanoff KL, Ling-Indeck L, Pezzuto JM. Betulinic
acid induces apoptosis in human neuroblastoma cell lines. Eur J Cancer.
1997;33:2007-2010.
Thurnher D, Turhani D, Pelzmann M, Wannemacher B, Knerer B,
Formanek M, Wacheck V, Selzer E. Betulinic acid: a new cytotoxic
compound against malignant head and neck cancer cells. Head Neck.
2003;25:732-740.
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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