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Other common
name(s): saw palmetto berry extract, shrub palmetto,
dwarf palm
Scientific/medical
name(s): Serenoa
repens
Description
Saw palmetto is a low-growing palm tree found in the West
Indies and in coastal regions of the southeastern United States. The
tree grows 6 to 10 feet in height and has a crown of large leaves. The
berries are used in herbal remedies.
Overview
Some clinical studies have found that saw palmetto relieves
some symptoms of benign prostatic hyperplasia (BPH), or enlarged
prostate, such as difficult and frequent urination. However, at this
time there are no available study results that show that saw palmetto
can prevent or treat prostate cancer.
How is it promoted for use?
Saw palmetto is promoted for relieving some of the symptoms of
BPH, which include difficult and frequent urination. Chemicals in saw
palmetto berries called sterols are said to interfere with the ability
of hormones such as testosterone to cause prostate cells to grow.
Saw palmetto is sometimes promoted by itself or with other
herbs as a treatment for prostate cancer. Saw palmetto is also promoted
as a treatment for prostatitis (inflamed prostate gland). Some
proponents claim it increases sex drive and fertility and that it can
be used to treat low thyroid function.
What does it involve?
Saw palmetto supplements are available as capsules, tablets,
extracts, and as a tea. There is no standard dosage. In some clinical
studies for the treatment of BPH, patients received 320 milligrams per
day as a single dose or divided into 2 doses. A recent study showed
wide variation in the contents of different brands of saw palmetto
supplements.
What is the history behind it?
Native Americans ate the berries of the saw palmetto believing
they served as a tonic that nourished the body, stimulated appetite,
and promoted weight gain. They also used the herb to treat problems of
the urinary tract and genital system, such as trouble urinating or
frequent nighttime urination.
Saw palmetto supplements are very popular in Europe,
especially in Germany, where doctors often prescribe them for patients
with BPH. Saw palmetto is approved by Commission E (Germany's
regulatory agency for herbs) for prostate complaints or irritable
bladder. Saw palmetto supplements have become popular in the United
States in recent years as well and are often marketed "for prostate
health."
What is the evidence?
Some research has found that saw palmetto extract may reduce
symptoms of BPH. A review published in 2002 looked at 21 clinical
studies on saw palmetto conducted over the last 30 years and involving
more than 3,000 patients. The report concluded that saw palmetto
provided mild to moderate improvement in urinary symptoms such as
frequent nighttime urination and problems with urine flow. The
improvements were similar to those seen in men who took the
prescription drug finasteride (Proscar) for BPH. Saw palmetto also
caused fewer and milder side effects than finasteride. Whether side
effects are long-lasting is unclear. However, a 2006 study of 225 men
that carefully evaluated symptoms, maximal urine flow rate, prostate
size, and quality of life for one year found that saw palmetto had no
effect on any of these outcomes. A recent review concluded that
although most studies have suggested improvement in BPH, the precise
clinical use of saw palmetto remains undefined. Saw palmetto is not
currently recommended in major U.S. or European urology society
guidelines for treatment of BPH.
It is important to note, however, that benign prostatic
hyperplasia is not cancer. Some laboratory studies in cell cultures and
animal studies have hinted that saw palmetto may affect prostate cancer
cells (and therefore have potential for prevention or treatment), but
others have found no effect. Available scientific studies do not
support claims that saw palmetto can prevent or treat prostate cancer
in humans. One epidemiologic study of more than 30,000 men, published
in 2006, concluded that saw palmetto had no detectable influence on
prostate cancer risk. Further research in this area is needed.
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.
Side effects from saw palmetto are not common but may include
headache, nausea, vomiting, upset stomach, dizziness, constipation or
diarrhea, trouble sleeping, and fatigue. Its long-term effects and
safety have not been studied.
Men who have symptoms that might be caused by BPH, such as
difficult, frequent, or urgent urination, should see a doctor as soon
as possible, rather than treating themselves with saw palmetto. These
symptoms can also result from prostate cancer or other serious
conditions, and self-treatment with saw palmetto could delay diagnosis
and treatment.
Saw palmetto does not seem to interfere with the measurement
of prostate-specific antigen or PSA, a protein made by prostate cells
that is used in testing for prostate cancer, although this has not been
studied extensively. Since saw palmetto affects testosterone metabolism
in the same way as finasteride (which does affect PSA levels), some
doctors recommend that men have a baseline PSA test and digital rectal
exam before starting treatment with saw palmetto, just to be safe.
Relying on the use of saw palmetto 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
Avins AL, Bent S. Saw palmetto and lower urinary tract
symptoms: what is the latest evidence? Curr Urol Rep.
2006;7:260-265.
Bent S, Kane C, Shinohara K, Neuhaus J, Hudes ES, Goldberg H,
Avins AL. Saw palmetto for benign prostatic hyperplasia. N Engl J Med.
2006;354:557-566.
Bonnar-Pizzorno RM, Littman AJ, Kestin M, White E. Saw
palmetto supplement use and prostate cancer risk. Nutr Cancer.
2006;55:21-27.
Feifer AH, Fleshner NE, Klotz L. Analytical accuracy and
reliability of commonly used nutritional supplements in prostate
disease. J Urol.
2002;168:150-154.
Gruenwald J. PDR
for Herbal Medicines. 3rd ed. Montvale, NJ: Thomson PDR;
2004.
Habib FK, Ross M, Ho CK, Lyons V, Chapman K. Serenoa repens
(Permixon) inhibits the 5alpha-reductase activity of human prostate
cancer cell lines without interfering with PSA expression. Int J Cancer.
2005;114:190-194.
Hill B, Kyprianou N. Effect of permixon on human prostate cell
growth: Lack of apoptotic action. Prostate.
2004;61:73-80.
Madersbacher S, Berger I, Ponholzer A, Marszalek M. Plant
extracts: sense or nonsense? Current
Opinion in Urology. 2008;18:16-20.
Saw palmetto. Memorial Sloan-Kettering Cancer Center Web site.
http://www.mskcc.org/mskcc/html/69364.cfm. Updated August 7, 2007.
Accessed June 6, 2008.
Saw palmetto (serenoa repens [bartram] small). Mayo Clinic Web
site.
http://www.mayoclinic.com/health/saw-palmetto/NS_patient-sawpalmetto.
Updated February 1, 2008. Accessed June 6, 2008.
Sinclair RD, Mallari RS, Tate B. Sensitization to saw palmetto
and minoxidil in separate topical extemporaneous treatments for
androgenetic alopecia. Australas
J Dermatol. 2002;43:311-312.
Wadsworth TL, Worstell TR, Greenberg NM, Roselli CE. Effects
of dietary saw palmetto on the prostate of transgenic adenocarcinoma of
the mouse prostate model (TRAMP). Prostate.
2007;67:661-673.
Wilt T, Ishani A, Mac Donald R. Serenoa repens for benign prostatic
hyperplasia. Cochrane Database Syst Rev. 2002;(3):CD001423.
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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