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© Steven Foster
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Botanical name: Lentinus edodes
Parts used and where grown
Wild shiitake mushrooms are native to Japan, China, and other Asian countries and typically
grow on fallen broadleaf trees. Shiitake is now widely cultivated throughout the world,
including the United States. The fruiting body is used medicinally.
Shiitake has been used in
connection with the following conditions (refer to the individual
health concern for complete information):
Historical or traditional use (may
or may not be supported by scientific studies)
(may or may not be supported by scientific studies): Shiitake has been revered in Japan and
China as both a food and medicinal herb for thousands of years. Wu Ri, a physician from the
Chinese Ming Dynasty era (A.D. 1368–1644), wrote extensively about this mushroom, noting
its ability to increase energy, cure colds, and
eliminate worms.1
Active constituents
Shiitake contains proteins, fats, carbohydrates, soluble
fiber, vitamins, and minerals. In addition, shiitake’s key ingredient—found in
the fruiting body—is a polysaccharide called lentinan. Commercial preparations employ
the powdered mycelium of the mushroom before the cap and stem grow. This preparation is called
lentinus edodes mycelium extract (LEM). LEM is rich in polysaccharides and lignans.
One preliminary trial suggested that oral shiitake may be useful for people with hepatitis B.2 A highly purified, intravenous form of
lentinan is used in Japan and has been reported to increase survival in people with recurrent
stomach cancer, particularly when used in combination
with chemotherapy.3 Similar findings have
been found in one small clinical trial with people suffering from pancreatic
cancer.4 Case reports from Japan suggest that intravenous lentinan may be helpful
in treating people with HIV infection.5
However, large-scale clinical trials to confirm this action have not yet been performed.
Oral supplementation of lentinan from shiitake has been shown to significantly reduce the
recurrence rate of genital warts (condyloma acuminata). A preliminary trial involving a group
of men and women with genital warts found that those who took 12.5 mg of lentinan twice a day
for two months after laser surgery had significantly fewer recurrences (10.53% recurrence
rate) compared to those who only had the laser surgery (47.06% recurrence
rate).6
How much is usually taken?
The traditional intake of the whole, dried shiitake mushroom is 6–16 grams per
day.7 The mushroom is typically eaten in soups or taken as a decoction (i.e.,
boiled for 10–20 minutes, cooled, strained, and drunk). Recommended intake of LEM is
1–3 grams two to three times per day. Purified lentinan is considered a drug in Japan
and is not currently available as an herbal supplement in North America.
Are there any side effects or interactions?
Shiitake has an excellent record of safety but has been known to induce temporary diarrhea and abdominal bloating when used in high amounts (above
15–20 grams per day). Its safety during pregnancy
and breast feeding has not yet been established.
Are there any drug
interactions?
Certain medicines may interact with shiitake. Refer to
drug interactions for a list of those medicines.
References
1. Jones K. Shiitake: The Healing Mushroom. Rochester, VT:
Healing Arts Press, 1995.
2. Jones K. Shiitake: A major medicinal mushroom. Alt Compl Ther
1998;4:53–9 [review].
3. Taguchi I. Clinical efficacy of lentinan on patients with stomach
cancer: End point results of a four-year follow-up survey. Cancer Detect Prevent
Suppl 1987;1:333–49.
4. Matsuoka H, Seo Y, Wakasugi H, et al. Lentinan potentiates immunity
and prolongs survival time of some patients. Anticancer Res 1997;17:2751–6.
5. Hobbs C. Medicinal Mushrooms. Santa Cruz, CA: Botanica Press,
1995, 125–8.
6. Guangwen Y, Jianbin Y, Dongqin L, et al. Immunomodulatory and
therapeutic effects of lentinan in treating condyloma acuminata. CJIM
1999;5:190–2.
7. Hobbs C. Medicinal Mushrooms. Santa Cruz, CA: Botanica Press,
1995, 125–8.
Copyright © 2004 Healthnotes, Inc. All rights reserved.
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The information presented in Healthnotes is for informational
purposes only. It is based on scientific studies (human, animal, or in vitro),
clinical experience, or traditional usage as cited in each article. The results reported may
not necessarily occur in all individuals. For many of the conditions discussed, treatment with
prescription or over-the-counter medication is also available. Consult your doctor,
practitioner, and/or pharmacist for any health problem and before using any supplements or
before making any changes in prescribed medications. Information expires March 2005.
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Reliable and relatively consistent scientific data showing a substantial health benefit.
Contradictory, insufficient, or preliminary
studies suggesting a health benefit or minimal health benefit.
