Shiitake Health Benefits June 10 2014

Whether you know this mushroom as shitake or Lentinus edodes, Tricholomopsis edodes, Cortinellus edodes or Armillaria edodes, the result is the same - a fragrant mushroom that is tasty and well-known for its healing powers, as it has been since ancient times.

Numerous farmers are engaged in shiitake production in China today. In 2002, the total production of fresh shiitake topped two million tons. Japan produces more than a billion dollars' worth annually with some 200,000 people employed in the industry. The United States currently produces about five million pounds annually.

In Japan, there are two general types of shiitake. Donko is a round, thick-fleshed, partially opened cap, while koshin has thinner flesh and an open cap. The former is more highly prized for medicinal value, due in part to the retention of spores.

Medicinal Uses

One of the beneficial components of shitakes is lentinan. Lentinan is a beta-1, 3-D-glucan that activates the lymphokine activated killer and natural killer cells of the immune system to combat various cancers. It reduces prostaglandins responsible for creating inflammation that would prevent T-cell maturation.

It is medically approved in Japan for the treatment of gastric cancers. Lentinan is widely used in Japan for breast cancer in women who have had mastectomies without radiation follow-up. When chemotherapy is used, lentinan given prior to treatment prevents further immune system damage.

Lentinan was given to three patients with Mycobacterium tuberculinum resistant to drugs. When given by injection, the levels of opsonin toward the bacilli were so greatly elevated that excretion ceased in one patient, followed by great improvement. Resistance to both tuberculosis and Listeria monocytogenes was noted in this work.

A study looked at lentinan's effect on twenty-nine bacteria and ten pathogenic fungi. The extracts were 85 percent effective, including 50 percent effective against yeast and mold. A more recent study found intranasal administration of lentinan increased production of alveolar macrophages in the presence of Mycobacterium tuberulinum.

Polysaccharides in the mushroom help enhance production of interferon, which reduces blood vessel overgrowth in conditions such as macular degeneration of the eyes.

A polysaccharide, L-II, isolated from the fruiting body showed significant decrease in sarcoma 180, as well as phagocytosis of macrophage, increased TNF-alpha and IFN-gamma, increased NO production and catalase activity.

Eritadenine (lentinacin) helps lower total cholesterol, triglyceride, and phospholipids levels. In one human study, three hundred milligrams per day of eritadenine for seven days decreased bile cholesterol content in choled-ochostomy patients, while the total bile acid concentration, especially of deoxycholic acid, was increased.

A diet composed of 5 percent eritaden decreased blood pressure in hypertensive robably due to water-soluble oligosaccharii and content of tyrosinase.

Shiitake may be of benefit in treating colitis. Shuvy et al. (2008) looked at the mushroom's benefit in liver-mediated immune regulation. This mice study found oral ingestion of fruiting body extracts altered NRT lymphocyte distribution and increased intrahepatic CD8 (+)T lymphocyte trapping, leading to alleviation of immune-mediated colitis.

Fractions from shiitake, enoki, matsutake and hen of the woods have shown in lab studies the ability to inhibit conversion of stem cells into adipocytes, suggesting an anti-fat influence.

Eritadenine has been found active against the influenza virus in mice.

Macrophage activation by the high molecular weight glycoproteins from the mycelia was found to suppress liver cancer formation (Sug-ano et al. 1982). A freeze-dried extract of mycelia was given to an AIDS patient with HIV antibodies. After two months, the T4 cell count doubled and symptoms were alleviated.

Water-soluble extracts inhibit the herpes virus both in vitro and in vivo. Lignins known as EP3 and EPS4 inhibit herpes simplex virus types 1 and 2 and western equine encephalitis virus, and partially inhibit the effects of polio, measles, and mumps viruses.

Cell-free extracts from liquid fermentation of the mycelium inhibited the growth of Candida albicans, Streptococcus pyogenes, Staphylococcus aureus, and Bacillus megaterium (Hatvani 2001).

Even the mushroom juice inhibits pathogenic and opportunistic microorganisms. A study showed the juice of shiitake had pronounced effect on C. albicans, S. aureus, E. coli, and E.faecalis. Both lactobacteria and bifidobacteria, the healthy intestinal bacteria, were unaffected.

In fact, water extracts of L. edodes demonstrate growth-enhancing effects on both L. bre-vis and B. breve due to the disaccharide sugar, trehalose.

Other work suggests that the extracts can reduce the harmful effects of bacterial enzymes such as beta glucosidase, beta glucuronidase, and trytophanase, as well as reduce colon cancer formation.

Bthanol extracts of the mycelium possess antiprotozoal activity against Paramecium caudatum. An alcohol extract of the mycelium known as KS-2 has been found to induce the body's own production of interferon and stimulates macrophages to kill tumor cells.