Hericium erinaceus

(from Medicinal Mushrooms - A Clinical Guide by Martin Powell, Pub. Mycology Press 2014)

Japanese Name - Yamabushitake

Chinese Name - Hou Tou Gu (Monkey Head Mushroom)

English Name - Lion’s Mane Mushroom/Hedgehog Mushroom

This delicious mushroom has been referred to as ‘Nature’s Nutrient for the Neurons’ on account of its ability to stimulate the production of nerve growth factor (NGF)1,2.

NGF plays an essential role in the differentiation and survival of several cell populations in the central and peripheral nervous system and lower than normal levels of NGF have been linked to early stages of both Alzheimer’s disease and dementia3-8.

Although therapeutic interest has largely focussed on its importance for neurological function, NGF plays a much wider role in maintaining homoeostasis in the body9,10. It is known to have insulinotropic, angiogenic, and antioxidant properties and reduced plasma levels of NGF have been associated with cardiovascular diseases and metabolic syndromes, including type 2 diabetes11,12.

It has been shown to accelerate wound healing and there is evidence that it could be useful in the treatment of skin and corneal ulcers13. Animal studies have shown NGF to have a profound effect on airway inflammation and asthma-related symptoms with increased NGF levels observed in bronchoalveolar lavage fluid and serum from patients with asthma14.

NGF also has a dynamic relationship with the immune system. Generation of NGF is increased after brain injury, in part due to cytokines produced by immune cells. At the same time immune cells express receptors for NGF, which is involved in immune modulation15.

Two families of compounds from H. erinaceus have been identified as being active in the stimulation of NGF production: the aromatic hericenones (isolated from the fruiting body) and the diterpenoid erinacines (isolated from the mycelium). Critically these molecules are small enough to pass through the blood-brain barrier. There is also evidence that they can increase myelination1,16-18.

In China the mycelium is used to make H. erinaceus pills to treat gastric and duodenal ulcers, chronic gastritis, gastric and oesophageal cancer.

DEMENTIA - In controlled studies H. erinaceus supplementation showed beneficial effects in patients with mild dementia. In one study six out of seven patients showed improvement in functional capacity (understanding, communication, memory etc.) while all seven showed improved Functional Independence Scores (eating, dressing, walking etc.), after consuming 5g H. erinaceus fruiting body daily in soup for six months1.

In another study, 30 patients aged 50-80 with mild dementia were randomised into treatment and control groups. H. erinaceus was given as tablets at 3g/day for 16 weeks and produced significant increases in cognitive function in the treatment group. However, four weeks after the conclusion of the trial, cognitive function scores decreased indicating a need for continued supplementation17.

MS - H. erinaceus fruiting body extract has been shown to improve the myelination process in mature myelinating fibres with possible benefits for MS patients18,19. NGF has also been shown to have a protective effect on axons and myelin by suppressing the immune-mediated inflammatory processes responsible for chronic brain destruction in neurodegenerative disorders such as MS by switching the immune response to an anti-inflammatory, suppressive mode in a brain-specific environment13.

NEUROPATHY - NGF plays a role in pain sensitivity and low NGF levels have been linked to sensory neuropathy in both in vivo and in vitro studies10. Enhanced NGF production has been shown to protect sensory function in diabetic rats and NGF reduction has been shown to cause cardiac sensory neuropathy21,22.

Clinical studies with recombinant human NGF indicate benefit in patients with diabetic polyneuropathy23 and NGF has also been reported to reduce pain in patients with HIV associated sensory neuropathy24,25. However, ability to promote regeneration of sensory neurons has yet to be demonstrated26,27.

NERVE DAMAGE - Rats given aqueous extract of H. erinaceus fruiting bodies showed faster recovery from nerve injury, suggesting potential for application of H. erinaceus in the early stages of nerve regeneration28-31.

ANXIETY / DEPRESSION - One study reports reduction in anxiety and depression from consumption of 2g/day (taken in cookies) and patients often report increased feelings of wellbeing when taking H. erinaceus, possibly due to the kappa opiod receptor agonist activity of the erinacines32,33.

MENOPAUSAL SYNDROME - Many patients report reduction in symptoms related to menopause and perimenopause, including sleep disturbance, anxiety and hot flushes (hot flashes) from consumption of H. erinaceus 3-5g/day d.w. although this is as yet unsupported by clinical research.

MRSA - Extracts of both fruiting body and mycelium exhibit anti-MRSA activity with erinacines identified as active compounds. In clinical tests in Japan MRSA is reported to have been cleared in a number of patients whose diet was supplemented with H. erinaceus34.

GASTRIC ULCERS - One of the traditional indications for H. erinaceus, it appears likely that the antibacterial action of the erinacines and hericenones contribute to its benefit in this regard, with Helicobacter pylori now known to be a major cause of gastric ulcers and chronic gastritis35-37.

A rat study on the effects of H. erinaceus aqueous extract on alcohol-induced ulcers showed a significant reduction of the ulcer area, as well as protection against gastric mucosa injury, while an in vitro study found that H. erinaceus extract was active against nine clinical strains of H. pylori with a 0.02% concentration having a 50% bactericidal activity38,39.

CLINICAL SUMMARY

Main Therapeutic Application - Dementia, Alzheimer’s disease, MS, nerve damage, menopausal synrome.

Key Component - Hericenones and erinacines.

Dose - Clinical trials support the use of dried fruiting body at a dose of 3-5g/day for increasing NGF production while animal studies on the use of H. erinaceus for gastric ulcers produced the best results with a daily intake of 500mg/kg, which equates to the dosage prescribed in the Chinese Phamacopoeia of 25-50g/day40.

It is likely that similar doses would be required in cases of MRSA.

High in vitro NGF promoting activity of mycelial extracts and the fermentation broth also indicates potential for the use of mycelial biomass products 41,42.

Caution - Asthma and other allergic conditions. Erinacine E is a potent agonist of the kappa opioid receptor with potential hallucinogenic properties33.

REFERENCES