Hericium erinaceus (lion's mane mushroom) has medicinal properties such as antioxidant, antimicrobial, and anticancer effects. Recently, there has been growing interest in its potential to protect and regenerate nerves. These benefits are likely due to bioactive components like polysaccharides, phenolic acids, and terpenoids (especially hericenones and erinacines) found in the mushroom. Hericenones and erinacines can cross the blood-brain barrier, promote nerve growth factor production, and have anti-inflammatory and neuroprotective effects in animal studies. They also appear to enhance cognition and increase levels of brain-derived neurotrophic factor, which supports brain health. Some studies have found similar effects in humans, particularly in improving memory and cognitive function in both healthy young people and people with cognitive impairments.
One randomized, double-blind, placebo-controlled parallel-group comparative study to evaluate the improvement of cognitive functions by taking supplements containing the fruiting body of lion mane mushroom for 12 weeks. The study included 31 healthy people who were older than 50 years of age. The study participants were randomly divided into two groups: the lion mane mushroom group (n=16) taking four lion mane mushroom supplements (contained 3.2 g of the powdered fruiting body of lion mane mushroom) in a day, or the placebo group (n=15) taking four placebo supplements in a day that did not contain lion mane mushroom for 12 weeks (1).
The study included three tests: the Mini-Mental State Examination (MMSE), the Benton visual retention test, and the Standard verbal paired-associate learning test (S-PA). MMSE alone showed that oral intake of lion mane mushrooms significantly improved cognitive functions and prevented deterioration (1).
The Mini-Mental State Examination (MMSE) is a common test for diagnosing dementia, conducted orally. Both groups in the study showed improved scores over time, but the group that took the lion's mane mushroom had a significantly greater increase in scores compared to the placebo group. The lion mane mushroom group consistently had higher scores, especially in "orientation to time." The age-adjusted statistical analysis showed a significant difference between the groups, confirming that lion mane mushroom supplements improved cognitive function in people with normal MMSE scores (1).
The study results confirmed that intake of the lion’s mane mushroom supplements for 12 weeks was significantly effective for the improvement of cognitive functions, especially in MMSE. The authors speculated that various chemical compounds, including hericenones, in the mushroom, have multiple effects on the brain’s neural networks and improve cognitive functions (1).
A randomized, double-blind, placebo-controlled study investigated the acute (60 min post-dose) and chronic (28-day intervention) effects of 1.8 g lion’s mane mushroom in 41 healthy adults aged 18-45 years. Following a single dose of lion’s mane mushroom, participants performed quicker on the Stroop task (p = 0.005) at 60 minutes post-dose. A trend towards reduced subjective stress was observed following 28-day supplementation (p = 0.051) (2).
The Stroop task is a psychological test that measures a person's selective attention, processing speed, and inhibitory control. It is based on the Stroop effect, which is the delay in reaction time that occurs when there is a mismatch between the name of a color and the color it is printed in.
In the Stroop task, participants are shown color words, such as "red", that is either printed in the same color as the word (congruent) or a different color (incongruent). For example, the word "red" might be printed in blue ink. The task is to name the color of the ink, ignoring the word itself. This creates a cognitive conflict because the brain automatically tries to read the word, which interferes with naming the ink color. As a result, it takes longer and is more likely to be incorrect to name the color when it does not match the ink color.
The interference score, which measures the increase in reaction time between congruent and incongruent words, is often used as a test parameter. The Stroop task can also be used with other tests to evaluate a person's overall executive processing abilities.
The findings suggested that lion’s mane mushrooms may improve speed of performance and reduce subjective stress in healthy young adults (2).
One study evaluated the effectiveness and safety of taking three lion’s mane mushroom capsules (350 mg each, containing 5 mg/g erinacine A) daily for treating patients with mild Alzheimer's Disease (3).
The study included a 3-week screening period without medication, followed by a 49-week double-blind treatment period. Patients were randomly assigned to either take three lion’s mane mushroom capsules daily or identical placebo capsules. Throughout the study, cognitive tests, eye exams, biomarker analysis, and brain imaging were conducted (3).
After 49 weeks, the placebo group showed a significant decline in cognitive function, while the lion’s mane mushroom group showed significant improvement in cognitive tests. The lion’s mane mushroom group also had better contrast sensitivity compared to the placebo group. Biomarkers related to brain health deteriorated in the placebo group but remained stable or improved in the lion’s mane mushroom group. Brain imaging showed that the placebo group experienced changes in brain regions related to cognitive decline, while the lion’s mane mushroom group did not show such changes. Except for four participants who dropped out due to mild side effects, such as abdominal discomfort, nausea, and skin rash, no other adverse effects were reported (3).
Taking three lion’s mane mushroom capsules daily for 49 weeks led to better cognitive function, daily living skills, and vision in patients with mild Alzheimer’s disease compared to the placebo group. The study suggests that the lion’s mane mushroom is safe, well-tolerated, and may offer neurocognitive benefits (3).
A double-blind, parallel-group, placebo-controlled trial was performed on 50- to 80-year-old Japanese men and women diagnosed with mild cognitive impairment to examine the efficacy of oral administration of lion’s mane mushroom for improving cognitive impairment, using a cognitive function scale based on the Revised Hasegawa Dementia Scale (HDS-R). After 2 weeks of preliminary examination, 30 subjects were randomized into two 15-person groups, one given lion’s mane mushroom and the other given a placebo. The subjects of the lion’s mane mushroom group took four 250 mg tablets containing 96% of lion’s mane mushroom dry powder three times a day (total 3 g per day) for 16 weeks. After the termination of the intake, the subjects were observed for the next 4 weeks (4).
At weeks 8, 12, and 16 of the trial, the lion’s mane mushroom group showed significantly increased scores on the cognitive function scale compared with the placebo group. The lion’s mane mushroom group's scores increased with the duration of intake, but at week 4 after the termination of the 16 weeks of intake, the scores decreased significantly (4).
A comparison of both group’s scores at week 16 with those at the start of intake revealed that 11 cases were judged ‘notably improved’ by a 3 and more point increase, 10 (71.4%) in the lion’s mane mushroom group and 1 (6.7%) in the placebo group, and 4 cases were judged ‘improved’ by a 2 point increase, 3 (21.4%) in the lion’s mane mushroom group and 1 (6.7%) in the placebo group. One case (7.1%) in the lion’s mane mushroom group and 13 cases (86.7%) in the placebo group were judged ‘unchanged’ by a score shift of 1, 0, or −1. Neither of the groups had a case judged as worsened by a 2 or more point decrease (4).
Laboratory tests showed no adverse effect of the lion’s mane mushroom. The results obtained in this study suggest that the lion’s mane mushroom is effective in reversibly improving mild cognitive impairment, and its continuous intake is necessary to maintain the effect (4).
These findings suggest the promising potential for lion's mane mushroom in supporting cognitive function and overall brain health. However, further research in larger sample sizes is needed to confirm and better understand these effects.
References:
1. Saitsu Y., Nishide A., Kikushima K., Shimizu K., Ohnuki K. Improvement of cognitive functions by oral intake of Hericium erinaceus. Biomed. Res. 2019;40:125–131. doi: 10.2220/biomedres.40.125.
2. Docherty S, Doughty FL, Smith EF. The Acute and Chronic Effects of Lion's Mane Mushroom Supplementation on Cognitive Function, Stress and Mood in Young Adults: A Double-Blind, Parallel Groups, Pilot Study. Nutrients. 2023 Nov 20;15(22):4842. doi: 10.3390/nu15224842. PMID: 38004235; PMCID: PMC10675414.
3. Li IC, Chang HH, Lin CH, Chen WP, Lu TH, Lee LY, Chen YW, Chen YP, Chen CC, Lin DP. Prevention of Early Alzheimer's Disease by Erinacine A-Enriched Hericium erinaceus Mycelia Pilot Double-Blind Placebo-Controlled Study. Front Aging Neurosci. 2020 Jun 3;12:155. doi: 10.3389/fnagi.2020.00155. PMID: 32581767; PMCID: PMC7283924.
4. Mori K, Inatomi S, Ouchi K, Azumi Y, Tuchida T. Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: a double-blind placebo-controlled clinical trial. Phytother Res. 2009 Mar;23(3):367-72. doi: 10.1002/ptr.2634. PMID: 18844328.
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