The culinary mushroom that has been extensively studied for its neurohealth properties is H. erinaceus(Lion's Mane mushroom). The polysaccharides in an aqueous extract of the Lion's mane mushroom could induce neuronal differentiation and promote neuronal survival.[ 10] The chemical profile of extracts of this mushroom has been actively studied and reported by Kawagishi and co-researchers. Extracts of H. erinaceus induced the expression of neurotrophic factors such as NGF in astrocytes.[ 11, 12]
In their studies, hericenones were isolated from the fruiting bodies of Lion's mane while erinacines were isolated from the mycelium of the mushroom. Endoplasmic reticulum stress - attenuating compounds and dilinoleoyl phosphatidylethanolamine, a phospholipid with linoleic acid, an unsaturated fatty acid, purified from extracts of dried fruiting bodies of H. erinaceus, reduce endoplasmic reticulum stress-induced cell death. This may reduce the risk of neurodegenerative disease-induced cell death.[ 13] Fujiwara et al.[ 14] investigated the neuroprotective effect of H. erinaceus on the ischemic brain damage in a middle cerebral artery occlusion model in mice. Hericium erinaceus (300 mg/kg, continuously fed for 14 days after surgery) significantly decreased the size of the cerebral infarcts one day after the occlusion. In another study, a double-blind trial was conducted with 50- to 80-year-old Japanese men and women diagnosed with mild cognitive impairment in order to examine the efficacy of oral administration of H. erinaceus, for improving cognitive impairment, using a cognitive function scale based on the revised Hasegawa Dementia Scale (HDS-R).[ 15] The subjects in the H. erinaceus group took four 250 mg tablets containing 96% of Yamabushitake dry powder three times a day for 16 weeks. Cognitive function scale scores increased with the duration of intake.
Laboratory tests showed no adverse effect of H. erinaceus. The study suggested that H. erinaceus is effective in improving mild cognitive impairment.[ 15] Extracts of H. erinaceus induced phosphorylation of c-Jun N-terminal kinase (JNK) and its downstream substrate c-Jun, and increased c-Fos expression, suggesting that H. erinaceus promotes nerve growth factor gene expression via JNK signaling.[ 16] Furthermore, the efficacy of H. erinaceus in vivo has been examined. Mice given feed regime containing 5% (w/w) H. erinaceus dry powder for seven days showed an increase in the level of NGF mRNA expression in the hippocampus.[ 16]
These studies are very encouraging, and the consumption of H. erinaceus-fresh or processed is acceptable. There are many preparations available off the counter. However, there should be guidelines and monitoring to ensure safety, efficacy, and other parameters to ensure that these preparations are functional as claimed. The best option will be consumption of fresh mushrooms. The processing has been reported to affect the neurite stimulatory activity of H. erinaceus.[ 17, 18] Cultivation techniques and conditions may affect the medicinal properties of mushrooms too. Though Hericium erinaceus is a temperate mushroom, it can be cultivated in Malaysia, a tropical country.
The studies done by many researchers as well as on-going studies show that selected mushrooms do have neurotrophic properties that can be beneficial to humans. Regular consumption may promote nerve and brain health. This is particularly useful during injury (as in an accidents) or as we age. Further, there is a need to study the potential mushrooms to elucidate their mechanisms of activities as well as clinical trials. This far, only H. erinaceus has been extensively studied. The identification of more varieties of mushroom with these unique properties may contribute to identifying novel chemical agents that can have preventative or therapeutic functions.
Withania somnifera (ashwagandha) is a prominent herb in Ayurveda. This study was conducted to examine the possible effects of ashwagandha root extract consumption on muscle mass and strength in healthy young men engaged in resistance training.
In this 8-week, randomized, prospective, double-blind, placebo-controlled clinical study, 57 young male subjects (18-50 years old) with little experience in resistance training were randomized into treatment (29 subjects) and placebo (28 subjects) groups. Subjects in the treatment group consumed 300 mg of ashwagandha root extract twice daily, while the control group consumed starch placebos. Following baseline measurements, both groups of subjects underwent resistance training for 8 weeks and measurements were repeated at the end of week 8. The primary efficacy measure was muscle strength. The secondary efficacy measures were muscle size, body composition, serum testosterone levels and muscle recovery. Muscle strength was evaluated using the 1-RM load for the bench press and leg extension exercises. Muscle recovery was evaluated by using serum creatine kinase level as a marker of muscle injury from the effects of exercise.