As the global population becomes increasing older, cognitive and motor changes that occur with aging are active areas of research. Foods with antioxidant and/or anti-inflammatory properties may protect the aging brain from an increase in oxidative stress and inflammation. In addition, reducing cardiovascular disease (See Section “Effects on Biomarkers of Cardiovascular Disease”) can be beneficial as these conditions can increase the risk of vascular and mixed dementias (Am J Clin Nutr 2010;92:115505). Although gaps remain in understanding the many issues related to neurological disorders, information about the increasing global public health importance of these conditions can be found at: http://www.who.int/mental_health/neurology/neurodiso/en/index.html and http://www.ninds.nih.gov/.
Although very preliminary, new data showing protective effects of mushrooms on betaamyloid peptide toxicity in the brain and mild cognitive impairment (both precursors to dementia) are very exciting and warrant further research on the ability of mushroom consumption to delay the onset of dementia / Alzheimer’s disease.
A double-blind, parallel-group, placebo-controlled trial has been performed on 50 to 80 year old Japanese men and women diagnosed with mild cognitive impairment in order to examine the efficacy of oral administration of Yamabushitake (Hericium erinaceus), an edible mushroom, for improving cognitive impairment, using a cognitive function scale. At weeks 8, 12 and 16 of the trial, the Yamabushitake group showed significantly increased scores on the cognitive function scale compared with the placebo group. The Yamabushitake group's scores increased with the duration of intake, but at week 4 after the termination of the 16 weeks intake, the scores decreased significantly. Laboratory tests showed no adverse effect of Yamabushitake. The results obtained in this study suggest that Yamabushitake may be effective in improving mild cognitive impairment (Mori et al., 2009). A series of benzyl alcohol derivatives (hericenones C to H), as well as a series of diterpenoid derivatives (erinacines A to I) have been isolated from the mushroom Hericium erinaceum. These compounds have been reported to significantly induce the synthesis of nerve growth factor (NGF) in vitro and in vivo. In a recent study, dilinoleoylphosphatidylethanolamine (DLPE) was isolated from the mushroom and was found to protect against neuronal cell death caused by beta-amyloid peptide (A beta) toxicity, endoplasmic reticulum (ER) stress and oxidative stress. Furthermore, the results of preliminary human trials showed that the mushroom was effective in patients with dementia in improving the Functional Independence Measure (FIM) score or retarding disease progression (Kawagishi and Zhuang, 2008).
Reactive oxygen species have been reported to be involved in the pathogenesis of a number of age-associated human health conditions. The mitochondrial respiratory chain is a direct intracellular source of reactive oxygen species. Ganoderma lucidum (50 and 250 mg/kg) has been shown to enhance the activities of mitochondrial dehydrogenases and complex I and II of the electron transport chain in the brain of aged male Wistar rats (Ajith et al., 2009). The level of lipid peroxidation was significantly lowered in the Ganoderma lucidum treated group compared to the aged controls. The activity exhibited by the extract of Ganoderma lucidum was partially correlated to its antioxidant activity. If Ganoderma lucidum is able to improve the function of mitochondria in the aged rat brain, then further studies would be warranted to evaluate possible future applications against ageing associated neurodegenerative diseases.