The Unique Identity of Mushrooms and Their Potential Effects on Brain Health

Mushrooms are unique and edible fungi containing many bioactive compounds and antioxidants, such as ergothioneine, ergosterol, glutathione, and erinacines (specific to Hericium erinaceus species) that may promote neuroprotective effects, such as reducing neuroinflammation and reactive oxygen species in the brain. In addition to these neuroprotective compounds, the ergosterol in mushrooms can convert to vitamin D₂ after UV light exposure. Vitamin D has purported benefits for brain health as well, with vitamin D deficiency linked to increased risk of depression, anxiety, and cognitive decline. For centuries, mushrooms have been consumed for nutritive and medicinal purposes, however, science still does not know the full neuroprotective potential of mushrooms despite the many brain health-promoting compounds they contain. Research assessing the effects of mushrooms on brain health is limited and the results are mixed, with tentative improvements reported in mood and cognitive function. Research included in this thesis aims to assess the effects of consuming mushrooms produced to contain vitamin D on indexes of anxiety, depression, mood, cognition, and well-being. No prior studies, to our knowledge, have investigated the effects of fresh, whole vitamin D-enriched mushrooms on brain health-related outcomes in humans. The research presented in this thesis confirms that mushrooms are nutritionally unique foods that may not impact anxiety, depression, mood, cognitive function, or perceived well-being. In terms of influencing vitamin D status, mushrooms produced to contain vitamin D increase serum vitamin D₂ levels, but may decrease vitamin D₃ with no overall improvements in total vitamin D status. However, retrospective analyses revealed that the participants who consumed mushrooms with adequate amounts of vitamin D exhibited a better maintenance of total vitamin D compared to the control and those who did not have adequate vitamin D in their mushrooms. Continued research is needed to examine its effects on cognitive and mood outcomes in different populations.