First Controlled Human Trial Linking Maitake Mushroom Consumption to Improved Cognitive Function
- Gauri Khanna
- 9 hours ago
- 3 min read
A rigorous 18-week clinical trial found that daily consumption of maitake mushrooms significantly improved cognitive scores in healthy older adults, particularly in memory.
The study suggests that maitake mushrooms may help slow the transition from normal cognition to mild cognitive impairment, a precursor to dementia.
Immune activation, specifically natural killer cell activity, appears to play a meaningful role in the cognitive benefits observed.
Dementia now affects tens of millions of people worldwide, and with populations ageing rapidly, the search for accessible, dietary approaches to cognitive preservation has become pressing. Maitake mushrooms (Grifola frondosa), a species long prized in East Asian cuisine, have accumulated a promising body of evidence across immune function, blood pressure, and gut health. Until recently, however, their effects on cognition in healthy humans remained unexamined in a rigorous clinical setting.
A Fungus With a Long History and a New Purpose
Yukiguni Factory, a Japanese food and mushroom producer based in Niigata, has now helped change that. Researchers affiliated with the company, alongside academics from Kobe Pharmaceutical University and Shimane Rehabilitation College, conducted an 18-week randomised, double-blind, placebo-controlled trial involving 47 healthy Japanese adults aged 60 and older. The results, published in the Journal of Nutritional Science and Vitaminology in 2026, offer the first controlled human evidence linking maitake consumption to improved cognitive function in healthy older volunteers.
What the Trial Found
Participants were divided into three groups. Two consumed bread containing 50 grams of maitake mushroom paste, using either the Y10M or C5304 strain, both developed by Yukinugi Factory. A third group received identical bread without any mushroom content. To confirm compliance, researchers measured blood ergosterol, a lipid found almost exclusively in fungi, which rose significantly in both mushroom-consuming groups compared to the placebo group.
The primary cognitive outcome was measured using the Montreal Cognitive Assessment (MoCA), a tool well suited to detecting subtle early-stage decline that cruder tests, such as the widely used Mini-Mental State Examination, can miss. After 18 weeks, participants consuming the Y10M strain showed a statistically significant improvement in their overall MoCA scores compared to the placebo group. The memory subscale, considered one of the more demanding components of the assessment, also showed a significant positive shift in the Y10M group. The C5304 group, despite consuming a similar quantity of mushroom with comparable beta-glucan content, showed no such improvement, a finding the authors attribute to as-yet-uncharacterised differences in minor constituents or polysaccharide structures between the two strains.
No adverse events were recorded across any group, and blood biochemistry, liver function markers, and haematological parameters all remained within normal ranges throughout the trial.
The Immune Connection
Perhaps the most scientifically intriguing finding concerns the immune system. Natural killer (NK) cells, a type of immune cell that circulates in the bloodstream and plays a role in clearing abnormal proteins from tissues, were significantly more active in the Y10M group after 18 weeks. Crucially, this increased NK cell activity correlated positively with higher MoCA scores across all participants, suggesting the two phenomena are linked rather than coincidental.
This matters because growing research into fungal compounds has begun to illuminate how mushroom-derived polysaccharides, including beta-glucans, interact with the immune system in ways that extend well beyond their traditional associations. In the case of cognition, NK cells may help clear amyloid-beta, the protein whose accumulation is closely associated with Alzheimer's disease, by supporting microglial function, the brain's resident immune cells. The maitake polysaccharides in Y10M bread may stimulate this pathway, though the authors are careful to note that the precise mechanism remains unconfirmed.
This line of reasoning sits within a broader scientific conversation about how functional mushrooms are reshaping understanding of wellness across multiple biological systems.
Limitations and the Road Ahead
The trial's authors acknowledge a modest sample size, an unrestricted diet outside the intervention, and a focus limited to NK cells within a broader immune picture. Larger trials examining different populations, longer timeframes, and more granular mechanistic data will be needed before dietary guidance can be responsibly updated.
Nevertheless, the study provides a notable preliminary signal: a common edible mushroom, consumed daily at a practical dose, may contribute meaningfully to preserving cognitive health in older adults, with an immune-mediated mechanism that deserves considerably more scientific attention.