Supplementary file 1_Bridging soil health and human health: Mycobacterium vaccae as a keystone link.docx

Preclinical evidence, largely from rodent models, demonstrates its influence on serotonergic signaling, neuroinflammation, and stress-related behaviors; human evidence remains limited to a small number of early-phase and observational studies, which constrains causal inference and limits generalization of preclinical neurobehavioral findings to clinical practice. Preclinical and preliminary clinical findings support applications for allergic and inflammatory conditions and use as a vaccine or cancer-therapy adjuvant, with a more limited and preliminary evidence base for neuropsychiatric indications.

This review also discusses the ecological drivers of soil biodiversity loss and their possible relevance to public health, while highlighting gaps in safety data, independent replication, and methodological standardization that should be addressed.</p>