Linking biodiversity to human health through epigenetics: a literature review and pathway analysis  

Background: Climate change and anthropogenic land use contribute to global biodiversity loss, yet growing evidence suggests that biodiversity exposure positively influences human health. However, the biological mechanisms underlying this relationship remain poorly understood. Epigenetic modifications, which respond to environmental exposures and influence health outcomes, represent a promising pathway to explain how biodiversity may affect health. This study investigates the biodiversity–epigenetic–health nexus by: (1) conducting a scoping review to identify associations between exposure to biodiversity or vegetation and epigenetic variation; and (2) analysing reported epigenetic markers and biological pathways to explore their health implications. Methods: A scoping review was conducted in accordance with PRISMA guidelines across four databases: Embase, Web of Science, MEDLINE (Ovid), and Google Scholar. Eligible studies included primary human research published between 2000 and 2025, examining biodiversity or greenness exposures alongside epigenetic markers, including DNA methylation profiles and epigenetic clocks. Extracted data were synthesized to develop a framework describing associations of the selected studies and identifying overlapping genes between them. Additionally, pathway enrichment analyses were performed using genes annotated to identified CpG sites. Results: Sixteen studies met the inclusion criteria. Of these, fourteen reported at least one association between a biodiversity indicator and an epigenetic marker, although health implications were not always explicitly stated. Notably, greenness exposure was consistently correlated with reduced epigenetic age acceleration based on epigenetic clock analyses, suggesting a protective effect. Although no CpG site was shared across studies, 19 genes annotated to these CpG sites were identified in at least two studies. These genes have been associated with ageing, multiple cancer types, metabolic disorders including obesity and type 2 diabetes, and neurodegenerative and psychiatric conditions, including Alzheimer’s disease, cognitive decline, and schizophrenia. Pathway enrichment analysis revealed significant associations with eating disorders and bulimia, as well as asthma onset, allergic diseases, intraocular pressure, and haematological factors. Conclusions: This review demonstrates a potential link between biodiversity exposure and human health outcomes mediated by epigenetic mechanisms, although this field remains largely underexplored. The consistent inverse association with epigenetic age acceleration highlights the utility of epigenetic clocks as biomarkers in future biodiversity-health research. Further research is needed to elucidate causal mechanisms and to establish how biodiversity exposures influence health outcomes through epigenetic modifications.