Exploring the micro- and nanoplastics-diabetes nexus: Shattered barriers, toxic links, and methodological horizons.

Micro- and nanoplastics (MNPs) are emerging environmental contaminants with increasing evidence linking them to metabolic dysfunction, including diabetes-related outcomes. While experimental studies have demonstrated that MNPs disrupt glucose metabolism, insulin signaling, and lipid homeostasis through oxidative stress, systemic inflammation, and endocrine disruption, the implications for human health remain largely unexplored. Given the widespread presence of MNPs in food, water, and air, chronic low-dose exposure may contribute to metabolic disorders, yet epidemiological data are scarce. This review synthesizes current findings on MNP-induced metabolic disturbances, highlighting their impact on insulin resistance, hepatic fat accumulation, gut microbiota dysbiosis, and adipose tissue dysfunction. Additionally, we evaluate the analytical methodologies used to detect MNPs in biological systems and assess the relevance of exposure levels in real-world scenarios. By contextualizing these mechanisms within a broader public health framework, this review underscores the urgent need for large-scale human studies to establish causal links between MNP exposure and metabolic diseases. Addressing these knowledge gaps is critical for informing risk assessment, regulatory policies, and future research directions aimed at mitigating the metabolic risks associated with environmental plastic pollution.