Metabolic footprint of microplastics and nanoplastics: From environmental exposure to metabolic diseases

Microplastics and Nanoplastics (MPs/NPs), as emerging environmental pollutants, are characterized by their resistance to degradation, high mobility, and strong adsorption capacity. They are widely distributed across global environments and enter the human body through multiple pathways, where they interfere with metabolic health. This review introduces the concept of "metabolic footprint" to systematically analyze the environmental behavior of MPs/NPs, human exposure routes, and the associations between MPs/NPs, metabolic pathways, and metabolic diseases. MPs/NPs can induce energy metabolism disorders, insulin resistance, and chronic inflammation through mechanisms including mitochondrial dysfunction, disruption of gut microbiota balance, and interference with hepatic lipid metabolism, thereby increasing the risk of metabolic diseases such as obesity, type 2 diabetes, metabolic dysfunction-associated fatty liver disease, and atherosclerosis. In addition, MPs/NPs of different particle sizes exert distinct pathological effects through size-dependent mechanisms. Furthermore, as carriers of environmental pollutants, MPs/NPs can produce synergistic toxicity. There is an urgent need to establish comprehensive monitoring systems for MPs/NPs, develop effective intervention strategies, and conduct in-depth studies on their long-term health impacts, thereby providing a scientific basis for the formulation of relevant public health policies.