Health risk analysis of micro-and nanoplastic exposure via the microbiota-gut-brain axis

As global plastic pollution continues to intensify, micro- and nanoplastics have emerged as novel environmental pollutants threatening human health. These particles enter the human body through dietary ingestion, inhalation, and skin contact,accumulating within the gastrointestinal tract. Their disruption of the intestinal microbiota has become a recent research focus. Studies indicate that micro- and nanoplastics can interfere with the normal mechanisms of the microbiota-gut-brain axis via neural, immune, and endocrine pathways, thereby inducing or exacerbating diseases. This paper reviews the exposure pathways and intestinal accumulation characteristics of micro- and nanoplastics in humans, the composition of normal gut microbiota and their metabolic products, elucidates the functional pathways of the microbiota-gut-brain axis and the potential impacts of microplastics upon entering the human body, and summarises the current research status, limitations, and future prospects.