Ingested nano- and microsized polystyrene particles surpass the intestinal barrier and accumulate in the body.

Plastic pollution is a major global challenge of our times, baring a potential threat for the environment and the human health. The increasing abundance of nanoplastic (NP) and microplastic (MP) particles in the human diet might negatively affect human health since they - particularly in patients suffering from inflammatory bowel disease (IBD) - might surpass the intestinal barrier. To investigate whether ingested plastic particles cross the intestinal epithelium and promote bowel inflammation, mice were supplemented with NP or MP polystyrene (PS) particles for 24 or 12 weeks before inducing acute or chronic dextran sodium sulfate (DSS) colitis with continuous plastic administration. Although ingested PS particles accumulated in the small intestine and organs distant from the gastrointestinal tract, PS ingestion did not affect intestinal health nor did it promote colitis severity. Although the lack of colitis-promoting effects of small PS particles might be a relief for IBD patients, potential accumulative effects of ingested plastic particles on the gastrointestinal health cannot be excluded.