Take-out containers as nano- and microplastics reservoirs: Diet-driven gut dysbiosis in university students

Microplastics and nanoplastics (MNPs) are presenting a significant challenge to global ecosystems and human health, however, human evidence on NPs-specific effects and their impacts on gut microbiota remains absent. This study investigated the exposure characteristics of MPs/NPs and their associations with gut microbiota dysbiosis in a high-risk population-university students. Fecal samples from 24 university students were analyzed via Raman spectroscopy and micro-FTIR for comprehensive MPs/NPs characterization. 16S rRNA gene sequencing revealed taxonomic shifts linked to MPs/NPs exposure. Questionnaires were used to assess potential exposure pathways to MPs in humans. Through integrated Raman spectroscopy, micro-FTIR, and 16S rRNA gene sequencing, we characterized MPs/NPs in fecal samples (n = 24) while correlating exposure levels with microbial shifts. Microplastics were universally detected in fecal samples across all study participants, with concentrations ranging from 170.86 to 269.33 particles/100g, predominantly polyethylene terephthalate (PET, 83.42 %) and fibers (85.95 %). NPs (< 0.1 μm) constituted only 0.14 %. Frequent consumers of plastic-packaged foods (≥ 3/day) exhibited significantly higher total MPs, PET, polyethylene (PE), and fibers versus infrequent users. The analysis found a moderate correlation between participants' drinking water intake and fecal Polyvinyl chloride (PVC) concentrations (r=0.434, P=0.034). Gut microbiota analysis revealed that despite no significant β-diversity shifts, the exposure-stratified analysis uncovered critical taxonomic alterations with potential metabolic implications. The high-concentration group enriched Megasphaera and Shewanella while depleting Romboutsia at the genus level (P<0.05). Similarly, NP-negative group individuals exhibited higher Proteobacteria and Desulfobacterota (P < 0.05), higher Desulfovibrio, [Eubacterium]_eligens_group, and Negativibacillus, yet lower butyrate-producing Butyricicoccus compared to NP-positive group (P < 0.05). This study provides the first human evidence of NPs-associated gut dysbiosis, linking varying MP concentrations and sizes to gut microbiota alterations; it highlights dietary plastic packaging as a key exposure source. This work bridges critical gaps between in vitro NPs toxicity and real-world human health impacts, advocating for stricter regulations on single-use plastic packaging in food delivery systems targeting youth populations.