Can the human body absorb microplastics (microscopic plastic particles)?

Microplastic Absorption in the Human Body

Yes, the human body can absorb microplastics, with evidence showing these particles can accumulate in various tissues after ingestion or inhalation, potentially causing immune responses and toxicity, though the full health implications remain under investigation. 1

Routes of Microplastic Entry into the Human Body

Microplastics (plastic particles less than 5mm in size) can enter the human body through multiple pathways:

• Ingestion: Through contaminated food and drinking water 2
• Inhalation: Via airborne microplastic particles 3
• Dermal contact: Through cosmetics and clothing 3

Evidence of Absorption and Accumulation

Recent research provides compelling evidence that microplastics not only enter but can be absorbed and accumulate in human tissues:

• Tissue distribution: A 2024 study detected microplastics (20-100 μm) in multiple human tissues, with the highest concentrations found in lung tissue (14.19 ± 14.57 particles/g), followed by small intestine, large intestine, and tonsil tissues 1
• Polymer types: Polyvinyl chloride (PVC) was identified as the dominant polymer type in human tissues, which is concerning due to its high polymer hazard index 1
• Gender differences: Significantly greater abundance of microplastics was found in females compared to males 1

Potential Biological Effects

Once absorbed, microplastics may cause several adverse effects:

• Particle toxicity: Microplastics can induce or enhance immune responses in the body 2, 4
• Chemical toxicity: Leaching of component monomers, additives, and adsorbed environmental pollutants from microplastics 2, 4
• Cellular damage: Studies confirm nano- and microplastics can induce apoptosis in cells and have genotoxic and cytotoxic effects 3
• Systemic distribution: Animal studies show that absorbed plastic particles can distribute to multiple organs including the liver, spleen, heart, lungs, thymus, reproductive organs, kidneys, and even cross the blood-brain barrier 5

Potential Health Implications

The health effects of microplastic accumulation may include:

• Respiratory disorders: Including lung cancer, asthma, and hypersensitivity pneumonitis 3
• Neurological symptoms: Such as fatigue and dizziness 3
• Gastrointestinal issues: Including inflammatory bowel disease and disturbances in gut microbiota 3
• Endocrine disruption: Additives and monomers in microplastics can interfere with the endocrine system 5
• Reproductive and developmental toxicity: Based on model animal and cell culture experiments 6

Knowledge Gaps and Research Limitations

Despite growing evidence, several important limitations exist in our current understanding:

• Limited human studies: Most evidence comes from animal models or cell cultures, with human studies being primarily correlational 6
• Exposure assessment: Robust evidence of human exposure levels is currently lacking 4
• Standardization issues: There is a lack of standardized methods for identifying microplastics in environmental and biological samples 2
• Particle characteristics: Significant differences exist between microplastics used in laboratory studies and those found in the environment 2

Clinical Implications

While definitive clinical guidelines do not yet exist for microplastic exposure, healthcare providers should:

• Be aware that chronic exposure is likely of greater concern than acute exposure due to the accumulative effect 4
• Recognize that effects are likely dose-dependent, though precise dose-response relationships are not yet established 2
• Consider microplastic exposure as a potential factor in patients with unexplained immune, respiratory, or gastrointestinal symptoms, particularly in those with high occupational exposure

Conclusion

Current evidence confirms that microplastics can be absorbed by the human body and accumulate in various tissues. While the full health implications remain under investigation, there is growing concern about potential immune, chemical, and microbial hazards associated with this exposure. Further research is urgently needed to establish exposure thresholds and definitive health outcomes.