When Plastic Comes Back to the Human Gut

Ni Putu Wulan Purnama Sari

Widya Mandala Surabaya Catholic University, Indonesia

29-05-2026

© Wix

Plastic was once celebrated as a miracle material. Cheap, durable, and versatile, it transformed modern life. Yet the same durability that made plastic useful has also created one of the largest environmental challenges in human history.

Global plastic production has exploded from less than 2 million metric tons in 1950 to 475 million metric tons in 2022. Without significant intervention, annual production could exceed 800 million metric tons by 2050. Today, an estimated 8 billion tons of plastic waste—about 80% of all plastic ever produced—has accumulated on the planet (OECD, 2022; Landrigan et al., 2025).

The story does not end when a plastic bottle is thrown away.

Over time, larger plastic items break down through sunlight, heat, mechanical stress, and biological processes (Lin et al., 2023). The result is the formation of microplastics—tiny particles smaller than 5 millimeters. These particles are now found almost everywhere: oceans, rivers, soils, the atmosphere, drinking water, salt, milk, and even plants (Xu et al., 2020; Zantis et al., 2021; Thompson et al., 2024).

In marine ecosystems, microplastics are often mistaken for plankton and consumed by small organisms. As these organisms are eaten by larger animals, the particles move through food webs. Studies have linked microplastic exposure to digestive damage, inflammation, impaired growth, and disruptions of microbial communities in aquatic species.

Eventually, the journey leads back to humans.

Scientists estimate that people may ingest between 0.1 and 5 grams of microplastics each week through food and water. While many particles pass through the digestive tract, some appear capable of interacting with the intestinal wall. More concerningly, microplastics have now been detected in human blood, placenta, breast milk, lungs, liver, kidneys, heart, and even brain tissue (Ragusa et al., 2021; Leslie et al., 2022; Thompson et al., 2024).

A recent review by Valerii and colleagues (2026) suggests that microplastics may disrupt gut homeostasis by reducing beneficial bacteria that produce health-promoting short-chain fatty acids while encouraging pro-inflammatory microbial populations. These changes could weaken the intestinal barrier and affect overall health.

Many scientific uncertainties remain. Researchers still do not fully understand how microplastics cross biological barriers, what exposure levels are most harmful, or how long-term exposure affects humans. Nevertheless, the evidence increasingly suggests that these particles are not merely environmental pollutants but biological stressors capable of interacting with living systems.

Plastic does not vanish once it leaves human sight. It fragments, circulates, and persists—moving through rivers, oceans, soils, food webs, and the atmosphere. Eventually, some of those particles find their way back into human bodies. Microplastics thus expose a simple but often overlooked truth: in nature, nothing is ever truly thrown away (Nguyen, 2026).

The presence of plastic particles in human tissues is not merely evidence of environmental contamination. It is a reminder that humanity remains embedded within the ecological systems it transforms. The microplastic crisis demonstrates the costs of overlooking these connections. The fate of human health is inseparable from the fate of the ecosystems that sustain it (Vuong, 2025; Khuc & Nguyen, 2026).

References

Khuc, V. Q., & Nguyen, M. H. (2026). Cultural Additivity Theory. Available at SSRN 6767760. https://ssrn.com/abstract=6767760 

Landrigan, P. J., et al. (2025). The Lancet Countdown on health and plastics. Lancet, 406, 1044-1062. https://doi.org/10.1016/S0140-6736(25)01447-3

Leslie, H. A., et al. (2022). Discovery and quantification of plastic particle pollution in human blood. Environment International, 163, 107199. https://doi.org/10.1016/j.envint.2022.107199

Lin, Y.-D., et al. (2023). Sources, degradation, ingestion and effects of microplastics on humans: a review. Toxics, 11, 747. https://doi.org/10.3390/toxics11090747

Nguyen, M.-H. (2026). Ayn Rand and Kingfisher on zero-carbon bombs and a sustainable future. Visions for Sustainability, 25(13474), 1-13. http://dx.doi.org/10.13135/2384-8677/13474  

OECD. (2022). Global plastics outlook: Economic drivers, environmental impacts and policy options. OECD Publishing.

Ragusa, A., et al. (2021). Plasticenta: first evidence of microplastics in human placenta. Environment International, 146, 106274. https://doi.org/10.1016/j.envint.2020.106274

Thompson, R. C., et al. (2024). Twenty years of microplastic pollution research—what have we learned? Science, 386, 6720. https://doi.org/10.1126/science.adl2746

Valerii, M. C., et al. (2026). Microplastics disrupt intestinal physiology: From microbiota composition to intestinal barrier integrity. Environmental Pollution, 403, 128418. https://doi.org/10.1016/j.envpol.2026.128418

Vuong, Q. H. (2025). Wild Wise Weird. AISDL. https://books.google.com/books?id=C5dDEQAAQBAJ

Xu, S., et al. (2020). Microplastics in aquatic environments: occurrence, accumulation, and biological effects. Science of The Total Environment, 703, 134699. https://doi.org/10.1016/j.scitotenv.2019.134699

Zantis, L. J., et al. (2021). Marine mammals and microplastics: a systematic review and call for standardization. Environmental Pollution, 269, 116142. https://doi.org/10.1016/j.envpol.2020.116142