Gut bacteria changes linked to liver problems from microplastic exposure

Jim Crocker
25th November, 2025

Gut bacteria changes linked to liver problems from microplastic exposure

Nine weeks of oral polystyrene microplastic (PS-MP) administration disrupted hepatic metabolism in leptin-deficient mice (Lep KO), evidenced by microplastic accumulation in the liver and alterations in liver histopathology compared to wild-type mice.

Image adapted from: Choi et al. / CC BY (Source)

Key Findings

  • This study, conducted on mice, found that microplastic exposure altered liver metabolism, impacting fat, sugar, and protein processing
  • Microplastics changed the types of bacteria present in the mice’s gut, reducing the overall diversity of bacterial species
  • In obese mice, microplastics increased the evenness of gut bacteria, potentially indicating an imbalance with certain species becoming dominant
The human body hosts trillions of microorganisms – bacteria, fungi, viruses – collectively known as the microbiota. These microbial communities reside in various locations, including the gut, mouth, and skin, and play a crucial role in maintaining health[2]. Disruptions to this delicate balance, termed dysbiosis, have been linked to a wide range of diseases, from cardiovascular issues to immune disorders[2]. Recent research from Pusan National University & Sun Yat-Sen University[1] investigates a potentially new contributor to this dysbiosis: microplastics. Microplastics (MPs) are tiny plastic particles resulting from the breakdown of larger plastic items. They are ubiquitous in the environment, found in water, soil, and even the air. Consequently, humans are exposed to them through various routes, including ingestion. While the health effects of microplastic exposure are still being investigated, emerging evidence suggests they can disrupt biological processes. The study focused on mice with a genetic predisposition to obesity (Lep KO mice). These mice were fed a diet containing microplastics for nine weeks. Researchers observed that the microplastics led to changes in the mice’s liver metabolism, specifically affecting how the liver processes fats, glucose (sugar), and amino acids (building blocks of proteins). Importantly, these metabolic changes were accompanied by alterations in the composition of the bacteria present in the mice’s feces – indicating a shift in the gut microbiota. To understand these changes, the researchers analyzed the overall microbial profile in the feces of both the obese mice exposed to microplastics and a control group of healthy mice (WT mice). They identified 10 phyla (broad groupings of bacteria) and 106 genera (more specific classifications) within the fecal samples. The results showed that two bacterial phyla were significantly altered in the obese mice after microplastic exposure, and 12 specific genera experienced notable changes. The researchers also used two key measures to assess the health of the gut microbiota: the Chao1 index and the Shannon index. The Chao1 index estimates the richness – the number of different types of bacteria present. The study found that microplastic exposure reduced this richness in both the obese and healthy mice. The Shannon index, on the other hand, measures evenness – how evenly distributed the different types of bacteria are. In the obese mice, microplastic exposure increased evenness. These findings suggest a link between microplastic-induced metabolic disruption in the liver and changes in the gut microbiota. The reduction in bacterial richness indicates a less diverse gut environment, which is often associated with poorer health outcomes[2]. The increased evenness in the obese mice, while seemingly positive, could indicate a dominance of certain bacterial species over others, potentially leading to imbalances. This research builds upon the growing understanding of the intricate relationship between the microbiota and host health[3]. Previous studies have demonstrated that the gut microbiota can influence various aspects of physiology, including nutrient absorption and immune function[4]. The current study adds to this knowledge by identifying microplastics as a potential environmental factor that can disrupt this delicate balance, particularly in individuals already predisposed to metabolic disorders like obesity. The study highlights how microbiota dysbiosis can lead to dysregulation of bodily functions and diseases[2]. The research doesn’t definitively prove that microplastics cause these changes in humans, as it was conducted on mice. However, it raises significant concerns about the potential health consequences of widespread microplastic exposure and underscores the need for further investigation into the effects of these particles on the human gut microbiota and overall health.

EnvironmentHealthBiochem

References

Main Study

1) Dysbiosis of gut microbiota in C57BL/6-Lepem1hwl/Korl mice during microplastics-caused hepatic metabolism disruption

Published 20th November, 2025

https://doi.org/10.1371/journal.pone.0336627

Related Studies

2) Microbiota in health and diseases.

https://doi.org/10.1038/s41392-022-00974-4

3) The gut microbiome in health and in disease.

https://doi.org/10.1097/MOG.0000000000000139

4) Molecular analysis of commensal host-microbial relationships in the intestine.

Journal: Science (New York, N.Y.), Issue: Vol 291, Issue 5505, Feb 2001


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