Are Bioplastics a Good Alternative to Traditional Plastics? A Recent Study in Mice Indicates They Might Not Be.
Featured image caption: Plastic pollution is a pervasive problem in our environment. Animals and humans are regularly exposed to small plastic particles called microplastics, which may pose health risks (Image source: “Micro-plastiques sur la plage de Famara aux Canaries,” by Emina Mamaca, CC BY 4.0, via Wikimedia Commons).
Source article: Liu, J., Xia, P., Qu, Y., Zhang, X., Shen, R., Yang, P., Tan, H., Chen, H., & Deng, Y. (2025). Long-term exposure to environmentally realistic doses of starch-based microplastics suggests widespread health effects. Journal of Agricultural and Food Chemistry, 73(16), 9867-9878. https://doi.org/10.1021/acs.jafc.4c10855
The microplastic problem
Plastic pollution is a growing global issue. Plastics persist in the environment and can take hundreds of years, or even longer, to decompose.1 When plastics break down, they release small plastic particles called microplastics, ranging in size from 1 nm to 5 mm. These particles can be smaller than a human red blood cell or as large as a pencil eraser. Microplastics in the environment enter the bodies of wildlife and humans, predominantly through contaminated food and drink, and can contribute to health issues such as inflammation, reduced fertility, and metabolic disorders, including type 2 diabetes.2
One idea for reducing plastic pollution is to use bioplastics, which are plastics made from renewable bio-based materials like plant starch and/or plastics that can biodegrade under the proper conditions.3 However, like traditional plastics, bioplastics form biomicroplastics (BioMPs) when they break down. It is largely unknown whether these BioMPs pose health risks similar to those of traditional microplastics. Researchers are now studying BioMPs to see if they, like traditional microplastics, can have adverse health effects in animals and humans.
Investigating the health effects of biomicroplastics
In a recent study published in the Journal of Agricultural and Food Chemistry, researchers tested whether long-term exposure to BioMPs affects health by feeding female lab mice diets containing varying levels of these particles. They hypothesized that BioMPs would disrupt insulin metabolic pathways and potentially have other widespread adverse effects on the body.
Researchers assigned mice to one of three treatment conditions. The first group received no BioMPs mixed in their food, the second group received a low concentration of BioMPs (~16 microplastic particles per day), and the third group received a high concentration of BioMPs (~82 particles per day). To ensure the study was as relevant to humans as possible, the particle size was based on microplastics previously recovered from human samples, and the concentration of particles was based on estimates of the daily dietary intake of microplastics in humans (scaled to mice). The BioMPs used in the study were composed of polylactic acid and starch. This is a common material used in food packaging, meaning humans could be exposed to these BioMPs through their diet.
After the mice were on their assigned diet for three months, the researchers compared several outcomes between the three groups. Samples of liver, colon, ovaries, feces, and blood were collected from each mouse. Tissues (liver, colon, ovaries) were cut into thin sections, stained, and viewed under a microscope to quantify markers of inflammation and structural damage. The researchers also quantified gene expression in liver tissue to determine whether exposure to BioMPs affected genes involved in insulin regulation. Fecal samples were used to assess changes in the gut microbiome, and blood was analyzed to quantify blood glucose levels (i.e., blood sugar), cholesterol, and other health indicators.
Biomicroplastics contribute to insulin resistance and inflammation in mice
The researchers detected signs of damage and inflammation in the tissue samples from mice exposed to BioMPs, particularly in the high-concentration group. They suggest that this damage could occur when particularly small BioMPs pass from the digestive tract into circulation. Once in circulation, these small particles can infiltrate organs and cause widespread damage. Because BioMPs, like those in this study, are often composed of bio-based materials, the body may be able to break them down further after ingestion, increasing the number of small particles that can infiltrate tissues and cause damage.
The study also found several lines of evidence supporting their hypothesis that BioMPs can disrupt insulin regulation. They found that mice that consumed more BioMPs tended to exhibit increased blood sugar levels and showed imbalances in their gut microbiomes. Specifically, the researchers noted changes in the abundance of bacteria associated with starch metabolism and insulin resistance. BioMP consumption also affected the expression of genes involved in insulin signaling.
Overall, these results suggest that long-term dietary exposure to BioMPs has widespread effects on the body, causing damage to several organ systems and increasing the risk of high blood sugar, insulin resistance, and potentially type 2 diabetes. Although this study was conducted in mice, the results indicate that the potential impacts of BioMPs on human health should be examined.
Reducing your exposure to microplastics
Research on microplastics and their impact on human health is ongoing. However, it may be beneficial to limit your contact with microplastics by minimizing your use of bioplastics and traditional plastics.
Since most microplastic exposure occurs through ingestion,2 a good way to reduce your exposure is to be mindful of what comes into contact with your food and drink. Try using glass or metal containers instead of plastic wrap and plastic storage containers for your leftovers. Additionally, avoid single-use plastics, such as water bottles, utensils, and straws, when possible. Plastic is everywhere, so it can’t be avoided entirely, but small steps like these can help you reduce your risk of ingesting microplastics.
Secondary sources:
- Environmental Protection Agency. (2025, May 15). Impacts of Plastic Pollution. EPA. https://www.epa.gov/plastics/impacts-plastic-pollution
- Wang, Z., Li, N., Ding, Y., Li, N., Su, M., Zhang, C., Li, Y., Wang, Q., Sha, C., Xia, B., Cheng, J., & Jiang, G. (2025). Microplastics and human health: Exposure pathways, toxicity mechanisms, and future research challenges. Journal of Environmental Chemical Engineering, 118807. https://doi.org/10.1016/j.jece.2025.118807
- Lackner, M., Mukherjee, A., & Koller, M. (2023). What are “bioplastics”? Defining renewability, biosynthesis, biodegradability, and biocompatibility. Polymers, 15(24), 4695. https://doi.org/10.3390/polym15244695
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