Chewing Gums: Unintended sources of ingested microplastics in humans

Chewing gum is commonly used worldwide to freshen breath, promote oral health, and deliver medications. However, it contains plant-based or synthetic plastic polymers to enhance texture and flavor retention, making it a source of microplastics. These microplastics can be ingested through saliva produced while chewing gum. The exact amount of microplastics a person may ingest from gum has not been quantified. We aim to examine the release of microplastics from chewing gum during their consumption. 10 natural and synthetic gums were chewed by a human subject for a specific period (2 min to 20 min), and the saliva results during chewing were collected and analyzed for microplastics using an FTIR microscope and smartphone-enabled method to quantify microplastics. The results reveal that each gram of gum can release up to 637 microplastic particles, with 94% being released within the first 8 minutes of chewing. Interestingly, synthetic gums released a similar amount of microplastics as natural, plant-based gums (p > 0.8). Most of the released microplastics were small, with a median size of 45.4 µm, though smaller particles might have been missed due to the limitations of detection methods like FTIR. Four main plastic polymers were detected in the saliva, with polyolefins being the most common. These findings suggest that chewing gum may lead to the direct ingestion of microplastics, potentially posing health risks.