UCLA

Chewing gums typically contain plant-based or synthetic plastic polymers to improve their texture and flavor retention. These polymer fragments or microplastics can be released into the environment when disposed of improperly or ingested while chewing gums. Yet, how many microplastics a person may ingest while chewing gums is unknown. Analyzing microplastics released into saliva from a total of 10 natural and synthetic chewing gums, with n = 5 in each case, we found that each gram of chewing gum could release up to 637 microplastics per gram of chewing gum, and 94% of microplastics were released within the first 8 minutes of chewing. Surprisingly, synthetic chewing gum released a similar (p > 0.8) number of microplastics as natural or plant-based chewing gums, with a proportion of 92% of natural gum to synthetic gum. Microplastics released from chewing gums were predominantly small, with a median size of 45.4 µm. The four plastic polymers, polyolefins, polyterephthalates (PET), polyacrylamides, and polystyrenes, were predominantly found in saliva released during chewing gum use, among which polyolefins were the most abundant. The result reveals chewing gum consumption, irrespective of the type of chewing gums, would result in direct ingestion of microplastics and may have unintended health risks.