“Our initial hypothesis was that the synthetic gums would have a lot more microplastics because the base is a type of plastic,” Lisa Lowe, the study’s co-collaborator and a graduate student in Mohanty’s lab, explained in a statement. (Yes, certain types of synthetic gum contain petroleum-based polymers.)

Gum is made of plastic, and chewing both synthetic and natural gums could release microplastics into your mouth, according to a new study.

Are you keeping a mental list of all the sources of microplastics finding their way into your daily life? You may have another culprit to consider: It’s gum, according to a new pilot study that found chewing just one piece can release hundreds to thousands of microplastics into saliva.