The researchers' analysis revealed that the lion's share of the microplastics were released from the gum in the first two minutes of chewing—thanks to the mechanical action, rather than the enzymatic properties of saliva—reaching 94 percent within eight minutes.

Chewing gum as a potential source of microplastics has yet to be widely studied. They’re made from a rubbery base, sweetener, flavorings, and other ingredients. Natural gum products are made using a plant-based chemical compound, and other products use synthetic rubber bases from ones that are petroleum-based.