Chewing Gum May Release Up to 3,000 Plastic Fragments Into Saliva

Under its minty scent and its apparent innocence, a chewing gum could release hundreds, even thousands of plastic fragments into saliva. How do these particles detach from it, and should we now view this everyday little pleasure differently?

A rapid release of microplastics within the first minutes of chewing

The experiment appears almost routine. Volunteers chew different gums while their saliva is collected at regular intervals. Yet, under the microscope, an unexpected scene emerges: microscopic fragments detach from the gum and pass directly into the mouth, ready to be swallowed with the saliva.

The UCLA team measured about 100 microplastics per gram on average, with values sometimes exceeding 600. Since a piece can weigh several grams, some gums could release nearly 3,000 particles. A striking result for a product chewed mindlessly on the subway or after lunch.

Mechanical abrasion of the teeth as the main driver of chewing-gum fragmentation

The phenomenon does not resemble a slow chemical dissolution. It is mainly driven by the mechanical work of the teeth. With every bite, stretch, and rub, the gum undergoes repeated abrasion. Tiny elements of its structure come loose, much like grains torn from a school eraser.

The release is particularly swift. According to measurements, 94 % of detected particles appear during the first eight minutes, with a peak at the start of chewing. Frequently changing gums could thus multiply exposures more than keeping the same piece for a long time.

That timeline also echoes the famous burst of freshness in the early minutes. Flavor and microplastics do not necessarily arise from the same mechanism, but they appear at the same moment. A rather troubling coincidence that makes that first bite suddenly less harmless.

Similar levels of microplastics in natural and synthetic gums

Researchers expected to find more plastic in synthetic gums, made with industrial polymers. Yet products marketed as natural released comparable amounts. The plant-based label is thus not, on its own, a guarantee of chewing free of plastic particles.

The analyses notably detected polyolefins, polyacryl amides, polystyrene, and compounds related to PET. In natural gums, their origin remains debated. They could come from certain manufacturing steps, industrial equipment, or packaging, rather than plant resins used as a base.

These figures do not mean that chewing gum automatically causes disease. The precise health effects of ingested microplastics remain poorly understood. The study mainly demonstrates a new route of exposure—direct and easily measurable—without proving any clinical consequence for consumers.

A study still limited but revealing the health and environmental implications

The work also has its limits. The instruments used did not detect particles smaller than about 20 micrometers. Potential nanoplastics even smaller could have escaped counting. Conversely, a pilot study with a small number of participants does not allow for perfect extrapolation to all brands and chewing habits.

Since its presentation at the American Chemical Society conference in March 2025, the research has been published in the Journal of Hazardous Materials Letters. It thus turns a preliminary alert into documented scientific findings, while leaving open the essential question: what do these particles actually become once swallowed?

One final issue remains after chewing. The fraction released into saliva represents only a small portion of the plastic contained in the gum. The rest often ends up on a sidewalk, under a table, or in the environment. This tiny sugary waste could thus continue to have an environmental life beyond the moment its flavor has faded.