Can swallowed microplastics worsen colon inflammation in mouse research?
In mice, yes. A 2026 study found an environmentally sourced microplastic mix changed colon immune signals and increased susceptibility to inflammation and tumorigenesis.
What is actually in it
Microplastics are tiny plastic fragments that can enter food and water. Common polymers include polypropylene, polyethylene terephthalate, polystyrene, and polyethylene.
The colon is part of the digestive tract, so swallowed particles can come into contact with colon tissue before they leave the body.
What the research says
A 2026 study in Environ Pollut fed mice a mixture of environmentally sourced microplastics. The mix used 45 to 100 um fragments of polypropylene, polyethylene terephthalate, polystyrene, and polyethylene.
The researchers added the mixture to mouse diets at 5, 50, and 500 ug/g to reproduce proportions found in human stool. After 30 days, the mice had dose-dependent colon transcriptome changes and dysregulated T-cell and cytokine signaling pathways.
In disease models, the mixture worsened DSS-induced colitis at the medium dose and worsened AOM/DSS-induced colorectal tumorigenesis at the high dose after 75 days.
This is mouse research. It does not prove that food packaging causes colon cancer in people. It does support reducing avoidable plastic food contact. Glass storage is a practical swap for leftovers.