Can swallowed microplastics affect thyroid function in animal research?
Animal research raises concern. A 2026 mouse study found swallowed micro- and nanoplastics changed thyroid tissue, hormone function, and inflammation signals.
What is actually in it
Microplastics and nanoplastics are tiny plastic particles. People can swallow them from food, dust, and water. Plastic food containers can also add to avoidable food contact with plastic.
The thyroid is a small gland in the neck. It helps control energy, body temperature, heart rate, and growth.
What the research says
A 2026 study in Ann Med gave 4-week-old male mice microplastics or nanoplastics by stomach tube at 30 mg/kg for 4 and 8 weeks.
The study found changed thyroid structure, altered endocrine function, more cell death signals, and higher inflammatory markers. Nanoplastics had a stronger effect than microplastics. The researchers linked the damage to NLRP3, CASPASE1, GSDMD, and NF-kB inflammation signaling.
This is animal evidence at a lab dose. It does not prove that everyday food or water exposure causes thyroid disease in people. Still, it supports a practical step: reduce plastic food contact where you can, especially with hot food. Glass storage is a better choice for leftovers.