Can microplastics in drinking water change your gut bacteria?

What's actually in it

Microplastics are tiny fragments of plastic smaller than 5 millimeters. They come from water bottles, food packaging, and even tap water that has passed through plastic pipes. Every time you drink water or eat food that touched plastic, you swallow some of these particles.

Your gut is home to trillions of bacteria that help you digest food, fight infections, and regulate your mood. These bacteria are sensitive to what passes through your intestines, and microplastics are now a regular visitor.

What the research says

A 2026 study in Gut Microbes looked at how microplastic exposure affects the human gut microbiome. The researchers found that people with higher microplastic exposure had a different mix of gut bacteria compared to those with lower exposure.

Specifically, microplastics boosted bacteria linked to inflammation and metabolic problems while reducing bacteria that protect the gut lining. The shift wasn't subtle. The changes were large enough to measure even at the low levels of microplastics that most people encounter daily.

Your gut bacteria produce short-chain fatty acids that feed the cells lining your intestines. When microplastics push out the bacteria that make these protective compounds, your gut wall gets weaker. A weaker gut wall lets toxins and bacteria leak into your bloodstream, which can trigger inflammation throughout your body.