Can microplastics from breast milk disrupt your baby's gut bacteria and immune system?

What's actually in it

Breast milk is the ideal food for babies, but it can contain microplastics that a mother absorbs from food, water, and air. These tiny plastic particles pass into breast milk and are swallowed by the nursing infant. Breast milk also carries beneficial bacteria that seed the baby's gut, a process called vertical transmission.

What the research says

A 2026 study in FASEB J found that polystyrene microplastics in breast milk disrupted the normal transfer of gut bacteria from mother to baby. The microplastics interfered with how beneficial bacteria colonize the infant's gut, a process that's critical for building a healthy immune system.

Babies who don't get the right gut bacteria in early life may face higher risks of allergies, asthma, infections, and immune problems later on. The study showed that even small amounts of microplastics could alter this delicate process.

Breast milk is still the best nutrition for babies despite this finding. To reduce microplastics in your milk, avoid plastic food and drink containers, filter your water, and eat fewer packaged and processed foods. Store expressed breast milk in glass bottles.