Mercury From Dental Fillings Ends Up in Breast Milk

Mercury from your old dental fillings is getting into your breast milk. A 2026 study found that every single breastfed infant tested was exposed to mercury above the safe reference dose.

What's actually in it

Amalgam dental fillings — the silver ones — are about 50% mercury by weight. Dentists have used them for 150 years. The mercury doesn't just sit there. It off-gases as vapor, absorbs into your body, and accumulates in tissues including breast tissue.

That's the pathway. Mercury vapor from fillings enters your bloodstream. When you're breastfeeding, it ends up in your milk.

What the research says

A 2026 study in Food Chem Toxicol measured mercury in the breast milk and fingernails of 74 breastfeeding mothers. Every subgroup had a target hazard quotient greater than one — meaning mercury exposure exceeded the safe daily reference dose for their infants.

Dental filling history was a statistically significant predictor of mercury in breast milk. Infants with higher mercury exposure had lower body weight (r = -0.327, p = 0.002).

Mercury affects developing brains. Even low levels during infancy can impact cognitive development.

If you're breastfeeding, ask your dentist about your filling type. Avoid getting new amalgam fillings placed or removed while pregnant or nursing. See non-toxic baby products for more on protecting your infant from environmental toxins.

Also see glass food storage for safer alternatives.

Source: Dahmardeh Behrooz R, et al. (2026). Food Chem Toxicol.