A new study built entirely on samples from Seattle-area moms found hormone-disrupting chemicals in the majority of their breast milk — but researchers are quick to say that’s not a reason to stop breastfeeding. The new research was published in the Journal of Exposure Science & Environmental Epidemiology in April.
Investigators from the University of Washington, Seattle Children’s Research Institute, Toxic-Free Future, and Emory University tested milk from 50 Washington women collected back in 2019 and detected BPA (in 74% of samples), its chemical cousin BPS (78%), the antimicrobial triclosan (62%), and melamine at similarly high rates when they tested the breast milk. All four are classified as endocrine disruptors, meaning they can interfere with how the body’s hormones function even in small amounts.
Bigger source than dust
According to the study authors, breastfeeding is a greater source of exposure to BPA, BOS, triclosan, and melamine than other routes, such as skin contact (“generally higher than for other exposure pathways, e.g., dermal uptake, dust ingestion or inhalation,” to be exact).
“These findings show that infants and their mothers are being exposed to hormone-disrupting chemicals used in everyday products, including plastics, during critical stages of development,” said Dr. Ryan Babadi, MPH, science director for Toxic-Free Future, in a release. “These exposures highlight the need for stronger safeguards so families are not put in harm’s way simply by feeding their babies.”
Breast is still best
None of that changes the researchers’ bottom line on the importance of breasfeeding: In the same announcement, Dr. Sheela Sathyanarayana, the study’s senior author and a UW pediatrics professor, said the study doesn’t erase the many benefits of breast milk.
“As a pediatrician, I am concerned about the detection of chemicals in breast milk and impacts on infant development,” Sathyanarayana said. “Detection of these contaminants does not take away from the major health benefits of breast milk for infants, including immune factors that help prevent infections.
Instead, Sathyanarayana said, the study is a call to action: “As a society, it’s important to try to work together to eliminate these chemical exposures.”
Washington ‘had led the way’
There’s already some movement on this front. Since the milk in this study was collected, Washington has banned BPA and related chemicals from beverage cans and, as of this January, from receipt paper too — part of a state law that identifies harmful chemicals in consumer products and phases them out over time. Melamine isn’t on that list yet.
“Washington state has led the way on safer chemicals, but the presence of these chemicals in breast milk shows we need to do more to protect public health,” said Babadi.
This new research is not the first time Seattle moms’ milk has been put under the microscope. Since 2019, the same breast milk samples have been tested in several studies, showing that it also contains PFAS “forever chemicals,” flame retardants, and disinfectant compounds called quaternary ammonium compounds.
Congress looks at loosen toxic substance control
The study lands just as lawmakers in Washington, D.C. weigh changes to the Toxic Substances Control Act — the main federal law meant to keep dangerous chemicals in check. Critics say the proposed changes would loosen rather than tighten the rules. A newly formed coalition of more than 85 health and safety organizations, called the Alliance for Health and Safe Chemicals, has come out against the proposal, arguing it would make it easier for cancer-linked chemicals to show up in places kids spend their days: homes, schools, workplaces. More on that warning here.
“We need stronger protections from toxic chemicals, not rollbacks that put our health at risk,” said Babadi. “As the chemical industry pushes to weaken federal protections on chemicals that can harm our health, this study underscores the urgent need to prevent the use of toxic chemicals and stop exposures.”
TAKE ACTION: Do you have an opinion in whether or not Congress should loosen or tighten the rules around keeping toxic substances and chemicals in check? Contact your members of Congress to make your voice heard.
