Breastfeeding exposes babies to water- and stain-proofing chemicals


Chemicals that have been linked to child immune system problems transfer from mother to baby during breastfeeding

August 20, 2015

By Brian Bienkowski
Environmental Health News

Breastfeeding appears to expose infants to a group of industrial chemicals linked to immune system problems, according to a study released today.

The study is the first to estimate the transfer of water- and stain-proofing chemicals from mother to baby during breastfeeding and suggests that the mother’s milk—which provides healthy antibodies, vitamins and nutrients— is also a major source of these harmful compounds for the developing children.
Philippe Grandjean

“It’s a very unwelcome surprise that these compounds that we’re just beginning to understand to be toxic actually transfer through human milk to the most vulnerable population group,” said Philippe Grandjean, a professor of environmental health at the Harvard T.H. Chan School of Public Health and co author of the study published today in Environmental Science and Technology.

Grandjean and researchers from Denmark and the Faroe Islands looked at five types of perfluorinated alkylate substances, or PFASs, in the blood of 81 children who were born in the Faroe Islands between 1997 and 2000. They checked the children’s blood at ages 11 months, 18 months and 5 years old, and checked their mother’s blood at week 32 of pregnancy.

They found that children who were exclusively breastfed had levels of the chemicals increase about 20 to 30 percent each month. Children who were only partially breastfed had smaller increases.

One limitation was that they calculated rather than measured levels of the compounds in children at birth, said Glenys Webster, an epidemiologist and post-doctoral fellow at Simon Fraser University. They also did not measure chemical levels in breast milk. But, the pattern they found was compelling and exposure of any kind at such a young age may be of concern, Webster said.

"During the prenatal period and early infancy we are quite sensitive to lots of different exposures," she said.

The findings "highlight the importance of not having these in consumer products,” said Simona Balan, senior scientist with the Green Policy Institute based in Berkeley, California, who was not involved in the study.

Webster said that while this is evidence that breast milk can be a contributor to chemical exposure, breastfeeding is still healthy for babies.

"There are many important benefits of breastfeeding, which still far outweigh the risks," she said. "The real question is how do we reduce moms' exposures in the first place?"

Perfluorinated chemicals have a half-life in people’s bodies of more than three years, which is a long time and makes it difficult for women who might get pregnant to avoid exposure, Balan said. In the current study, the results suggested that several months of breastfeeding lowered the mothers levels of the compounds, presumably transferring to the baby.  

The compounds also are not fat or water soluble, and are widely used in products such as waterproof clothing, food packaging, paints and lubricants [think Teflon, Gore-Tex and Scotchgard] to make them nonstick and water resistant.

Researchers have found the compounds in people all over the world, Grandjean said.

"There are many important benefits of breastfeeding, which still far outweigh the risks."-Glenys Webster, Simon Fraser UniversityThere are two types — long chain and short chain, the latter having fewer carbons.

Long-chain compounds, such as perfluorooctanoate (PFOA) and perfluorooctane sulfonic acid (PFOS) are more heavily studied, linger longer in the human body, and have been linked to testicular and kidney cancers, low birth weights, obesity, thyroid disease, high cholesterol and hypertension and low birth weights.

In laboratory animal studies, long chain forms of the chemicals have disrupted immune and endocrine systems, harmed brains and caused tumors.

Three years ago, using this same cohort of children from the Faroe Islands, Grandjean and colleagues reported that exposure to perfluorinated compounds was linked to reduced immune responses in the children at ages 5 and 7.

Jessica Bowman—executive director of the FluoroCouncil, a trade association representing fluorinated compound manufacturers—pointed out that the current study examined long-chain compounds, which are being phased out by members of the council.

“Over a decade ago, FluoroCouncil members started working with U.S. EPA and other regulators to globally phase-out all long-chain PFAS chemistries by the end of 2015," she said in an emailed response. “To help support that phase-out, our member companies developed alternatives, based on short-chain PFAS. The alternatives are some of the most robustly-studied new chemicals introduced into the market."

While they may be less persistent, scientists know "very little" about the toxicity of the short-chain alternatives, Webster said. 

Long-chain perfluorinated compounds are “incredibly stable,” Grandjean said. Even with phase-outs, the compounds will persist as they break down very slowly in the environment.

"They're in the marine food chain, they're circulating in oceans ... it's a pervasive and persistent problem." Grandjean said.

"We need to ask 'are we doing the right thing with regards to chemical control, and can we do it better?' Surprises like this shouldn't happen in the future."-Philippe Grandjean, Harvard School of Public HealthPFOS is regulated as a persistent organic pollutant in the European Union, and PFOA is restricted in Norway and there's a proposal to include it under the European Union’s chemical regulation program (REACH).

The U.S. EPA in January of this year proposed requiring manufacturers to let the agency know 90 days in advance if they planned on using certain long-chain fluorinated compounds, so the agency could evaluate if the use is necessary.

The chemicals have increasingly been on scientists’ radar. In May, more than 200 scientists outlined potential health concerns from fluorinated chemicals and urged for replacements and tightened regulations in a report dubbed the “Madrid Statement,” which Balan co authored.

Grandjean said that the passage of chemicals via breast milk is not included in the testing of environmental chemicals, and pointed out that it took researchers many years to discover such transfer with other harmful chemicals such as dioxins, polychlorinated biphenyls (PCBs) and flame-retardants.

“My hope is that this is the last one, but that isn’t a realistic hope,” he said, adding that the timing of this study is critical as U.S. Congress continues to discuss reforms to the nation’s Toxic Substances Control Act, which regulates chemicals.

“We need to ask 'are we doing the right thing with regards to chemical control, and can we do it better?'” Grandjean said. “Surprises like this shouldn’t happen in the future.”

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For questions or feedback about this piece, contact Brian Bienkowski at


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