Microplastics found in human breast milk for the first time

Our addiction to plastic goods has led to contaminants entering human placentas, blood, and now even breast milk

By Matthew Rozsa

Staff Writer

Published October 11, 2022 5:28PM (EDT)

Mom breastfeeding a baby (Getty Images/istetiana)
Mom breastfeeding a baby (Getty Images/istetiana)

Microplastics, the shed microscopic particles of larger plastic goods, are both invisible and everywhere. Because synthetic plastic polymers are used to make thousands of commonly used products, there are trillions of these tiny plastic particles — known as microplastics — on our planet. They are in the ocean and embedded in our soil. They irritate our bowels and shoot through our bloodstream.

Now, they've been sighted in one part of the body they had never been observed before: in human breast milk. 

"In fact, the chemicals possibly contained in foods, beverages, and personal care products consumed by breastfeeding mothers may be transferred to the offspring, potentially exerting a toxic effect."

Indeed, a recent study in the scientific journal Polymers, conducted by Italian scientists, analyzed breast milk taken from 34 healthy mothers one week after they gave birth in Rome. The researchers then analyzed the breast milk to determine if there were microplastics present — and, in 75% of the cases, there were. When combined with the knowledge that microplastics have been found in human placentas, the authors argue, these results should raise a red flag.

While adults are already developed and grown, infants are a far more vulnerable population — and it is unknown the effect that ingesting such contaminants might cause in them, the authors note. "In fact, the chemicals possibly contained in foods, beverages, and personal care products consumed by breastfeeding mothers may be transferred to the offspring, potentially exerting a toxic effect," they continue. 

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While the appearance of microplastics in breast milk is alarming, it should not discourage mothers from breastfeeding. Notably, microplastics are apt to appear in the bottles and other plastic products from which baby formula is sold, so it is not like a breast milk substitute will necessarily be better. More important, though, is the fact that there are natural advantages to breastfeeding.

"It must be stressed that the advantages of breastfeeding are much greater than the disadvantages caused by the presence of polluting microplastics," Dr Valentina Notarstefano at the Università Politecnica delle Marche, one of the study's co-authors, told The Guardian. "Studies like ours must not reduce breastfeeding of children, but instead raise public awareness to pressure politicians to promote laws that reduce pollution."

The recent study adds to the considerable body of research on the ways in which microplastics have squirreled their way into the human body, often with studied detrimental effects. Plastics often contain chemicals known as phthalates, which has been linked to cancer in children, and bisphenols, which are linked to reproductive health issues. The average American consumes roughly one credit card worth of plastic each week because of microplastics, and experts like environmental health scientist Dr. Shanna Swan have linked plastic pollution to decline sperm counts.

When scientists realized that plastic pollution had made it into the human bloodstream, they said that this means it is not being eliminated through the kidneys, liver and other organs that would normally slow the rate of absorption for foreign particles like this. In turn, that means that microplastics could reach any organ — and do unpredictable amounts of damage.

"If plastic particles present in the bloodstream are indeed being carried by immune cells, the question also arises, can such exposures potentially affect immune regulation or the predisposition to diseases with an immunological base?" the authors of that study asked.

Because microplastics are particularly prevalent in our waterways, this means they are also will disproportionately impact the economic lives of people who depend on our oceans.

"We also know that we have these areas, where a lot of this plastic waste is persisting and collecting, in coastal communities, right at the ends of waterways entering our oceans, and those are areas where you have a lot of communities that depend highly on fishing for their livelihoods and food," Erin Simon, head of plastic waste and business at the World Wildlife Fund (WWF), told Salon last year. "And because of the increase of plastic rates, they're having to travel further off shore. It costs them more in fuel and it means they may make less money. They may not be able to provide that for their family."

By Matthew Rozsa

Matthew Rozsa is a staff writer at Salon. He received a Master's Degree in History from Rutgers-Newark in 2012 and was awarded a science journalism fellowship from the Metcalf Institute in 2022.

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Aggregate Breast Milk Breastfeeding Health Lactation Microplastic Plastic