PFAS Can End Up in Breast Milk, and Rice and Red Meat May Be Prime Sources
Eggs, tea and tomatoes were linked with high PFAS levels in breast milk, too.
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People who consume high amounts of certain foods during pregnancy may have high levels of “forever chemicals” in their lactation milk, according to a recent study published in Science of the Total Environment.
After assessing the diets and milk samples of 426 participants, researchers from Dartmouth College found that a higher intake of white rice, red meat, eggs, tea and tomatoes during pregnancy was associated with higher lactation concentrations of perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) – 2 of the most harmful per- and polyfluoroalkyl substances (PFAS).
PFAS in food, PFAS in milk
PFAS contamination is a mounting issue around the world. The group of surfactants were first mass produced in the mid-20th century to waterproof consumer products like pans, paints and packaging. They’re now known as forever chemicals because they have an almost-unbreakable highly fluorinated alkyl chain backbone that makes them extremely chemically stable, and difficult to degrade naturally.
This robustness is all the more troubling considering the recent wave of research linking the chemicals to cancers, high cholesterol and low birth weights. Avoiding them doesn’t seem to be an option, either; most Americans already have some levels of PFAS in their blood, according to the US Department of Health and Human Services.
But some people may still be more exposed to PFAS than others depending on their location and the kind of food and beverages they consume. Recent research from the Dartmouth College group found that seafood, particularly lobster and other crustaceans, can host high levels of PFAS.
To see if such products and other foodstuffs could confer PFAS into human breast milk, the researchers accessed data from the New Hampshire Birth Cohort Study, an ongoing study involving over 3,000 participants who were enrolled while pregnant. Between 2013 and 2018, 426 of the participants provided milk samples when 6 weeks postpartum.
These samples were then tested for PFAS levels, and the results were compared with the participants’ responses to a dietary questionnaire.
A higher intake of white rice, red meat, eggs, tea and tomatoes during pregnancy was associated with higher PFOS and PFOA concentrations in the milk samples.
PFOS and PFOA
PFOS and PFOA are two of the most notorious PFAS chemicals, having been linked to cancers, high cholesterol and birth defects.
Rice appeared to be the food most packed with two forever chemicals. After performing a statistical analysis, the researchers found that an increased serving per day of white rice during pregnancy was associated with a 7.5 % and 12.4 % higher milk PFOS and PFOA concentration, respectively.
Rice crops can absorb PFAS from tainted soil, but contamination can also occur when the grains are boiled in PFAS-contaminated water or cooked and stored in PFAS-coated cookware and containers.
Red meat and eggs appeared to be the next two significant sources of PFAS. Every increased serving/day of eggs or red meat was associated with 7.2 % and 9.3 % higher milk PFOS concentration, while one more serving/day of tea or tomatoes was associated with 5.9 % and 6.4 % higher milk PFOA level.
Previous research has suggested that teabags are a prime source of PFAS contamination.
As for seafood – the food source commonly associated with PFAS – the Dartmouth researchers made a surprising finding: while greater seafood consumption was associated with higher PFAS levels in the blood of participants, this contamination was largely absent from the same participants’ milk samples. The researchers say a better understanding of the biological mechanisms underpinning milk transfer of PFAS is needed to elucidate this finding.
For now, the researchers advise anyone worried about breastfeeding to push ahead despite the PFAS concerns. The known harms associated with such PFOS and PFOA contamination, they say, still pale to the boons of breastmilk.
“It seems like the benefits of breastfeeding really outweigh the risks of any kind of potential contamination, that’s certainly the Centers for Disease Control stance and the World Health Organization stance at the present moment,” Megan Romano, one of the researchers of the study and an associate professor of epidemiology at Dartmouth’s Geisel School of Medicine, told Technology Networks.
“But we definitely want to learn more about this. And it’s the question that I most commonly get asked by women who live in contaminated communities. ‘Is it safe for me to breastfeed? Should I be breastfeeding?’ We’d like to be able to give them better guidance and more satisfying answers,” Romano concluded.
Romano was speaking with Leo Bear-McGuinness, Science Writer and Editor at Technology Networks.
Reference: Wang Y, Gui J, Howe CG, et al. Association of diet with per- and polyfluoroalkyl substances in plasma and human milk in the New Hampshire Birth Cohort Study. Sci of the Total Environ. 2024. doi: 10.1016/j.scitotenv.2024.173157
About the interviewee
Megan Romano is an associate professor of epidemiology at the Dartmouth Geisel School of Medicine. Her research and the work of her lab, the Romano Lab, primarily explores the effects of environmental endocrine disrupting chemicals exposure during the sensitive windows of pregnancy and gestation, on breastfeeding and early life growth.
