New Study Examines PFAS in Breast Milk Using LC-MS/MS

A recent study sought to expand on previous lipidomics research to explore whether and how exposure to per- and polyfluoroalkyl substances (PFAS), as measured in breast milk, affect the human milk metabolome and specifically the nutritive quality of milk. The research team studied associations between perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) concentrations and metabolomic profiles in breast milk among participants in the New Hampshire Birth Cohort Study (NHBCS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was utilized. To the team’s knowledge, their study is among the first to characterize the human milk metabolome in relation to PFAS exposure and is the first to do so in such a large, contemporary, well-characterized cohort (425 participants with milk samples). A paper reporting on the research team’s findings was published in Environmental Epidemiology (1).

A class of over 12,000 synthetic chemicals that make consumer and industrial products water and oil resistant (2), many PFAS resist degradation and can persist in the environment due to their chemical composition, and, as a result, are in our bodies for decades (3).

Breast milk is made of a wide range of bioactive components. Nearly 50% of the total energy content of breast milk is fat, with 95%–99% of the fatty acids within triglyceride structures (4). Although research has shown associations between levels of PFAS in cord blood and changes in the human milk lipidome (5,6), the authors of the article state that there have been no studies evaluating the relationship between PFAS concentrations in human milk and the metabolic composition of milk, including both lipid and nonlipid components that provide vital contributions to growth, development, and energy for infants (1).

The analysis of milk for the study was performed by the Minnesota Children’s Health Exposure Analysis Research (CHEAR) Hub using protein precipitation followed by centrifugation, concentration, and analysis using LC-MS/MS to quantify concentrations of PFOA, PFOS, perfluorohexane sulfonate (PFHxS), perfluorononanoate, perfluorodecanoate, perfluoroundecanoate, perfluorobutane sulfonate, perfluoroheptanoate, perfluoroheptane sulfonate, and perfluorohexanoate (1).

The researchers state that they observed five nutritional profiles, including neutral, high fatty acid, high glycerophospho- and sphingolipids, low fatty acid, and high lactose and creatine phosphate. Elevated levels of PFOA were associated with high fatty acid levels, providing additional mechanistic support that PFAS are transferred into milk in the same manner as triglyceride fatty acids. Elevated PFOA levels were also associated with profiles suggesting less healthy milk fat globule membrane formation and decreased milk production. The researchers state that future studies should explore PFAS associations with milk volume and further interrogate the mechanisms by which PFAS are transferred from the plasma of lactating individuals into breast milk (1).

Manual breast pump and bottle with breast milk on the background of mother holding in her hands and breastfeeding baby. © evso - stock.adobe.com

References

1. Criswell, R. L.; Bauer, J. A.; Christensen, B. C.; Meijer, J.; Peterson, L. A.; Huset, C. A.; Walker, D. I.; Karagas, M. R.; Romano, ME. Associations of Per- and Polyfluoroalkyl Substances with Human Milk Metabolomic Profiles in a Rural North American Cohort. Environ. Epidemiol. 2024, 8 (6):e352. DOI: 10.1097/EE9.0000000000000352

2. Cousins, I. T.; Vestergren, R.; Wang, Z.; Scheringer, M.; McLachlan, M. S. The Precautionary Principle and Chemicals Management: The Example of Perfluoroalkyl Acids in Groundwater. Environment International 2016, 94, 331–340. DOI: 10.1016/j.envint.2016.04.044

3. Kotthoff, M.; Muller, J.; Jurling, H.; Schlummer, M.; Fielder, D. Perfluoroalkyl and Polyfluoroalkyl Substances in Consumer Products. Environ. Sci. Pollut. Res. 2015, 22, 14546–14559. DOI: 10.1007/s11356-015-4202-7

4. Kim, S. Y.; Yi, D. Y. Components of Human Breast Milk: From Macronutrient to Microbiome and MicroRNA. Clin. Exp. Pediatr. 2020, 63 (8), 301–309. DOI: 10.3345/cep.2020.00059

5. Hyotylaninen, T.; Ghaffarzadegan, T.; Karthikeyan, B. S. et al. Impact of Environmental Exposures on Human Breast Milk Lipidome in Future Immune-Mediated Diseases. Environ. Sci. Technol. 2024, 58, 2214–2223. DOI: 10.1021/acs.est.3c06269

6. Lamichhane, S.: Siljander, H.; Duberg, D. et al. Exposure to Per- and Polyfluoroalkyl Substances Associates with an Altered Lipid Composition of Breast Milk. Environ. Int. 2021, 157, 106855. DOI: 10.1016/j.envint.2021.106855