97. Perfluorinated alkyl substances in Canadian human milk as part of the Maternal-Infant Research on Environmental Chemicals (MIREC) study (lay summary)

Rawn DFK, Dufresne G, Clément G, Fraser WD, Arbuckle TE. Science of the Total Environment 2022 Mar 30:154888. doi: 10.1016/j.scitotenv.2022.154888

Perfluorinated alkyl substances (PFAS) are a group of several thousand human-made chemicals that have been widely used to make various products.  For example, to keep food from sticking to cookware, make clothes and carpets resistant to stains, and create firefighting foam that is more effective.  They are found in certain cosmetics and in some food packaging materials.  As they have been widely used and persist in the environment, most people have low levels of PFAS in their blood.  Scientific studies have shown that higher exposure to some PFAS such as PFOA and PFOS in the environment may be linked to harmful health effects in humans.

The objective of this study was to measure PFAS in 664 breast milk samples from MIREC participants.  Seven PFAS chemicals were measured and summed.  The summed PFAS concentrations ranged from 3.1 ng/L to 603 ng/L, with a median of 106 ng/L.  The main PFAS found were PFOA and PFOS.  Women having their first child had higher levels of summed PFAS in breast milk.

These data are the first pan-Canadian data on PFAS in human milk.  PFOS and PFOA levels were similar to what has been measured in the USA, but lower than levels measured in a Spanish study.

In conclusion, despite the presence of low levels of environmental contaminants in human milk, Health Canada supports breastfeeding due to the benefits to both infants and mothers.