Forever Chemicals in Breast Milk

Last week, The Guardian published an article with this headline: Study Finds Alarming Levels of ‘Forever Chemicals’ in US Mothers’ Breastmilk. Perhaps not surprisingly, breastfeeding people were…alarmed. Should they be? Here’s the link to the original study. In this project, researchers collected breastmilk from 50 women and tested it for a class of chemicals know as PFAS (per- and polyfluoroalkyl substances). This is a group of chemicals which was historically commonly used in manufacturing. Due to concerns about their health and environmental impacts, some of these chemicals have been phased out of manufacturing over time, and levels in the bloodstream have dropped on average. However, some forms of these chemicals are still in use and their persistence means they are in our bloodstream. The new study reports several findings. First, they find evidence of a number of chemicals in this class in breastmilk. This isn’t surprising; we know these are present in the bloodstream and we would expect transfer through milk. And, in fact, existing data has shown this. The authors also show what I think are two pieces of “good” news (I mean, relatively good? But this my spin, not theirs). First, most of the evidence they put together shows the rates of these chemicals in milk going down over time. This is likely due to the phase out of their use in manufacturing. That’s a good sign! Second, they show that the implied exposure levels are lower than reference doses set by the EPA (these “reference doses” are levels of implied concern). Stepping back, it is important to ask what the possible health risks are here? Existing data shows that higher levels of these chemicals are associated with cholesterol issues, asthma and possibly age of puberty. This review is helpful. Chemical levels do not seem to be associated with neurodevelopment outcomes (i.e. IQ or behavior problems) and several other health measures. Although the study reported on by The Guardian mentions a link with cancer, that seems to show up in people who work in manufacturing with these compounds. The most consistent link for normal exposure in children is with the cholesterol-related measures. As with virtually everything in this space, it is difficult to be confident on causality here since exposure to these chemicals correlates with other confounding factors. Bottom line: these type of chemical appear in breastmilk; they are appearing less over time due to phase out of the use of these; the levels are lower than EPA limits. On the flip side, existing work does make it seem like there are some possible health risks, if not enormous ones. So…should you be alarmed? I guess you can always be alarmed if you would like to be! But I’ll say two things. First, the bottom line findings here do not, to me, rise to level of alarming. I might go with “worth further study” or “notable”. But the paper didn’t find levels which outpaced what the EPA considers acceptable, they appear to be declining over time, and the consequences are a little vague. Second: there isn’t really anything you can do about this. So, while it is fine to be alarmed, it’s not obviously useful. You could stop breastfeeding, but virtually no one is likely to suggest that’s the right solution, given how much everyone likes breastfeeding. There likely isn’t any short-term behavior you can undertake to lower your chemical levels. And even things like “advocate for less use of these chemicals in manufacturing” is less relevant here, since these are already being phased out to a large extent. In the end, I think I’d personally put this in my favorite parenting-anxiety bucket. Maybe, just try not to think about it.

Forever Chemicals in Breast Milk

A new study raised alarm—but should you worry?

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