Forever chemicals: New study begins to unravel exactly how PFAS affect our bodies

Per- and poly-fluoroalkyl substances (PFAS) have made their way everywhere. These chemicals can be found in the blood of nearly all humans, including unborn babies, and have been found as far afield as Antarctica.

This large group of chemicals, united by the fact they all have multiple carbon-fluorine bonds, are extremely long-lived, earning them the nickname of “forever chemicals”.

What are PFAS used for?

In addition to being immortal, PFAS are extremely useful. They are widely used in industrial processes and fire-fighting foams and are found in countless consumer goods, such as food wrappers, waterproof materials, stain-proof materials, non-stick cookware, and some cosmetics.

What are the potential health effects?

Unfortunately, there is a rather large list of diseases that become more likely if enough of these chemicals accumulate inside humans. These include thyroid disease, increased cholesterol levels, liver damage, various cancers, and pregnancy-induced hypertension.

Despite knowing that high levels of PFAS are a risk factor for many health conditions, the way in which these chemicals lead to disease is less well-understood.

Scientists have tried to answer this question, but many of the studies look at the effect of only single chemicals under the PFAS umbrella. As we are exposed to potentially thousands of different PFAS in our day-to-day lives, it is clear looking at just single chemicals isn’t giving us the whole picture.

New insights into the metabolic effects of PFAS

A recent study at the Keck School of Medicine has improved our understanding of how these chemicals work by studying the effects of PFAS on human metabolism. Crucially, the study did this by examining blood samples from volunteers, meaning the team will be considering the impact of the mixture of PFAS that the participants have accumulated naturally from the environment, and any synergy between different PFAS will be included in the results.

The scientists took blood samples from two groups of participants. One cohort consisted of 312 Hispanic children with an average age of 11, and the other was made up of 137 young adults with an average age of 19.

The researchers analysed the blood samples for the presence of six common PFAS. They also measured the levels of different naturally occurring metabolites in the blood, which allowed the researchers to infer if any metabolic pathways were more or less active than expected. Five of the six PFAS tested for were found in all participants, with the remaining chemical found in around 99% of participants.

The data revealed that there was a link between PFAS levels and changes to the participants’ natural metabolic function. In particular, PFAS seemed to alter the metabolism of amino acids and lipids, and exposure to these chemicals also appeared to cause an increase in the levels of the main thyroid hormone.

What does this mean?

Altered metabolic function in early life can lead to increased chances of metabolic disorders and cardiovascular disease. During puberty, thyroid hormones are especially important, as they help to regulate growth and metabolism.

Developing children are incredibly sensitive to fluctuations in these hormones, and changes to natural levels at this stage in life can have profound effects on the course of future diseases such as diabetes, cardiovascular disease, and cancer.

Interestingly, the authors also note that they didn’t find any evidence of these changes being caused by single chemicals. Rather, the change in natural processes was linked to mixtures of chemicals.

What next for the “forever chemicals”?

This is the first research which examines in detail the effects of combinations of PFAS on human metabolism, and the results may help scientists to work out how exactly exposure to these chemicals can lead to disease.

The authors also suggest that their findings lend support to the argument that PFAS should be regulated as a chemical class, rather than being regulated on a chemical-by-chemical basis as they currently are. Although this would be unpopular with the companies using these chemicals extensively, the mounting medical evidence makes it clear regulatory agencies need to do more to protect us from the harmful effects of these “forever chemicals”.