“Forever chemicals” that linger in the environment and our bodies have been linked to liver damage in a new study published in the journal Environmental Health Perspectives.
The chemicals – called per- and polyfluoroalkyl substances or PFAS – are a band of thousands of synthetic chemicals used in a wide range of everyday products, from waterproof clothing and pizza boxes to make-up and non-stick frying pans. Since they take a long time to break down and accumulate in the environment and in human tissue, PFAS are often called “forever chemicals.”
Their impact on humans is still debated, but this latest meta-analysis adds to the mounting evidence that these lingering chemicals do indeed take their toll on our health.
In the latest study, scientists looked at data from over 100 previous studies involving both humans and rodents to examine whether PFAS exposure was linked to elevated levels of alanine aminotransferase (ALT) a liver enzyme that indicates liver damage is occurring.
In particular, three of the most commonly detected PFAS in humans – perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and perfluorononanoic acid (PFNA) – were all connected with elevated levels of ALT.
Worryingly, evaluated ALT levels are tightly linked with non-alcoholic fatty liver disease, a condition where excess fat builds up in the liver. According to the study authors, this linked to PFAS may explain why non-alcoholic fatty liver disease has mysteriously been on the rise in recent years.
“We see that the prevalence of NAFLD [non-alcoholic fatty liver disease] in humans is increasing but the explanations are unclear,” Sarah Rock, lead study author and a PhD student in the department of population and public health sciences at the Keck School of Medicine, said in a statement.
“Though the human research connecting PFAS to liver disease is limited, there is much evidence in animal research showing hepatotoxicity of PFAS. A challenge for PFAS researchers is that humans are exposed to mixtures of hundreds if not thousands of these chemicals. Mixture analyses is one potential tool for addressing this complexity in the future.”
PFAS are everywhere in the environment – discovered in rain, snow, groundwater, tap water, rivers, seawater, and even air. Due to their prolific and hardy nature, it's thought that all adults in the US have detectable levels of PFAS in their bodies.
One of the chief concerns surrounding PFAS is their ability to interfere with hormones. Many believe this could be having a range of effects on human health, most notably in regards to fertility. The researchers also suspect this link to hormone disruption may be playing a role in the liver damage seen in their latest study, primarily because they noted some differences in the effects of PFAS on liver injury between females and males.
“This research clearly shows that PFAS need to be taken seriously as a human health concern because even after they are phased out, they persist in the environment,” explained Elizabeth Costello, another lead study author and PhD student in the department of population and public health sciences at the Keck School of Medicine.
“There is enough evidence, we believe, to demonstrate a need to clean up sources of exposure to PFAS and to prevent future exposures.”