Potentially toxic chemicals found in everyday products, including fast-food wrappers, makeup and carpeting, are altering hormonal and metabolic pathways needed for human growth and development, according to a new study.
Researchers analyzed study samples from young children, teens and young adults, all of whom had a mixture of different synthetic compounds called perfluoroalkyl and polyfluoroalkyl substances — or PFAS — in their blood, including PFOS, PFOA, PFHxS, PFNA, PFHpS and PFDA.
The US Environmental Protection Agency recently announced historic rules strictly controlling levels of several of these chemicals in the nation’s drinking water.
“Exposure to a combination of PFAS not only disrupted lipid and amino acid metabolism but also altered thyroid hormone function in the children,” said lead author Jesse Goodrich, assistant professor of population and public health sciences at the University of Southern California’s Keck School of Medicine.
For children to properly develop, the thyroid makes two key hormones that play a role in blood pressure control and how the body makes and uses protein, fats and carbohydrates, the Mayo Clinic noted. These chemical messengers “affect every cell in the body,” according to the website.
Amino acids are needed to make enzymes, hormones, proteins and other needed molecules, while lipids control how vitamins are stored, assist in hormone production and regulate how fat is turned into energy and used or stored.
“This study is doing an in-depth analysis of how PFAS exposure is not just impacting hormone levels in humans, but impacting different metabolic pathways as well,” said David Andrews, a senior scientist at the Environmental Working Group, an advocacy group that has created a national map of PFAS-contaminated sites.
“Changes in these metabolic markers can be indicative of a number of different health outcomes in the future for the children, such as an increased susceptibility to obesity, insulin resistance, increased risk for fatty liver disease and potentially cancer,” said Andrews, who was not involved in the study.
The research, published in the journal Environmental Health Perspectives, had a unique finding as well: Results showed a combination of six PFAS had a more pronounced impact on metabolism and hormone function than any one alone.
“That’s important because most people carry a mixture of the chemicals in their blood,” Goodrich said. “We believe no other studies have looked at this mixture of chemicals in children and how it impacts metabolic pathways.”
What are PFAS?
In use since the 1950s, PFAS are chemicals most Americans have in their blood, according to the Agency for Toxic Substances and Disease Registry, which is charged with protecting the US public from hazardous substances.
Often called “forever chemicals” because they do not easily break down in the environment, PFAS are used in food packaging to prevent grease and water from soaking through food wrappers and beverage cups. The chemicals are also used to make carpeting, clothing and furniture resistant to stains, water and grease damage. Other uses include nonstick cookware, cell phones, commercial aircraft and low-emission vehicles.
Some of the most studied PFAS, such as perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) have been linked to high cholesterol, kidney and other cancers, ulcerative colitis, thyroid disease or dysfunction and many more health conditions.
Public concern led to a commitment by manufacturers in 2008 to phase out use of those two chemicals in American products. However, “as PFOS and PFOA are phased out and replaced, people may be exposed to other PFAS,” the Agency for Toxic Substances and Disease Registry noted.
Studies are now finding the same health impacts from some of the newer PFAS versions, according to the National Academies of Sciences, Engineering, and Medicine, which has called for people at higher risk, such as pregnant women, young children and the elderly, to be tested for a subset of PFAS chemicals.
Due to their long half life and use by manufacturers outside the United States, PFOA and PFOS can still be found in imported products and in the soil and water of American communities.
Changes persisted
Researchers used high-resolution mass spectrometry to study the impact of PFAS on metabolism, said coauthor Dr. Lida Chatzi, a professor of population and public health sciences at USC’s Keck School of Medicine.
“Traditional approaches measure one chemical at a time,” she said. “This technology lets us measure every single chemical that’s in the blood — over 10,000 — and get this very, very detailed view of what’s happening in the body.”
One set of blood samples came from 312 overweight or obese children between 8 and 13 who were participating in the Study of Latino Adolescents at Risk (SOLAR) in Southern California between 2001 and 2012.
The vast majority of the children in this group had not entered puberty, which makes the impact of PFAS on their metabolism even more concerning, Goodrich said.
“Puberty is a critical time for the development of many different organs and tissues,” he said, “so the fact we’re seeing these changes before puberty may be setting the stage for many diseases later in life.”
Another 137 young adults between the ages of 17 and 23 participating in the Southern California Metabolic and Asthma Incidence Research (Meta-AIR) study also provided blood samples between 2014 and 2018.
Despite the lengthy time span between the two groups, the blood of all 449 youth showed signs of metabolic changes due to PFAS exposure, illustrating the extensive half-life of these forever chemicals, Chatzi said.
“These early metabolic changes from PFAS exposure persist into early adulthood,” Chatzi said. “The effects are the same even though the mixtures of the PFAS differ, which bolsters the belief that these chemicals need to be banned as a class instead of one by one.”
Couldn’t these changes be due to other processes in the body?
“Yes, there are other factors that are associated with similar changes such as age, socioeconomic factors, body mass, puberty status and more,” Goodrich said. “We took all of those factors into account in the analysis in order to provide additional evidence that PFAS are what’s really driving these changes.”
What can parents and caregivers do?
There are ways to reduce exposure to PFAS in the home. Look up levels of PFAS in your local public water system with the Environmental Working Group’s national tap water database searchable by zip code. If levels are concerning, consumers can purchase a water filter for their tap — experts say reverse osmosis filters are the most reliable. NSF, formerly the National Sanitation Foundation, has a list of recommended filters.
Experts suggest avoiding stain-resistant carpets, upholstery and waterproofing sprays, along with nonstick cookware. Use cast-iron, stainless steel, glass or enamel products instead. Check labels for the ingredient polytetrafluoroethylene, or PTFE, or other “fluoro” ingredients and avoid those as well.
Don’t eat microwave popcorn or greasy foods wrapped in paper, and boycott takeout containers and other food packaging. Instead cook at home, and eat more fresh foods.
Makeup and personal care products also contain PFAS to condition, smooth or make skin appear shiny. Start by avoiding cosmetics labeled as “wear-resistant” or “long-lasting,” which a 2021 study found have the highest levels of PFAS compounds. Choose uncoated nylon or silk dental floss or one that is coated in natural wax. You can also check a database on personal care products with toxins created by the Environmental Working Group.
