New research on “forever chemicals” called PFASs has added to growing concerns about their potential effects on human health.
PFAS, or perfluoroalkyl and polyfluoroalkyl substances, are chemicals used in many household products. We have known for years that they can enter our bodies through the food and water we consume. But recently, scientists showed for the first time that some PFAS can be absorbed through the skin and into the bloodstream.
Previously it was thought that the skin act as a barrier against PFAS, which have been linked to a number of regarding health effects. Many everyday items that touch our skin, including makeup and fabrics, can contain these chemicals.
So what do we know about the effects of PFAS on our health?
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How does PFAS enter the body?
PFAS are man-made chemicals that have been used since the 1940s and still are found in many productsincluding non-stick cookware, waterproof clothing, COSMETIC and dental floss. They are primarily valued for being non-sticky; resistant to water, oils and stains; and flame resistant. Sometimes they are added to products to improve their texture or shine.
Current ratings suggest that about 15,000 different PFASs have been invented and more are still being developed.
PFAS take thousands of years to break down and so accumulate in the environment and in the bodies of men and animals. They are found in soil, food, air and drinking water, as well as in the blood of most people in the USA
One of the ways they enter the human bloodstream may be through the skin, recent studies suggest. Published in May in the magazine Environmental Internationalstudy measured the absorption of 17 commonly used PFASs using 3D models made from lab-grown human skin.
“We found that most of the PFAS we included in our study can be absorbed into human skin.” Oddný Ragnarsdóttir, who led the study as part of her PhD at the University of Birmingham in the UK, told Live Science. At this point, however, it is unclear what doses of PFAS people would actually be exposed to through skin contact and how harmful those doses are.
PFAS have also been found in Breast milkand more than 40 studies they found them in cord blood collected at birth. The latest research, published in May in the journal Eco-Environment & Health, showed that PFAS readily travel across the placenta. This supports evidence that many people may be exposed initially in prenatal PFAS.
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What do PFAS do to the body?
Once in the bloodstream, PFAS binds to proteins and can enter cells and organs, where they remain for years or even decades. Scientists are still learning about the health effects of various PFASs, but there is some evidence of their potential harm.
In 2016, the National Toxicology Program published a summary regarding the two most common PFASs: perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). The review mainly looked at experiments in laboratory animals and epidemiological studies in humans, which sought associations between PFAS exposure and population-level health effects.
It concluded that both PFOA and PFOS are potential “immune hazards to humans.” The strongest evidence suggests that both PFOA and PFOS can inhibit antibodies answers. Weaker evidence linked PFOA to a higher risk of autoimmune disease and allergies in humans, while in animals, PFOS suppresses natural killer cells, which normally destroy diseased cells, including cancer.
What’s less clear, the review noted, is exactly that HOW PFOA and PFOS produce these effects.
More recent studies are beginning to reveal this, finding that PFAS can alter the function of various proteins that are or produced by the body or obtained through the diet. Except this, a 2023 revision from the World Health Organization’s International Agency for Research on Cancer (IARC) found “strong mechanistic evidence” linking PFOA and PFOS to epigenetic changes, meaning molecular changes that affect how genes are activated. For PFOA, there was also “sufficient” evidence that the chemical was capable of causing cancer in laboratory animals, while similar evidence was “limited” for PFOS.
As a result, in 2023, IARC Classified PFOA as “carcinogenic to humans” and PFOS as “possibly carcinogenic to humans”. Agency classifications have nothing to do with how much a substance may increase the risk of cancer but how definitively can the IARC say that it causes cancer at all. In this regard, the evidence is stronger for PFOA than for PFOS.
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Studies also suggest that PFAS may affect reproductive health. or 2021 revision found that exposure to PFOA and PFOS were both associated with lower testosterone levels and sperm quality in men, at the population level.
Exposure to PFAS in utero has also been linked to lower antibody responses to childhood vaccines, such as those for diphtheria, rubella AND mumps. This early exposure is also associated with changes in the way teenagers and young adults breaks down fats and proteins; there is concern that this may increase the risk of metabolic diseases.
Beyond PFOA and PFOS, thousands of other PFASs are yet to be studied. “One big thing we don’t know yet is which PFASs are in which products and at what concentration,” he said Stuart Harradprofessor of environmental chemistry at the University of Birmingham and senior author of the recent study on PFAS skin absorption.
“If a well-absorbed PFAS is present in high concentrations in a cosmetic or fabric with which we have prolonged skin contact,” Harrad said, “then the resulting exposure will be substantial and may be equivalent to that we get through diet or drinking water”.
With accurate measurements of the doses people are exposed to through the skin, toxicologists and epidemiologists can begin to assess the health effects of those doses, he said.
What about now?
PFOS and PFOA have been steadily phased out of US manufacturing since the early 2000s. This has resulted in drop in blood levels over the past two decades, but the chemicals persist in the environment and are still used in other countries. In addition, new, less studied PFASs have emerged to replace those two.
“As ‘old’ PFASs have been phased out or banned, ‘new’ ones have been introduced,” it said. Andrew Wattersona public health researcher at the University of Stirling in Scotland.
“The cumulative and total risks to workers who make, apply and are exposed to many PFASs, and to consumers and the public who come into contact with PFASs and the wider environment, have yet to be fully assessed,” he told Live Science in an email. The data gaps that still exist for chemicals that have been used for decades are very concerning.
Federal agencies AND UNITED are making efforts to limit PFAS in water and consumer products. However, removing PFAS from our bodies and the environment will be difficult and costly.
Meanwhile, the Environmental Protection Agency has issued a updated guide how consumers can reduce their exposure to PFAS. He advises people to install water filters at home; to avoid eating fish from contaminated waterways; and to avoid PFAS-treated fabrics and other household products known to contain PFAS.
Consumers may be able to pressure manufacturers to remove or reduce PFAS in their products, Watterson said. But in general, the public can do little to avoid coming into contact with chemicals already present in the environment, he said. Solutions will require regulating all PFAS, he said, and eventually cutting them off at their sources.
This article is for informational purposes only and is not intended to provide medical advice.
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