Perfluoroalkyl substances (PFAS), also known as “forever chemicals” because of their persistence in the environment and in the human body, are a group of chemicals widely used in various industrial and consumer products. PFAS include a wide range of chemicals, with the most common being perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). They are found in nonstick coatings, firefighting foams, food packaging, water- and grease-resistant fabrics, and many other everyday items. These chemicals are hydrophobic and lipophobic, making them resistant to water and oils. Although useful in many industrial and consumer applications, PFAS are extremely resistant to degradation, accumulating in the environment and in the human body for years. There is growing concern that PFAS can accumulate in the body and environment, potentially affecting human health.
PFAS can be absorbed into the human body through several routes. The first route is through contaminated foods, such as fish, meat, water, and food products packaged with PFAS-treated materials. In some areas, drinking water is a major source of PFAS exposure. Industrial facilities using PFAS can contaminate local water supplies, leading to regular intake through consumption of contaminated water (Post et al., 2012). Foods can be contaminated with PFAS through soil and water, as well as during packaging processes. Among foods, fish are particularly susceptible to PFAS contamination due to bioaccumulation, the ability of chemicals to accumulate in living organisms throughout the food chain. Fish from contaminated waters is often a major dietary source of PFAS for humans (Bhavsar et al., 2014).
Animals that consume contaminated water or feed can also accumulate PFAS in their tissues, which then enter the human food chain through the consumption of meat, milk, and eggs. Some food packaging, such as microwave popcorn bags, fast food containers, and waxed food wrappers, can be treated with PFAS to make them resistant to grease and moisture. These compounds can migrate into foods, contributing to dietary exposure (Schaider et al., 2017). The problem is that while PFAS are “forever” substances in the most technical sense, they are far from inert. Long-term exposure to PFAS has been linked to a variety of adverse human health effects. Although human studies are ongoing, current evidence suggests that PFAS can affect multiple body systems. Some studies have linked exposure to PFAS to an increased risk of obesity and type 2 diabetes.
This may be because PFAS interfere with hormone regulation and mechanisms that control metabolism. Indeed, the scientific community has included PFAS among the substances called external endocrine disruptors (EDCs), which have the power to affect receptors for hormones such as testosterone, estrogen, and thyroid hormones. Exposure to PFAS has been associated with reduced fertility in both men and women, as well as complications during pregnancy, such as preeclampsia and low birth weight (Fei et al., 2007). They can also impair the function of the immune system, reducing the body’s ability to fight infections and respond adequately to vaccinations (Grandjean et al., 2012). Indirectly, this could influence the onset of tumors: animal studies and some epidemiological research suggest that PFAS could increase the risk of some types of cancer, including kidney and liver cancer (Barry et al., 2013).
Being aware of the sources of these substances can go a long way toward avoiding them. In addition to diet, people can be exposed to PFAS through the air or indoor dust, especially in homes with carpets, furniture, or clothing treated with these compounds. Water- and grease-resistant items, such as outdoor clothing, rugs, and nonstick cookware, can release PFAS into the air and into the human body through contact with skin or household dust. Foams used in emergency situations or training exercises contain PFAS and are a significant source of environmental contamination; but this is especially true near airports and military bases. Although PFAS are ubiquitous, there are practical steps one can take to reduce your exposure. For example, if you live in an area with potentially contaminated drinking water, using reverse osmosis filters or PFAS-specific filters can significantly reduce the concentration of these substances in your water.
In terms of diet, consuming fish from uncontaminated sources and preferring fresh, unpackaged foods can help limit PFAS intake. Avoiding foods in packages treated with PFAS-based coatings is another useful strategy. Stainless steel or cast iron cookware should also be preferred over non-stick coatings that may contain PFAS. In the home and for furnishings, avoiding stain-resistant or chemically coated carpets and fabrics is a possible choice. Paying attention to products that are resistant to water or grease and opting for natural or untreated alternatives is also possible and dependent on personal choice. Finally, PFAS are a growing public health concern due to their persistence in the environment and their potential impact on human health. Diet, particularly through consumption of contaminated water, fish, and packaged foods, represents a significant route of exposure.
However, there are practical measures that can be taken to reduce exposure to these toxic chemicals. With increased awareness and stricter regulations, it is hoped that the impact of PFAS on health and the environment will be reduced.
- Edited by Dr. Gianfrancesco Cormaci, PhD, specialist in Clinical Biochemistry.
Scientific references
Cardenas A et al. JAMA Network Open 2019. 2(3):e191932.
Schaider LA et al. Environ Sci Technol Lett 2017; 4(3):105.
Bhavsar SP et al. Environmental Pollution. 2014; 189, 60-69.
Barry V et al. Environ Health Perspect 2013; 21(11-12):1313.
Grandjean P, Andersen E et al. JAMA 2012; 307(4):391-97.
Post GB et al. Environmental Research 2012; 116:93-117.
Fei C, McLaughlin J et al. Human Reprod. 2007; 24(5):1200.