Welcome to Common Ground, a podcast series discussing new research and interesting projects in the field of complementary medicine. Hello, my name is Wendy McLean, educator at vital.ly.
Vital.ly is a digital platform, a professional health resource and a distribution service all in one. We specialise in complementary medicines and distribute high quality products from our base in Mascot, Sydney.
Today, I'm going to be talking about the health impacts of PFAS, a class of manufactured chemicals present in many consumer goods and industrial applications. These chemicals have been linked to hormone disruption and other serious health effects, even at low doses. In this podcast, I will look at the latest research on health impacts, identify methods for assessing PFAS exposure and discuss ways we can reduce exposure, minimise health impacts and support recovery and wellbeing.
Per- and poly-fluoroalkyl substances, also known as PFAS, are a class of synthetic, fluorinated chemicals resistant to heat, water, and oil.
For over 70 years, these chemicals have been used for hundreds of different consumer products and industrial applications, including stain- and water-resistant coatings for clothing, furniture and carpets, (examples are Scotchguard and Gore-Tex), non-stick coatings (Teflon is the best known example) and food packaging, cosmetics, personal care products, and firefighting foams.
There are over 8,000 of these chemicals that are listed with the US EPA and more than 600 of these are currently believed to be in commercial use.
Perfluorooctane sulfonate (PFOS) (found in Scotchguard) and perfluorooctanoic acid (PFOA) (found in Teflon) are the most extensively produced and studied PFAS. They have been phased out of production in USA, however, large-scale production is still occurring in countries such as China, and human exposure remains high worldwide.
So why are we so concerned about these chemicals?
Firstly, they are extremely persistent.
The chemical backbone of PFAS is made of carbon-fluorine bonds, which is the strongest known chemical bond. And as a result, these chemicals are incredibly resistant to environmental degradation, earning them the nickname ‘forever chemicals’.
The second reason is their widespread occurrence.
Decades of high-volume production of PFAS, coupled with the environmental persistence of these chemicals, have led to widespread PFAS contamination of soil, water, air, even in remote areas including Antarctica, and bioaccumulation across entire ecological food chains.
The third reason is that they bioaccumulate in humans.
So once they are ingested through food or water, they are readily absorbed and they can accumulate in the body where they can persist for decades. Global biomonitoring studies have detected these chemicals in nearly a hundred percent of humans studied; with these chemicals detected in blood, the lungs, liver, and breast milk.
The fourth reason is that these chemicals are linked to an array of health issues, some at very low doses.
And lastly, these chemicals are universally detected in the serum of pregnant women, neonates, and children worldwide, indicating that exposure is ubiquitous, and these chemicals can cross the placenta and influence infant development.
So looking now at the health impacts.
The long-term health impacts are not well understood due to the vast number of these chemicals and limited toxicology data. However, a growing body of evidence from population studies has linked some of these chemicals with a variety of adverse health effects.
The most consistent findings from these studies are increased cholesterol and that is both in children and infants and at levels that are clinically relevant.
Some studies have found associations between PFAS exposure and metabolic effects, including insulin resistance, changes in blood sugar levels, and diabetes.
Other effects include elevated liver enzymes, impaired kidney function and increased uric acid levels.
PFAS exposure also has adverse effects on the immune system. Several studies demonstrate an association between prenatal exposure to PFAS and reduced vaccine responses, increased risk of childhood infections and allergies; suggesting that these chemicals cause immunosuppression.
They have also been shown to affect vaccine efficacy and antibody response in adults, including to the flu vaccine. And currently there is concern over PFAS exposure and the efficacy of the COVID-19 vaccines, which are being rolled out. And this is an area that is currently being researched by the US Centre for Disease Control. They are looking at PFAS serum levels in first-line defenders, so people who are exposed to high levels of these chemicals, and their response to the COVID-19 vaccine.
These chemicals are known as endocrine disruptors. They have been linked with thyroid disease and impaired thyroid hormone levels, as well as male and female infertility.
Other reproductive effects, including increased risk of PCOS, delay in onset of menstruation and early menopause (up to two years).
The US EPA has concluded that two of these chemicals, so PFOA and PFOS, are possibly carcinogenic to humans. And there has been an increase in certain types of cancer in areas where there has been exposure to these chemicals. These cancers include prostate kidney and testicular.
There are certain populations that are more vulnerable to the effects of PFAS. One of these groups of fetuses, infants, and children. They have a greater level of exposure, and they are also more vulnerable biologically to the effects of these chemicals than adults. This is because they get early life exposure, these chemicals cross the placenta and then they also are transferred through the breast milk.
Health effects from early life exposure include decreased birth weight, decreased immune responses and hormonal and metabolic effects in later life. And in the mother, PFAS exposure is associated with an increased risk of pregnancy-induced hypertension or preeclampsia and gestational diabetes.
The adverse health effects of these chemicals are related to their unique toxicokinetic properties; that is, the way in which they are absorbed, metabolised and excreted from the body.
These chemicals are readily absorbed after oral consumption, and then they bind to proteins in the blood where they're transported around the body. They are not metabolised or transformed in the body, and they accumulate in the blood serum, kidneys and liver and lungs.
They are primarily eliminated in urine, with smaller amounts in faeces, and in breast milk. However, they bioaccumulate the body because they attach to bile and they continuously recycle from the intestines to the liver in a process that is known as enterohepatic re-circulation. It is believed, partly because of this process, some of these chemicals have very long half lives in the body, which can range from two to nine years, meaning that they can last in the body for decades.
The mechanisms of action by which PFAS may cause these health effects is also not well understood. However, it is known that they do interact with many receptors in the body, including a group of receptors known as peroxisome proliferator-activated receptors or PPARs. Now these receptors regulate things like energy homeostasis, lipid and glucose metabolism, inflammation, and metabolism and function of steroids.
It is also thought that they alter genes which are involved in lipid transport and metabolism, which leads to their hepatic and metabolic adverse effects.
As I mentioned, these chemicals, are endocrine disruptors, so they impair thyroid hormone synthesis and signalling, and disrupt sex hormones as well.
And these chemicals are known to create oxidative stress in the body, as well as impair mitochondrial function and impact glutathione synthesis.
Now there's insufficient evidence to assess whether they directly interact with DNA to cause damage. However, they may have other indirect mechanisms of action, which can induce epigenetic alterations and influence cell proliferation and increase cancer risk.
So how do we assess if someone is suffering from PFAS exposure?
It is very difficult because exposure could have occurred at any point in life. So a thorough case history needs to be taken. And that is right back from the prenatal period, if possible. A detailed family history needs to be taken as well. Parents and grandparents, because it could be the grandparents’ exposure that is having effect on the individual. A detailed dietary record needs to be undertaken as well as environmental and occupational exposures. We need to look at where they lived, where they went to school, their transportation methods, where they work.
Physical examination is important to look for signs of possible exposure. So for example, some of those metabolic and endocrine effects, and also assess biomarkers that could indicate if they've had exposure.
Lab tests are available for some of these PFAS compounds. However, they are not routinely recommended because blood levels are not predictive of health conditions, there is no well-defined normal range and they cannot tell you when an exposure occurred or if it will have a future health impact. These blood tests are the most useful when they are part of a scientific investigation and can be compared to background or community values and where they can be monitored over time.
There may be other biomarkers that may be of more value and in particular, cholesterol and blood lipids, liver enzymes, inflammatory markers, thyroid hormone and function, reproductive hormones, gut function, organic acids, genetic testing.
So what are the broad treatment strategies to treat PFAS exposure?
Minimal research on interventions to accelerate the clearance of these chemicals from our bodies has been undertaken. So therefore reducing exposure is the absolute best and most critical approach to improve health outcomes. And there is data to support this strategy and show that it is effective. There is biomonitoring data from the United States, and it has shown that the average human blood levels of PFOA have declined by more than 60% and PFOS by more than 80% from 1999 to 2014, since they have been phased out of production in the US.
So ways avoid exposure include avoiding Teflon or non-stick cookware, and looking for alternatives like stainless steel or cast on cookware.
Cut back on fast foods. Again these chemicals are present in up to 50% of fast food wrappers, particularly those that are grease resistant. And these PFAS are transferred through to the food.
Avoid stain resistant coatings and choose non-PFAS clothing and sports gear. Now there is a database called PFAS Central, where you can look up and find alternatives that do not contain PFAS for clothing, sports gear, and other consumer goods.
Choose personal care products without flouro in the ingredients. And you will be surprised where these chemicals are found, things like dental floss, nail, Polish, sunscreen, hairspray, other personal care products. And again, there is a database called Skin Deep, which has different makeup and personal care products and their chemical composition. So you can look up and find PFAS free alternatives.
And given that dietary intake is the greatest source of PFAS exposure in most individuals, it is important to track your drinking water source. For example, there are some communities in Australia that are impacted by drinking water sources contaminated by firefighting foams. And in these areas, it is critical to look for an alternative drinking water sources or use a water filter. And there's only certain types of filters that can filter out these chemicals; and these are activated carbon or reverse osmosis.
You also need to check the source of food, especially seafood. Seafood intake has a high correlation with serum PFAS levels.
Because these chemicals create oxidative stress in the body, it is important to address this as well. In terms of reducing oxidative stress, choline, vitamin C and anthocyanin supplementation have been shown to be specifically beneficial in PFAS exposure.
in a double- blind controlled trial, vitamin C was shown to eliminate the effects on insulin resistance and oxidative stress observed in PFAS exposure.
Choline was shown to reduce both oxidative damage and alterations in hepatic lipid metabolism with PFAS exposure.
While there is no direct evidence you could consider other antioxidant nutrients, such as vitamin E, zinc and selenium and herbal antioxidants, including curcumin, green tea, and St. Mary's Thistle. These herbal therapeutics have other activities that could mediate some of these metabolic effects of PFAS exposure. For example, they are anti-inflammatory, they lower cholesterol levels, and can reduce insulin resistance and improve glucose homeostasis. St. Mary's Thistle also protects the liver.
And of course, good nutrition and diet is important for reducing oxidative stress. An anti-inflammatory type diet rich in plant foods and fibre and low in saturated fats is a good approach as it can reduce oxidative stress, replenish the microbiome, facilitate excretion of toxins, and mediate some of those cardiovascular and metabolic effects of PFAS exposure.
Another treatment strategy is to enhance gastrointestinal elimination of these chemicals. Because they are secreted into bile and they are repeatedly reabsorbed and returned to the liver the use of bile acid sequestrants has been suggested. Several studies have demonstrated that one type of bile sequestrant called cholestyramine can increase faecal excretion of PFAS up to 10-fold, with a corresponding reduction in serum and hepatic PFAS levels.
We need to support our microbiome to enhance the elimination of these chemicals and also to mediate the immune and metabolic effects of exposure. Certain PFAS have been found to affect diversity of gut bacteria, inducing notable changes in metabolites widely recognised to be associated with inflammation and metabolic dysfunction. Therefore, we need to support a healthy gut microbiome through good nutrition, such as a fibre-rich diet and the use of pre- and probiotics. And several studies have found fibre rich food intake associated with lower serum levels of PFAS. And this makes sense, given that fibre decreases the absorption of bile acids, and we know that PFAS bind to these bile acids.
A fourth treatment strategy is to support liver detoxification and in particular, the production of glutathione. So supplementing with a glutathione precursor, N-acetylcysteine, could be a treatment option or liposomal glutathione. You could also use herbs that support the synthesis of glutathione, so things like curcumin, Rosemary, Bacopa.
Now this is not an exhaustive list of treatment strategies. It is important to assess the individual and address any other issues such as thyroid dysfunction, metabolic disorders, stress, and reproductive issues.
In summary, PFAS are a class of chemicals that are present in hundreds of different products that are a significant health concern due to their persistence, bioaccumulation and potential toxicity. We don't fully understand their health effects, and we really don't know how we can accelerate the clearance of these chemicals from the body. So reducing exposure is the best and most critical approach to improving our health outcomes.
Thank you very much for tuning into Common Ground today and feel free to subscribe to review this podcast. Thank you.