Recently a friend asked me how worried she should be about Bisphenol A, also known as BPA, which is a component of some plastics. “Well……” was my answer. “Quite worried,” I was thinking, but I didn’t want to add “and there are a whole host of other related issues too.”
I should say that this is a complex issue that I won’t pretend to portray as simple. I’m not out to incriminate anyone – I merely want to help readers understand what BPA is and the potential health effects on the human body, and clarify the status of research on BPA in a non-inflammatory, balanced way. In another post (in a week’s time) I’ll discuss what you can do to avoid it if you decide that’s the right path for you.
What is BPA and why is it in my plastic?
BPA is the building block for epoxy resins (think: coatings, like in the lining of food and drink cans) and polycarbonate plastic (think: the old Nalgene water bottles). It’s also used as an antioxidant in PVC and as a developing agent in the coating of thermal paper (so fast-printing register receipts are covered in it). BPA makes the plastic strong and transparent, and prevents the can from corroding (that’s why it’s often used to line cans holding tomatoes, which are acidic).
2. How does BPA get into the human body?
“The primary source of exposure to BPA for most people is through the diet. While air, dust, and water are other possible sources of exposure, BPA in food and beverages accounts for the majority of daily human exposure.
Bisphenol A can leach into food from the protective internal epoxy resin coatings of canned foods and from consumer products such as polycarbonate tableware, food storage containers, water bottles, and baby bottles. The degree to which BPA leaches from polycarbonate bottles into liquid may depend more on the temperature of the liquid or bottle, than the age of the container. BPA can also be found in breast milk [because it is found in the mother’s diet].” Source: NIEHS
3. What is the endocrine system?
“The human endocrine system is composed of a complex network of glands that release hormones into the blood to signal and govern normal growth, development, metabolism and reproduction. Human hormones include estrogen, progesterone, testosterone, thyroid hormones, and melatonin, among others, and these can be biologically active at exceptionally small doses.” Source: Wargo et al. 2008
4. How does BPA affect the endocrine system?
Paracelsus’ Dictum says that ‘the dose makes the poison’ – and in the case of many chemicals, a higher dose = more poisonous. Not so with BPA, because hormones work differently on the endocrine system:
Hormones are produced in accordance with a finely tuned feedback system that’s regulated by a pair of command and control glands in the brain, the pituitary and the hypothalamus. If the levels of hormone get too high or too low, the hypothalamus relays that information to the pituitary, which in turn signals the gland that produces that hormone to gear up or slow down. Because of that feedback loop, “sex hormones cause opposite effects at high and low doses. At high doses, they turn off responses that they stimulate at low doses.” Freckel (quoting vom Saal), 2011, p.94
The FDA set its ‘reference dose’ for BPA based on some high-dose studies conducted by the U.S. National Toxicology program in 1982. The FDA then divided that dose by 1,000 to set the maximum daily dose it believed would be health-protective – normally a very safe buffer, as long as the effects on human health at low doses had been studied – which they had not. Source: Wargo et al. 2008
5. What is an endocrine disruptor and what does it do?
“Endocrine disruptors are chemicals that may interfere with the body’s endocrine system and produce adverse developmental, reproductive, neurological, and immune effects in both humans and wildlife. A wide range of substances, both natural and man-made, are thought to cause endocrine disruption, including pharmaceuticals, dioxin and dioxin-like compounds, polychlorinated biphenyls, DDT and other pesticides, and plasticizers such as bisphenol A…The National Institute of Environmental Health Sciences supports studies to determine whether exposure to endocrine disruptors may result in human health effects including lowered fertility and an increased incidence of endometriosis and some cancers. Research shows that endocrine disruptors may pose the greatest risk during prenatal and early postnatal development when organ and neural systems are forming.” Source: NIEHS
6. Do scientists think that BPA is safe?
As Douglas Main, writer over at Newsweek, succinctly put it in 2015: “BPA is fine, if you ignore most studies about it.”
In other words, it depends who you ask. Studies underwritten by the chemicals industry generally find it to be safe, while government-funded studies generally find correlations (although not cause and effect) between BPA and endocrine disruption.
11 out of 11 studies funded by the chemical industry have found that BPA has no significant health effects in humans. 109 out of 119 studies that were not funded by the BPA/chemicals industry found that BPA has an effect on human health. Source: vom Saal and Welshons 2006
‘Dr. Csaba Leranth, a Yale School of Medicine physician and scientist whose studies have shown that BPA reduces the number of synapses (brain cell connections) in monkey brains, is more direct: “Studies funded by industry are not reliable.”’ Source: Main 2015
One government-funded study which found that BPA is safe was largely ghost-written by representatives of the plastics industry. Source: Rust, Spivak & Kissinger 2008
7. Doesn’t the Food & Drug Administration (FDA) say that BPA is safe?
Yes. “FDA’s current perspective, based on its most recent safety assessment, is that BPA is safe at the current levels occurring in foods. Based on FDA’s ongoing safety review of scientific evidence, the available information continues to support the safety of BPA for the currently approved uses in food containers and packaging.” Source: FDA
Before developing its opinion, the FDA reviewed many available studies on the effects of BPA on human health. In some cases, the FDA’s opinion of the quality of a study is in direct contrast with that of the National Toxicology Program:
For example, one study funded by the National Institutes of Health and the Department of Defense looked at the effects of bisphenol A on prostate development in rats.
The FDA called it “severely limited,” in contrast to the NTP’s review, which labeled it of “high utility.”
Another government-funded study, which also looked at the effects of the chemical on the prostate, again was considered of “high utility” by the NTP for its evaluation, and it was deemed “very limited” by the FDA.
Much of the science that the task force considered was 20 years old or older, including a study commissioned in 1976.
The older studies are not as sensitive as modern tests. They used high doses of the chemical and did not consider the unique effects on the endocrine system. Source: Rust, Spivak & Kissinger 2008
Safe Until Proven Otherwise
By law, U.S. government agencies must treat chemicals as safe until proven otherwise, which puts an almost insurmountable burden of proof on regulators before a suspect chemical can be pulled off the market. The 1976 Toxic Substance and Control Act supposedly gives the Environmental Protection Agency the power to require testing of and ability to restrict toxic chemicals. But:
The sixty-two thousand chemicals in use when the law was passed were exempted from the texting requirements…While twenty thousand chemicals have been introduced since 1976, the EPA has been able to require extensive reviews for only two hundred, and it has used its authority to restrict only five. The hurdles are so high, the agency could not even successfully ban asbestos, an undisputed carcinogen. Source: Freinkel 2011 p. 106
American consumers might look to Europe to see what regulations are in force there when purchasing products.
The European Union’s 2007 REACH (“Registration, Evaluation, Authorization and Restriction of Chemicals”) law puts the burden of proof on companies to show that their products are safe for use, and communicate risks to users:
“To comply with the regulation, companies must identify and manage the risks linked to the substances they manufacture and market in the EU. They have to demonstrate to ECHA how the substance can be safely used, and they must communicate the risk management measures to the users.
If the risks cannot be managed, authorities can restrict the use of substances in different ways. In the long run, the most hazardous substances should be substituted with less dangerous ones.” Source: European Chemicals Agency
REACH legislation, as well as the laws of many other countries, use the precautionary principle as a foundational tenet:
“When an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically. In this context the proponent of an activity, rather than the public, should bear the burden of proof. Source: Science & Environmental Health Network
This is why many chemicals are available for regular use and consumption in the U.S. but are restricted or banned in the E.U, including:
- Red Dye no. 40, Yellow Dyes no. 5 and 6
- U.K.: Banned due to health concerns
- Rest of E.U.: Products must carry labels warning of the dyes’ potential adverse effect on attention and behavior
- U.S.: Unrestricted use
- Atrazine, possibly the most heavily used pesticide in the U.S., and found in 94% of U.S. drinking water tested by the USDA
- E.U.: Banned in 2003 due to concerns about its ubuquity as a water pollutant
- U.S.: Unrestricted use
- Formaldehyde and formaldehyde-releasing chemicals in cosmetics and personal care products
- Sweden & Japan: Banned
- E.U.: Levels are limited
- State of Minnesota: Banned in-state sales of childrens’ personal care products containing these chemicals
- Rest of the U.S.: Unrestricted use
- Lead-based paint
- Belgium, France & Austria: banned in 1909
- Most of Europe: banned before the 1940s
- U.S.: banned in 1978, “even though health experts had, for decades, recognized the potentially acute — even deadly — and irreversible hazards of lead exposure.” (Source for information on the legal status of chemicals: Grossman 2014)
Don’t expect U.S. government agencies to track the safety of emergent threats and keep consumers safe in a timely manner via warnings or legislation. It just won’t happen.
Because U.S. law takes the opposite approach to one grounded in the Precautionary Principle, U.S. consumers find themselves playing a game of Whac-A-Mole: BPA was an important component of polycarbonate plastics, and had to be replaced with something; most commonly Bisphenol F and Bisphenol S. These chemicals are structurally very similar to BPA, and a 2015 review of studies found that “BPS and BPF are as hormonally active as BPA, and have endocrine disrupting effects” (Source: Rochester & Bolden 2015 p.2). So a “BPA free!” label does not mean “This product is safe!”
We shouldn’t focus our energy on banning BPA (and BPS and BPF) because we will never win: there will always be a replacement chemical needed that most likely has not been adequately tested for safety. Instead we should require manufacturers to show that their products are safe.
OK, so what do I do about it?
Good question. Soon I’ll discuss ways you can avoid BPA (which basically comes down to avoiding certain plastics), and also address a personal conundrum: there are many instances in which making an attempt to avoid chemicals like BPA results in a higher overall environmental impact – requiring the consideration of some very difficult trade-offs.
Update: The second in this two-part series is now here.