Most people reading this are aware of the risks of bisphenol A, also known as BPA. This chemical is commonly found in plastic bottles, but it’s also found in other materials as well, including thermal paper receipts. While many people minimize their exposure to BPA by using BPA-free products, some don’t realize that “BPA-free” doesn’t equal “xenoestrogen-free”. In fact, bisphenol S and bisphenol F are found in BPA-free products, and might be even worse than BPA, which I’ll discuss in this blog post.
But I’d like to start off by talking about bisphenol A. Bisphenol A (BPA) is a chemical commonly found in plastic water bottles, but there are many other sources as well, including food packaging, dental materials, healthcare equipment, thermal paper (i.e. receipts), as well as toys and articles for children and infants (1). Due to its phenolic structure BPA has been shown to interact with estrogen receptors, and thus can play a role in the pathogenesis of numerous endocrine conditions, including male and female infertility, hormone dependent tumors (i.e. breast and prostate cancer), polycystic ovarian syndrome (PCOS), and other metabolic conditions (1). This is why it is labeled as being an “endocrine-disrupting chemical”.
In addition to interacting with estrogen receptors, numerous studies show that BPA can also have a negative effect on thyroid health. One study showed that BPA may alter thyroid function, leading to thyroid abnormalities, including subclinical hypothyroidism and perhaps even thyroid nodules (2). Another study showed evidence that BPA exerts a direct effect on the thyroid follicular cell (3). Yet another study showed that BPA might penetrate the placental barrier and therefore affect the endocrine system of the fetus (4).
Structural Analogs To BPA
A structural analog is a compound that has a similar structure to another compound, with a slight difference. However, it’s important to understand that even though structural analogs might be chemically similar, they can have different physical and biochemical properties. There are numerous structural analogs to BPA, including bisphenol B (BPB), bisphenol E (BPE), bisphenol F (BPF), and bisphenol S (BPS) (5).
The reason why I’m bringing this up is because many people realize that there are risks associated with BPA, and as a result they use BPA-free products. For example, many people drink out of BPA-free plastic bottles, thinking that this is a safer option than drinking out of “regular” plastic bottles. However, studies show that these structural analogs (BPB, BPE, BPF, etc.) have the same effects on the estrogen receptor and androgen receptor as BPA, and most of the alternatives are just as potent as BPA (5).
Admittedly there isn’t as much research on these structural analogs as there is on BPA, and I wasn’t able to find any studies showing a direct negative effect on thyroid health. But the evidence that is available shows that these other compounds are endocrine disruptors like BPA, and I’m sure in the future there will be many more studies which show that it’s best to avoid products that include these chemicals.
What Can You Do To Minimize Your Exposure To These Chemicals?
So what can you do in order to avoid exposure not only to BPA, but to the structural analogs? Well, in this day and age complete avoidance is very difficult, but here are a few suggestions to minimize your exposure:
1. Try not to drink out of plastic water bottles on a regular basis. Obviously it would be best not to drink out of plastic bottles at all, but I realize that sometimes it might be difficult to avoid doing this. For example, if you visit a different country with a questionable water supply, then I’d rather be exposed to the BPA in water bottles than to risk getting sick from drinking the water.
2. Minimize the use of other plastics. For example, plastic wrap usually contains BPA, and perhaps some of the structural analogs. Plastic food storage containers are usually another source, and you even want to minimize the use of plastic utensils. Once again, I realize that completely avoiding all sources of plastic is probably not going to happen, but you want to do everything you can to minimize your exposure to these.
3. Don’t ask for a receipt every time you make a purchase. Numerous studies show that thermal paper receipts (i.e. cash register receipts) can contain high levels of BPA (6) (7) (8). Other sources may use thermal paper with BPA as well, including movie tickets.
4. Be aware of other “hidden” sources of BPA. Other sources of BPA you might not be aware of include some canned foods, dental sealants (9), soda cans, and toilet paper.
In summary, bisphenol A (BPA) is a chemical commonly found in plastic bottles, as well as other materials, including thermal receipts. BPA is labeled as an “endocrine-disrupting chemical”, and some studies show that it can also have a negative effect on thyroid health. Although many people use BPA-free products, most of these people aren’t aware that these products might have chemicals that are similar in structure to BPA, such as bisphenol B, bisphenol E, bisphenol F, and bisphenol S. So you want to try your best to minimize your exposure to BPA by not drinking out of plastic water bottles, minimizing the use of other plastics, not asking for a thermal paper receipt, and by being aware of other hidden sources of BPA.