What BPA can do to our bodies—and how to limit your exposure
The chemical used to make plastics is more prevalent than ever.
You won’t find BPA on labels. It’s undetectable without chemical testing. And it’s nearly impossible to avoid.
Bisphenyl A (BPA) is used to make plastics and can come into our bodies through ingestion, inhalation, or touch. Though research shows BPA is mostly broken down and disposed of by our bodies in a matter of hours, it can potentially be harmful, especially over years of exposure.
Identified as an endocrine disruptor, BPA has been linked to breast and ovarian cancer, as well as immune, thyroid, and metabolic issues.
The Center for Environmental Health (CEH), an environmental watchdog group based in California, recently found what they say is harmful amounts of BPA in hundreds of brands of socks, leggings, sports bras, and shorts. It makes sense, as most of our fabrics now (including polyester, acrylic, and nylon) are made of plastic.
Clothing companies rebuked CEH’s study, one saying their claims “have no merit.” These companies have a lot of support: the chemical industry and other manufacturers continue to assert that BPA is safe, a stance echoed by the FDA. The American Chemistry Council writes that “BPA has little potential to cause health effects, even when people are exposed to BPA throughout their lives.”
In the modern alphabet soup of toxins and pollutants such as PFAS, PCBs, and PBDEs, it’s easy to forget about those compounds that aren’t in the headlines. Despite the surge in awareness around BPA and endocrine disruptors 15 years ago, the problem remains, says Joyce Ohm, a cancer and epigenetics researcher at Roswell Park Cancer Institute in Buffalo, New York.
“It is still a challenge [to] avoid [BPA] in our normal, daily existence,” Ohm says. “You cannot avoid plastics. It’s impossible.”
What does BPA do to our bodies?
Although BPA was first identified in 1891, it only became popular when the burgeoning plastics industry found that BPA could make certain types of plastics, epoxies, and resins harder and more durable. By the 2000s, BPA could be found in everything from water bottles to dental cements to grocery store food labels. The 2003-2004 National Health and Nutrition Examination Survey (NHANES III), conducted by the Centers for Disease Control and Prevention (CDC), found measurable levels of BPA in 93 percent of the 2,517 urine samples it collected from Americans six years and older.
Researchers believe that most of the BPA that ends up in our bodies comes through food, when BPA leaches out of packaging and plastic storage containers. Much of the BPA in our bodies is metabolized by the liver and exits through urine. Most studies indicate that BPA is broken down quickly, usually in a matter of hours.
While BPA is in the body, however, it acts as an endocrine disruptor, altering the delicate molecular choreography we use to send signals via hormones and other chemicals.
Ohm believes that BPA may be more likely to cause harm during fetal development and puberty, due to the large numbers of genes being switched on and off in response to the chemical. Research on humans is limited due to ethical concerns.
BPA causes problems due to its molecular similarity to various estrogens. In the 1930s, research in rats showed that BPA could stimulate the female reproductive system like the sex hormone estrone. Later work showed that BPA binds to estrogen receptors on cells, and it can both amplify the effects of estrogen and block the action of this hormone by not allowing it to bind to receptors. It shows similar divergent effects when it binds to receptors for thyroid hormones, giving BPA the ability to either increase or reduce the effects of these hormones. Scientists are still working to figure out which of BPA’s effects comes through its effects on estrogen and which are caused via other pathways.
Small amounts of BPA can also get absorbed by the skin. Although BPA is found in thermal paper frequently used as store receipts, most people aren’t in contact with the paper often enough and for long enough for it to be considered a major contributor to someone’s overall BPA burden, says Heather Patisaul, a developmental neuroendocrinologist at North Carolina State University.
BPA faces few restrictions
Despite thousands of studies showing “overwhelming evidence of harm” from BPA, the U.S. Food and Drug Administration's regulations on BPA are limited to infant products (baby bottles, sippy cups, and infant formula packaging). And, according to the FDA, BPA has been authorized for food contact use by the agency for more than 60 years.
The European Food Safety Authority banned BPA in plastic bottles and food for babies and children under age 3 in September 2018, and lowered the tolerable daily intake of BPA to 20,000 times less than previous levels in April 2023. Nonetheless, more BPA is made now (an estimated 7,023.87 kilotons in 2022, according to Mordor Intelligence) than ever before, Patisaul says, and U.S. government officials are in the dark as to how it’s used.
“Regulators don't even know where all of this stuff gets used,” says Patisaul.
Part of the challenge of determining harm from BPA and other chemicals has to do with how scientists have historically measured harm. Initially, scientists were concerned with severe illnesses that occurred shortly after a chemical exposure, or conditions that are rarely seen without a chemical exposure, such as mesothelioma and asbestos.
But BPA and other endocrine disruptors can act over years, even decades. What’s more, they seem to increase the risk of many common conditions that have a multitude of causes, making it hard to determine BPA’s impact on health.
The lack of rules on the subject of BPA and other chemicals means that manufacturers don’t have to disclose the chemicals that are used to make everyday items. Since so many of our everyday items are now made with plastic, BPA can be anywhere, including clothing.
“It might seem really odd, but most of our clothing now is plastic. Anything made out of polyester is a synthetic material and all of those synthetic materials are basically plastic,” Patisaul says.
While clothing must contain labels that disclose the types of fibers used in the fabric, clothing makers don’t have to share the chemicals used to make the fibers or treat the resulting fabric. It’s why CEH had no way of knowing if many popular clothing items contained BPA until they began testing.
What you can do to limit exposure to BPA
The ubiquity of BPA means it’s almost impossible to avoid it completely. Still, to reduce your exposure to BPA, you can try the following:
- Avoid plastics. Ohm ditched her plastic water bottle and travel mug for glass and unlined metal alternatives, neither of which contain BPA.
- Check the number stamped onto your plastic product. If it’s 1 (polyethylene), 2 (high-density polyethylene) or 5 (polypropylene), the product was not made with BPA.
- Don’t microwave food in plastic containers. Plastic food storage containers are cheap, convenient, and hard to avoid. If you do opt for plastic, Ohm recommends reheating the contents on a plate, which will help reduce how much BPA leeches into the food.
- Change your exercise clothes ASAP. Especially when working out in warm weather, polyester/Spandex blend shirts, shorts, and other items can be a necessity. Leiva recommends changing out of your sweaty workout gear as quickly as possible to minimize how long it’s in contact with your skin.
- The grandma rule. Ohm asks herself: was this material around when my grandmother was growing up? If not (think plastics), then she tries to find something less likely to be contaminated.
