Updated: Mar 22
Ever wondered if there is a link between Bisphenol A (BPA) and breast cancer? Is BPA to blame for some types of breast cancer and other cancers?
BPA is used to make polycarbonate plastics found in many plastic products which directly affect our food, such as food storage containers and plastic water bottles. Since the 1930's, we've known that the chemical may impact the human hormone estrogen.
This means BPA is an endocrine disruptor, as it has the ability to alter hormone activity. When absorbed in the body, this kind of endocrine disruptor mimics the body's natural hormones. Estrogen is directly linked to hormone-sensitive cancers, especially breast and ovarian cancer.
BPA is ubiquitous in the environment
Indeed, the The National Institute of Environmental Health Sciences (NIEHS) considers BPA an endocrine disruptor, and the Endocrine Society in its own research on hormones, includes BPA in its Guide for Public Interest Organizations and Policy Makers on Endocrine Disrupting Chemicals & Plastics.
What the research says about BPA and breast cancer
In 2021, in a unique collaboration between FDA and university scientists, a compendium of findings were released from the Consortium Linking Academic and Regulatory Insights on the Toxicity of Bisphenol A (CLARITY-BPA).
Here's what they found in their studies on rats, for example.
Breast glands — Any changes observed were deemed insignificant because, while low doses showed changes, higher doses did not. Scientists determined that this effect was not caused by BPA.
Prostate Cancer - Following a later-life estrogen exposure simulating the aging human male, BPA did increase cancer, with the greatest effects observed at a per-day dose of 2.5 micrograms BPA per kilogram body weight. In addition, when exposed to low doses of BPA or ethinylestradiol, a synthetic estrogen, the developing male prostate and urethra showed a smaller urethra.
Brain and behavior — While no changes in brain tissue were observed in rats, they did observe changes in the expression of estrogen and androgen receptors, the expression of genes involved in sexual differentiation and neuroendocrine function, and limited sex-specific effects on learning and memory, among other findings.
Ovarian Cancer — BPA exposure at some doses alters follicle numbers and sex steroid levels in female rats.
Scientists urged researchers to continue their work with new tools and metrics. However, and this is critical, the researchers called the report "illuminating," and it is far from the last word on BPA. They were concerned that studies may not have identified all potential hazards, particularly hormone-disrupting substances like BPA.
Water bottles may contain BPA
What's being done about BPA and breast cancer?
The US, along with Japan and Europe, allows BPA for food contact use with certain limitations.
The US continues to study the BPA chemical and its link to breast and other cancers. It no longer allows the use of polycarbonate (PC) resins in infant feeding bottles (baby bottles) and spill-proof cups, including closures and lids in sippy cups, and epoxy resins as coatings in packaging for infant formula in response to a petition filed by the American Chemistry Council. The FDA qualified this action was not done because BPA causes harm; rather, it wasn't necessary to be included in these items.
In its most recent report, the European Food Safety Authority claimed exposure to BPA in diet and environment to be 3 to 5 times lower than the tolerable daily intake, and remains below a safe level. But it also eliminated BPA in feeding bottles — while concluding it's well below safe levels — because of concerns that potential toxicological effects may have a stronger impact on the developing organism.
Given that research is still continuing and that breast cancer is more sensitive to diet and environmental chemical exposures, those at high risk or survivors of breast and ovarian cancer, may choose to avoid BPA as much as possible, without being overly concerned.
How to avoid BPA for breast cancer
Is it possible to avoid BPA in our diet and environment? The National Health and Nutrition Examination Survey has found that almost all Americans have BPA in their urine. Most of us are exposed daily to BPA through food and drinks. Air, dust, and water also account for other possible sources.
Bisphenol A leaches into food from the epoxy resin coatings inside of canned foods and from polycarbonate tableware, food storage containers, water bottles, baby bottles, and even water pipes. BPA leaches from polycarbonate bottles into the contents at higher temperatures (think of water bottles left in the car). BPA has also been found in breast milk.
Here's how to substitute potentially safer products:
Use stainless steel, glass, or aluminum for water bottles and food storage, particularly for hot food or liquids.
Use alternatives to plastic wrap.
Choose BPA-free canned goods.
Brew coffee in a glass French press instead of a percolator.
Keep plastic out of the dishwasher, freezer, and microwave.
Don't leave plastic food containers with food or beverages in a hot car.
Don't rely on recycle codes on the bottom of plastic containers. Some plastics that are marked with recycle codes 3 or 7 may be made with BPA.
Use baby bottles that are BPA free.
Conclusion about BPA and breast cancer
BPA is an endocrine disruptor and research remains inconclusive about its safety. Still, for anyone concerned about breast cancer, it makes sense to substitute safer products which come into contact with your food.
As a registered dietitian nutritionist who works with people experiencing cancer, I’d love to help. I offer clients support to plan, shop, and prepare more nutritious and healthy meals for yourself or your family. Here is my link to book a chat about making sure to meet your nutritional needs.