These two Danish studies, recently published in the journal Andrology, help fill a gap in the literature used in regulatory risk assessments of the safety of Bisphenol A (BPA). The researchers complied with the practices and procedures required by “Good Laboratory Practices” or “GLP.” These are the criteria that regulatory bodies like the FDA and Europe’s EFSA (European Food Safety Authority) require for laboratory studies to be considered in regulatory risk assessment – and the reason why hundreds of academic/university studies that show evidence of concern over low dose exposure to BPA have been dismissed by the FDA in its official safety assessments of BPA. GLP requirements focus on documentation rather than quality of science, so many innovative, well-designed and conducted studies are left out of regulatory decision-making.
What did they do in these studies?
The two Danish studies[i],[ii] focus on the effect of a range of doses of BPA on rats whose mothers’ were fed BPA while pregnant and until they weaned their pups. Their offspring (who were never fed BPA directly) were examined for a variety of health effects.
What effects did the researchers find?
- They found that BPA exposures during development (both gestation and via lactation) can have a range of effects including on sperm count in males, body weight, sweet preference, spatial learning ability and both male and female mammary gland development.
- They found that these effects were different in male and female offspring:
- Males exhibited decreased sperm count
- Female body weight was increased at 9-14 months of age
- The spatial learning of females was masculinized (they behaved more like males). There were no clear effects on male behavior
All of these effects were found after exposure to the lowest dose of BPA but not at higher doses.
- They found that some effects are seen at low doses of BPA but not at higher doses. Scientists refer to this as a “non-monotonic dose response.” Patterns like this are are common for hormones and endocrine disrupting chemicals, which disrupt the body’s hormonal systems. These papers give further evidence that these nonmonotonic dose responses are a typical feature of BPA studies and should be considered in safety testing and regulation of this and other endocrine disrupting chemicals.
- They found changes in mammary gland development, which is an important indicator for concerns about breast cancer in humans. Relevant results include:
- Increased mammary development on pup day 22 among males, when exposed to the lowest dose but not the higher doses of BPA;
- Development of intraductal hyperplasia in the mammary glands of female pups when exposed to the second lowest dose but not to lower or higher doses. The study authors comment that this could be associated with an increased risk for developing hyperplastic lesions, which are parallels to early signs of breast neoplasia in women;
- In general, the findings indicate that BPA may contribute to precocious breast development and increase the risk for breast cancer in individuals exposed to BPA during prenatal development and soon after birth.
What does this mean?
In the same issue of Andrology, two preeminent U.S. BPA researchers—Laura Vandenberg and Gail Prins—have written an editorial highlighting the importance of these new studies and why and how they should change the regulation of BPA around the world[iii]. As they say in their editorial:
“These studies clearly ‘tip the scales’ and indicate a need for new regulations, including the setting of new reference doses (in the USA) and tolerable daily intake doses (in Europe). Furthermore, these studies reiterate what has been known in the scientific community for many years: that low doses of BPA can significantly alter a range of hormone sensitive endpoints…. While regulators around the world have been slow to act, scientific communities have taken a stand against EDCs like BPA. And consumers have similarly acted, calling for BPA-free products. Unfortunately, many of these products include other bisphenols, which are poorly studied but have been sufficiently examined to raise concern about their endocrine disrupting properties. We sincerely hope that this movement toward BPA replacements will not lead to another 20 years of regulatory inaction while the public continues to be exposed.”
We at the Breast Cancer Fund continue to call for safety testing of chemicals to be brought into the modern age and include examination of endocrine effects, the inclusion of low doses in testing regimens and the acknowledgement that nonmonotonic dose responses (where lower doses do not always have lower effects) can occur.
What Needs to Happen?
The Breast Cancer Fund continues to call on the federal agencies, including the FDA, EPA and Consumer Product Safety Commission, tasked with protecting the public from toxic exposures to incorporate these established scientific concepts when reviewing scientific studies and/or requiring safety substantiations of emerging chemicals of concern . Relying on old assumptions and science has resulted in dangerous chemicals being used in multitudes of consumer products, including BPA in canned food linings and phthalates, another class of endocrine disrupting chemicals, in children’s toys and cosmetics.
Congress should reform how chemical safety decisions are made and provide the federal agencies responsible for regulating chemicals with the authority to truly protect Americans from unsafe chemical exposures. In the meantime, these new studies demonstrate the need for the FDA to act immediately to revise their BPA safety assessment and ban the use of BPA in all food packaging.
And while we push the federal government to act responsibly, we are also encouraging consumers to demand safer products from manufactures, such as pressuring canned food companies to remove BPA from canned food linings and be transparent about the safety of the chemical replacements they are using. Consumers should join us in calling on Campbell’s, one of the world’s most iconic food brands, and Kroger, a major supermarket chain to adopt clear timelines and benchmarks for moving away from BPA and toward transparently, safer alternatives in the canned foods they make and sell. Be a part of the solution and learn more at www.toxicfoodcans.org.
[i] Hass U, Christiansen S, Boberg J, RasmussenMG, Mandrup K & Axelstad M(2016) Low-dose effect of developmental bisphenol-A exposure on spermcount and behaviour in rats. Andrology DOI: 10.1111/andr.12176. Available at: http://onlinelibrary.wiley.com/doi/10.1111/andr.12176/epdf
[ii] Mandrup K, Boberg J, Krag Isling L, Christiansen S & Hass U (2016) Lowdose effects of bisphenol A on mammary gland development in rats. Andrology DOI: 10.1111/andr.12193. Available at: http://onlinelibrary.wiley.com/doi/10.1111/andr.12193/epdf
[iii] Vandenberg LN & Prins GS (2016) Clarity in the face of confusion: new studies tip the scales on bisphenol A (BPA). Andrology doi: 10.1111/andr.12219 Available at: http://onlinelibrary.wiley.com/doi/10.1111/andr.12219/epdf