In an article published on April 19, 2016 the National Food Institute at the Technical University of Denmark (DTU Food) reports on the results of a laboratory animal study examining the effects bisphenol A (BPA, CAS 80-05-7) on growth, brain development and the reproductive system in rats. Ulla Hass, professor and head of the research group on reproductive toxicology at DTU Food, and colleagues, exposed rats in foetal life and during lactation to low and high doses of BPA. The researchers found that particularly low doses of BPA affect the animals’ development. Female rats exposed to the lowest BPA dose during early life had increased body weight as adults and exhibited behavioral changes in the direction of male behavior. Male rats exposed to the lowest BPA dose had increased growth of mammary gland tissue, and decreased sperm count as adults. These effects were not observed at the higher BPA doses. Further, mammary gland changes possibly indicative of an early stage of breast cancer were observed in aging rats exposed to the second lowest dose of BPA. The study results are published in two articles in the peer-reviewed journal Andrology, reporting on the effects of BPA exposure on mammary gland development and sperm count and behavior, respectively.
Based on their results, Hass and colleagues recommend a tolerable daily intake (TDI) of 0.7 µg/kg body weight/day or lower in order to sufficiently protect humans from the endocrine disrupting effects of BPA. The European Food Safety Authority (EFSA) set the TDI for BPA to 4 µg/kg body weight/day in January 2015 (FPF reported).
The study is particularly noteworthy because it was carried out following Good Laboratory Practice (GLP) standards, a framework for reporting of scientific studies introduced in 1978 following several cases of scientific misconduct in commissioned testing of chemicals for the purpose of risk assessment (Myers et al. 2009). GLP studies are often considered “gold standard” in chemical risk assessment. In the present study, Hass and colleagues reproduce low dose effects of BPA exposure during early life from earlier non-GLP studies. As such, the present study may assist risk assessors in evaluating BPA’s low dose effects.
The study by Hass et al. is however not considered helpful by all. In a commentary article published on April 22, 2016 by the American Council on Science and Health (ACSH), journalist Josh Bloom calls DTU Food’s study “laughably-flawed” and claims that “there are small differences between the controls and BPA-treated rats, and a less-than-convincing pattern or trend” regarding the BPA-effects reported by the DTU researchers.
DTU Food (April 19, 2016). “Bisphenol A in low doses can affect the reproductive system and behavior.”
Science Daily (April 19, 2016). “Bisphenol A in low doses can affect the reproductive system, behavior.”
Josh Bloom (April 22, 2016). “A study is rotten in the state of Denmark, and here’s why.” American Council on Science and Health
Philip Lightowlers (May 4, 2016). “Danish institute says study confirms BPA low-dose effects.” Chemical Watch
Mandrup, K. et al. (2016). “Low-dose effects of bisphenol A on mammary gland development in rats.” Andrology (published online April 18, 2016).
Hass, U. et al (2016). “Low-dose effect of developmental bisphenol A exposure on sperm count and behaviour in rats.” Andrology (published April 18, 2016).
Myers, J.P. et al. (2009). “Why public health agencies cannot depend on Good Laboratory Practices as a criterion for selecting data: The case of bisphenol A.” Environmental Health Perspectives 117(3):309-315.