Disturbing results from a new study reveal that even low, so-called ‘safe’ levels of exposure to the endocrine-disrupting chemical BPA can adversely affect the prenatal brain. As there have now been hundreds of replication studies around the globe demonstrating the potential hazards of BPA exposure, pregnant women and those who plan to become pregnant should take heed and avoid exposure to bisphenol-A. This includes among other things, avoiding canned foods unless cans are specifically marked “BPA-Free’ (consuming only fresh, whole foods or frozen fruits and vegetables is best), working with your dentist to assure BPA-based fillings are replaced, minimizing handling of commercial cleaning products, and avoiding handling cash register and ATM receipts as some continue to contain a BPA-based coating.
Prenatal exposure to BPA at low levels can affect gene expression in developing rat brain
New research from North Carolina State University reveals that prenatal exposure to bisphenol A (BPA) at levels below those currently considered safe for humans affects gene expression related to sexual differentiation and neurodevelopment in the developing rat brain.
BPA is a chemical used in a variety of consumer and household products including some food containers. Experimental data has also suggested a link between the chemical and mood or anxiety-related behaviors in children…
Researchers conducted a study exposing gestating rats to levels of BPA both above and below those currently considered to have no adverse effect — including levels as low as 2.5 and 25 micrograms per kilogram of body weight per day — and looked at effects in the brains of their newborn pups.
The scientists found that prenatal BPA exposure, even at the lowest levels, changed the expression of numerous hormone receptors including those for androgen, estrogen, oxytocin and vasopressin in the newborns’ amygdala, a brain structure involved in a wide range of stress and emotional behaviors. Oxytocin, for example, is important for affiliation and pair-bonding, while vasopressin is involved in stress responses. The changes varied depending upon the sex of the newborn and the amount of exposure. Significantly, disruption of genes critical for synaptic transmission and neurodevelopment were also found to be altered, with females appearing to be more sensitive than males.
“Uniquely, we found that low level prenatal BPA exposure can change androgen receptor expression levels in the amygdala. In humans, this gene is important for forming differences between male and female brains, which suggests this could be a way by which BPA exposure might alter sex differences in the human brain.” -Sheryl Arambula, Ph.D. candidate, researcher
Ongoing scientific research on BPA
Dr Heather Patisaul, co-researcher in the study, is among a consortium of researchers involved in a multi-year, multi-disciplinary project called CLARITY-BPA, a research initiative that includes the FDA, the National Toxicology Program, the National Institute of Environmental Health Sciences (NIEHS), and 13 academic labs. CLARITY-BPA seeks to understand how BPA affects multiple organ systems. Patisaul’s focus is on brain and behavior. All rats in the study were housed at the National Center for Toxicological Research and followed FDA protocols for exposure. CLARITY-BPA experiments were specifically conceived and conducted to provide the FDA with data it could use to make decisions about human health risks.
BPA can adversely affect the developing brain
“In our previous work, including work for this consortium, we found similar changes in other brain regions including the hypothalamus and hippocampus. There is now a wealth of data showing that BPA can alter neurodevelopment. There is no question that prenatal BPA exposure at levels currently considered safe for humans affects hormone-sensitive gene expression in the developing rodent brain, suggesting that what we consider ‘safe’ for human brains may need to be re-evaluated.” -Dr. Heather Patisaul, BPA researcher
Journal Reference: Sheryl E. Arambula, Dereje Jima, Heather B. Patisaul. Prenatal bisphenol A (BPA) exposure alters the transcriptome of the neonate rat amygdala in a sex-specific manner: a CLARITY-BPA consortium study. NeuroToxicology, 2017; DOI: 10.1016/j.neuro.2017.10.005