The BPA Emperor Has No Clothes

Steven Hentges, Ph.DMonday, January 29, 2018 SAFETY
Most likely you’ve never heard of Paracelsus, a Swiss physician from the 14th century, but
you live every day with a toxicology principle that he created. That principle, simply statedas “the dose makes the poison,” has stood the test of time for about 500 years.
For example, if you have a couple of drinks you might get a hangover, but if you drink too
much you could die from alcohol poisoning. A couple of aspirin might help with thehangover, but a whole bottle of aspirin could act as a poison and kill you. In both cases,
it’s the dose that makes the poison, and that principle applies to just about everything we
contact in our daily lives.
In simple terms, the safety of a substance is determined by first testing to establish a doseat which no health effects are observed, and, therefore, the dose is considered to besafe. Consistent with Paracelsus’ principle, if exposed to an even lower dose, no healtheffects would be expected at those lower doses either.
In recent years though, some scientists have questioned whether Paracelsus had itright. In particular, they’ve suggested that very low doses of some substances could causea health effect while the established safe dose of the same substance does not cause thehealth effect.
That counterintuitive relationship between dose and health effect is known scientifically as
a “non-monotonic dose-response” relationship or NMDR. If NMDR is a real phenomenon,
the basic paradigm for determining safe levels of exposure may not be valid for allsubstances.

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A common example of a substance considered by some scientists to exhibit NMDR isBPA. For example, a recent scientific paper referred to “a wealth of prior literature showingthat BPA … can have non-monotonic dose response curves.”
Although it has been frequently stated that BPA and other substances have NMDR, simply
saying it is so doesn’t make it so. In science, solid evidence is required to support thevalidity of a supposition, in particular one as far-reaching as the claims about NMDR.
As indicated by the title of a recent publication in the peer-reviewed scientific literature(Evaluating the evidence for non-monotonic dose-response relationships), the validity of
NMDR has now been tested with scientific evidence. Notably the analysis wascommissioned by the European Food Safety Authority (EFSA) and conducted by a panel ofscientists from four European government agencies and scientific institutes.
The EFSA expert panel first scoured the scientific literature for studies that might include
evidence for NMDR on substances relevant for food safety, which includes BPA. Studies
deemed to be relevant and reliable were then evaluated against six checkpoints specificallydesigned to assess the strength of the evidence for NMDR.
The results of the expert panel evaluation are distinctly at odds with common wisdom about
the validity of NMDR:NMDR as a common phenomenon for substances in the area of food safety was notsubstantiated by the data selected and analyzed in this review.

Overall, the results of this review show that the empirical evidence for NMDR in thescientific literature for substances in the area of food safety is limited or weak.
Of the studies considered to be relevant and reliable and that met the checkpoints for
NMDR, how many provided evidence that BPA displays the so-called NMDR phenomenon?
There were none – no sound and reliable scientific evidence at all to support claims thatBPA exhibits NMDR.
The findings of the expert panel have important implications for the safety of BPA. Basedon scientific evidence, and consistent with Paracelsus’ principle, many government
agencies around the world have concluded that BPA is not a health concern.
2/3As an example, EFSA stated “BPA poses no health risk to consumers of any age group(including unborn children, infants and adolescents) at current exposurelevels.” Considering the findings of the expert panel on NMDR, that conclusion continues
to be valid.

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