I was listening to a podcast called “Skeptically Speaking” and an interesting point about industry bias was mentioned regarding bisphenol A (BPA).  You’ve likely heard about BPA when it was widely popular in the media since “Canada was the first country in the world to declare that it intended to label BPA a toxic substance.”  Scientific studies (examples on PubMed and by the Endocrine Society) on this plastic ingredient showed negative human health effects; BPA is an endocrine (hormone) disrupter.

Conversely, independent studies conducted by chemical industries showed results with insignificant BPA effects.  Clever. Worrisome.

Janet Stemwedel, Associate Professor of Philosophy at San Jose State University, and author of the blog Adventures in Ethics and Science identified the following in a Skeptically Speaking interview:

“Every now and then you get the feeling that animal models are chosen intentionally but not correctly.  One of the examples I’ve become aware of recently is in testing of the safety of the chemical Bisphenol A which is often called BPA.  It is a compound used to make polycarbonate plastics and epoxy resins.  There’s been worries about the safety of BPA because it’s similar to the hormone estrogen in its structure.  So if you look at mass media reports on the research on BPA safety; the mass media usually says that there are mixed results, some studies indicate significant impacts on health and others not so much.  But it turns out, if you unmix those studies, 90% of government studies on the safety of BPA have found evidence that BPA has significant health impacts.

Of the industry studies, on the safety of BPA, none of them in this group found evidence that BPA had significant health impacts.  It turns out that this may have been because these industry studies used a strain of rat that was known to be insensitive to estrogen.  So that’s an example of choosing an animal model that shows, perhaps, the result that industries who profit by selling a certain kind of chemical might want to find in their research.”

What happens when powerful chemical industries oppose a BPA ban?  The ban becomes limited to… baby bottles.  It’s a start; however, this will obviously “result in ongoing human exposure and environmental damage.”

Speaking of human exposure, “BPA was detected in the urine of 91% of the population aged 6 to 79 years.”
Bisphenol A concentrations in the Canadian population, 2007 to 2009

The deliberate avoidance of true results outlines the importance of looking at numerous scientific trails and also paying attention to who funds a certain scientific study since it may be biased. If BPA studies are biased… could other studies by chemical companies regarding plastic be biased? This is a reason to question the safety of plastic.

I ere on the side of caution and avoid using plastic for health and environmental reasons. I buy bulk food, prepare food and choose glass packaging as an alternative.