In the last couple of months, BPA has made several notable media headlines, perpetuating confusion at the very least. What’s notable about them is that at least two of the articles have conclusions that are about as opposite as you can get with regard to the safety of this controversial chemical – at least on the surface. Let’s take a look below the surface and find out why these reports are in such contrast.
For a quick review, BPA (Bisphenol-A) is a synthetic petroleum-based organic compound usually used in making plastics and usually added to make plastics harder. It is also used in many other applications such as in the linings of aluminum water bottles and cans, cash register receipts, and dental sealants. BPA mimics the human estrogen hormone and can sort of act like our own once inside us.
The controversy about BPA is its safety once it is inside us. BPA not only can supersede our own estrogen but can, at higher levels, seem to be too much of a good thing causing enhanced estrogen activity linked (operative word) to breast cancer, early puberty, and altered baby boy anatomy, among other things. Science has convincing animal evidence of the perils of BPA. Since we can’t do experiments on humans, the evidence for determining human safety levels becomes more difficult and can take years. A burning question becomes: at what level does BPA become not safe for human exposure as measured by the amount of BPA going into and out of the body? At least that is one way to look at safety. Of course the industry’s position is that it is safe, even at all levels. After all, there are no immediate life threatening effects, which is how toxicologists typically analyze the safety of chemicals.So what's the problem with a little male infertility anyway, good for population control, right?
This summer, a government funded study concluded that BPA was not detected in the blood for 24 hours after “high” dietary exposure to BPA. Reporting articles in the media used the opportunity to cast doubt on the threat of BPA – you know, “It’s no big deal.” The chemical and canned food industry lauded the research with a “We told you so.”
Since then, a university based research article observed two events when breast tissue cells were exposed to BPA. The first was that high-risk non-cancerous breast cells turned cancerous when exposed to BPA. The other event occurred when breast cancer cells were exposed to BPA and then introduced to the cancer killing drug Tamoxifen. The Tamoxifen (the most commonly used breast cancer drug) appeared to be blocked by the BPA and not able to work effectively. The level of BPA exposure was consistent with what is typically found in human blood after a "typical dose". These “normal” BPA levels seemed to “flip a swtich” turning regular breast cells cancerous.
These are two very different studies. The first draws conclusions (despite many glaring flaws) and the second presents concerned evidence.
The government study by Teeguarden was his first research on BPA which may explain some of the oversight. The first major concern is that the researchers did not measure the amount of BPA actually ingested by the participants. They fed participants three cans of food during the day. Studies show that the amount of BPA in canned foods
varies greatly possibly based on many factors such as the original can manufacturer, the type of lining, the type of food and length of time in the can, and heat exposure. What the researchers measured instead was the BPA in the urine and claimed that urine output was representative of BPA input. Seriously? Were these humans in bubbles for the last few months with no exposure to any BPA? This assumption has raised eye brows even among non-scientists – it’s so egregious. Grist did an excellent follow-up on this research article going more into detail than I will here.
The second concern is that participants were asked to drink 3.5 liters of water during the day which for many people is a lot of fluid. Drinking excessive water may cause excessive BPA urine output but the possibility of dilution was not discussed.
The third error was concluding that there was no BPA in the blood when the level of detection used was only parts per billion. BPA research conducted by leading scientists often use parts per trillion for detecting BPA and note estrogen changes at this lower level. After all, our own hormones function in parts per trillion. That’s like saying there are no boulders in the field and then concluding there is nothing to worry about, but you didn’t bother to count all the rocks. Drawing the conclusion that there was no BPA in the blood using a limited level of detection (LOD) is pulling a SIGG. (Drawing a conclusion on something you couldn’t/didn’t measure.)
The fourth concern is the gross over-all conclusion that BPA is effectively excreted by urine, undetected in the blood and therefore poses no risk. WOW! Is it really that simple? Not. Teeguarden also went on to say that previous studies (hundreds, maybe thousands) were flawed; this is arrogance at best and not a very ethically scientific thing to say. Omitted from discussion was the fact that BPA is actually excreted more in the feces than in the urine. Also omitted from discussion was the fact that BPA has been found to be stored in muscles, bones, mammary glands and other tissues but most notably in fat where the concern is metabolic syndrome (diabetes) and estrogenetic changes. A recent study found that sweat had plenty of BPA in it despite the blood showing undetectable levels using parts per billion as the LOD. The BPA in the sweat is thought to mostly originate from fat cells (and linked to cancer). Scientists know BPA can be stored in several areas, the question is for how long, and does it cause “problems”.
So one study declared that BPA is safe because it was not detected in the blood and was effectively excreted in the urine. The other study shows BPA turning non-cancer cells into cancer and BPA interfering with the ability for the most common breast cancer drug to work effectively. Both of these studies, though very different, can not be correct with regard to safety. Most of the studies that minimize the affects of BPA are supported by the chemical and can industries. Most of the studies that raise concern for BPA are from independent scientists at universities, non-profits, and some governments. (No that there is any connection or anything.) Given the many glaring whoopsies in the first study, it is shocking that it even made it to print. It is disappointing to see the confusion extended to the media to the point where, given the second study, lives could be at stake.
So far six states have banned BPA to some degree, mostly for infant and children products, based on the overwhelming science. Unfortunately, BPA exposure in utero is where the greatest concern is. So banning baby bottles is after the fact. Better than nothing I suppose.
If something smells like smoke, the prudent thing to do is investigate it and tell people to get out until you are satisfied about the safety for all. Most people don’t simply ignore the smell of smoke or blow it off as no big deal. Why should concern for BPA be any different?