Just the mention of bisphenol A (BPA) strikes terror into many hearts. If you go by media accounts you might think that this is the very chemical that is going to unravel the fabric of society. But did you know that there is a Dr. Hyde side to this Mr. Jekyll?
Gentlemen, how would you like to boost your testosterone levels? Apparently many of you would, seeing that over a million prescriptions are written every year for waning libidos in North America. And ladies, if you’re pregnant, how about reducing the risk of an underweight baby, a condition that could have serious life-long consequences? Seniors, wouldn’t you like to battle aging with antioxidants? Well, all you have to do is increase your intake of bisphenol A (BPA)! Right, the very chemical that can leach out of certain plastics and can liners and which, according to some, is the devil incarnate.
Where is the evidence for BPA’s surprising benefits? It’s right there in the scientific literature. All you have to do is look. A large trial that surveyed 715 Italian men found that the more bisphenol A they excreted in their urine, the more testosterone they had circulating in their blood. In another study, when mice were treated with BPA during pregnancy and lactation, their pups at weaning were heavier and longer than control animals. This difference was no longer apparent when they reached adulthood, so the BPA was not increasing their susceptibility to obesity. And bisphenol A, a polyphenol by chemical category, is a recognized antioxidant, added, for example, to PVC piping to reduce damage by oxygen, the same sort of damage that has been linked with human aging.
So, is anyone ready to start taking BPA supplements? I hope not, because what you’ve just read is utter nonsense! The information was drawn from legitimate scientific publications but I twisted it way out of context! The Italian study, for example, did find higher testosterone levels, albeit still within the normal range. And of course just because there was an association with BPA in the urine, one cannot conclude that the BPA caused testosterone to increase. Why mess with your mind like this? Because it is important to drive home the point that with some 1,345,000 scientific papers being published every year in the world’s 23,750 journals, it is possible to back up most any notion with carefully cherry-picked data. The debate about Bisphenol A is an excellent example of selective data mining, with both the “pro” and “anti” sides being guilty to some, although not equal, extent.
The more bisphenol A is in the news, the more acrimonious and self-serving the debates seem to get. On one side we have some scientists stirring the pot with statements like “The science is clear and the findings are not just scary, they are horrific. When you feed a baby out of a clear, hard plastic bottle, it’s like giving the baby a birth control pill.” This is absurd. The science isn’t clear, it’s quite murky. If it were all clear, we wouldn’t be having such bitter debates.
On the other hand, the BPA defenders, mostly with industrial connections, claim that BPA has been safely used for fifty years and presents no risk to humans. This is a hollow claim. True, nobody has ever experienced an acute reaction from traces of BPA leached out of a polycarbonate bottle, but that is not the kind of risk we’re worried about. The concern is over the possibility of subtle effects that may turn up after long term exposure to minute amounts of BPA, or health problems that may be manifested in the distant future if exposure occurs at a crucial stage of development. Such concerns are legitimate and are based upon suggestive, but certainly not conclusive, evidence.
Some researchers have linked the estrogenic properties of BPA with a predisposition to prostate and breast cancer in rodents, but others have not been able to reproduce these results. Such failures have precipitated tart arguments about using animals that may be insensitive to such effects. But then how can we draw any inference for humans if the effect is so foggy that it depends on slight genetic differences between closely related rodents?
There are also literature reports about the possibility of heartbeat irregularities in pregnant women, but these are based on “proarrhythmic activity” in muscle cells isolated from mice and rats. The relevance of this to humans is debatable. Other studies have claimed that two year old girls whose mothers encountered the most BPA in their pregnancy were more aggressive than normal. A subjective evaluation, which may or may not be real, and may have absolutely nothing to do with BPA. Perhaps the altered behavior, if it exists, is caused by some other of the thousands of chemicals present in the body whose levels parallel that of BPA. And the fact is that at any given time, there are thousands and thousands of natural as well as synthetic chemicals cruising through our body.
Drink a cup of coffee and you’ve introduced over a thousand compounds into your bloodstream. Eat an apple, you’ve added another three hundred, including acetaldehyde and formaldehyde, known carcinogens. Six hundred more from a potato. Have some hummus and you’ve downed a few hundred more chemicals, including a healthy selection of compounds with greater estrogenic activity than bisphenol A. Add to this exposure to drugs, cleaning agents, cosmetics, agricultural chemicals and building materials. We really do live in a “chemical soup,” as the activists are fond of pointing out, but in terms of risk, that is neither here nor there. Risk depends on which chemicals and in what amounts.
I suspect that many of the thousands of compounds that show up in our urine would raise various concerns if investigated with the same vigour as BPA. The attention being paid to this one compound borders on the obsessive. Exposure certainly may have some biological effects, but one thing we can conclude is that whatever these may be, they are not dramatic. If they were, they would have revealed themselves in the literally thousands of BPA studies that have been carried out by researchers around the world. These studies have been extensively and exhaustively evaluated by various regulatory agencies. What conclusion did these agencies come to? Certainly not the one the Huffington Post arrived at with the headline “BPA Wrecks Sex, Fouls Food-and Probably Worse.”
The general consensus is that while it may be appropriate to apply the precautionary principle and take some measures to reduce BPA exposure during a baby’s developmental stage, the ferocious emotional attacks unleashed against this chemical are not justified by the available science. And it’s unlikely that pumping more dollars into BPA research is going to resolve a debate that has already gone way beyond its importance. Let’s face it, the “intervention” study that could ultimately shed light on the situation can never be carried out. Subjects cannot be exposed to varying amounts of BPA over decades. So let’s be realistic. Polycarbonate plastics and resins made with bisphenol A are so useful and so ingrained in commerce that their elimination is out of the question. Measures are being taken to minimize infant exposure, and companies are searching for alternative can liners, if for no other reason, than to get the BPA monkey off their backs. Some cash register receipt inks harbour BPA and alternatives are being examined here as well.
It is time to reiterate that everything in life has some degree of risk, that a single chemical out of the literally hundreds of thousands to which we are regularly exposed is unlikely to have a major impact on health, and that debates about whatever impact bisphenol A may have will never be resolved. It is time to move on and think about spending research dollars on other more important health care issues. We have a few of those, don’t we?