Wednesday, May 12, 2010

Some Reassuring Opinions on Bisphenol A

I came across a link to a scientific opinion piece about bisphenol A (BPA) recently, and thought I'd post about it here. It should reassure those of us whose babies were fed from bottles made before the BPA uproar forced manufacturers to switch to different plastics. The author of this piece, and a companion piece written for a more general audience, is Richard Sharpe, a scientist at the prestigious Medical Research Council in the UK. As far as I can tell, he has no connection with the plastics industry. In fact, a quick survey of some of his publications indicates that he is concerned about the effects of some environmental influences on human reproduction- just not BPA.

Dr. Sharpe argues that there were design flaws in the study that ignited all of the concern about BPA, and that multiple later studies have failed to replicate that original finding. A recent study again failed to replicate the findings, and Dr. Sharpe thinks that this should be the end of the argument.

Of course, the original study's authors refute this argument in a letter to the journal that published Dr. Sharpe's opinion piece. There is a published rebuttal to this letter as well, which unfortunately, I can't access.

All of this back-and-forth is about whether or not BPA is likely to cause reproductive issues. There is also an argument about whether or not BPA is likely to leach from the bottles in any appreciable amount under the conditions that they are usually used. (A couple of years ago, I had references on that argument, too, but I can't find them right now- suffice to say, some groups say "Yes! Heaps of BPA leaches out!" and other groups say "No! Those first groups were doing their studies all wrong!" Back when I was making the decision about whether to change Pumpkin's bottles- this uproar really hit the mainstream when she was about 9 months old- I decided that I believed the second group more.)

Scientific arguments like this are actually not that uncommon. What is unusual here is the extent to which this has played out in the "regular" press and the fact that public opinion has already forced bottle manufacturers to change the composition of their bottles. In my opinion, public opinion was driven largely by a report from the Center for Health, Environment and Justice- which is not exactly a neutral, science-based organization. To me, this is an example of the politicization of science, just as much as the shenanigans pulled during the Bush administration were, and it is just as wrong. Science should be about testing hypotheses and reporting facts, and not about spin. As Daniel Patrick Moynihan said, "Everyone is entitled to his own opinion, but not his own facts."

The problem with arguments like these is that it is next to impossible for a non-expert, even a scientist in a related discipline, to really sort out who is right.  In these situations, it is helpful to get a feeling for what the majority of experts in the field think. And luckily, someone has surveyed toxicologists on their opinions about what environmental exposures are harmful. Only 9% rated BPA as a high risk. (There is a lot of other interesting data in that link, too.)

So why does this all matter if the decision has been made? BPA is gone from baby bottles. Well, a lot of us still have older bottles. About 1/3 of the pumped milk Petunia gets, for instance, is delivered in Pumpkin's old BPA-containing bottles.  But more fundamentally,  it bothers me to see science used to force a change when the data doesn't necessarily support that change. The BPA was replaced with other chemicals, not fairy dust. Who knows whether those chemicals will be deemed safe in 15 years? I can tell you that at least one of the reformulations produced an inferior bottle. We needed additional bottles for Petunia, so we bought some new ones from the same brand we used with Pumpkin. There were two options, and we bought some of each. We've pretty much stopped using one of the types of bottles, because it didn't rinse clean in the dishwasher. I didn't like the fact that I had to rewash those bottles by hand almost every time. Besides, if the dishwasher soap is sticking to the bottle, what else is?

I came across the link to the opinion piece by Dr. Sharpe in the comments on a post from Science-Based Medicine about the recent report from the President's Cancer Panel. The entire post is worth a read, if you have the time.

6 comments:

  1. mary d6:47 AM

    Our 2nd baby is due in about 5 weeks and we're trying to decide whether to buy new bottles for him or use the ones his big brother used 4 years ago. This will help us decide, so thank you for doing this post. Lots of good information out there, it's finding it that's hard, so thank you.

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  2. You're welcome, @mary d.

    We obviously went with the some old, some new approach. I purposely mix them up so that she gets roughly half and half. If there is a problem with any chemical (BPA or whatever they're using now in bottles), it will be dose dependent, and there will be a clearance mechanism by which it leaves the body. So I figured we'd just decrease her dose of any one thing.

    Of course, we mostly breastfeed, so this wasn't quite as big of an issue for me as it might have been if we were exclusively bottle-feeding. She only gets a couple of bottles a day now, and never got more than 4 a day.

    Congrats on the new baby!

    ReplyDelete
  3. Let me know if you'd like to read the rebuttal, I managed to get a copy. I don't have your email addy - but I think you can get mine off this comment? If not it should email me subsequent comments...

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  4. @Today Wendy- my email is wandsci AT gmail DOT com.

    Thanks!

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  5. mary d4:23 PM

    Yeah, the plan is to breastfeed -- did fine with the first one but you never know. :) But you still need the bottles at daycare and such. You're right, it's a MUCH smaller deal if it's a bottle or two a day as opposed to all the time.

    ReplyDelete
  6. Great post as usual!

    Chiming in late here, but FWIW we used glass bottles before DS was of throwing age, and we always avoided heating the bottles. (Very unscientific, I know.)

    ReplyDelete

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