A Critical Look at the STATS Article Covering the BPA Debate

I was recently directed by my fiancé to this article by a non-profit organization called STATS. The article is called “Science suppressed: How America became obsessed with BPA” and focuses on the controvery over health impacts of Bisphenol-A (BPA).

Background on the BPA debate

BPABPA is chemical found in many products, including medical supplies, dental fillings, water bottles, baby bottles, CD’s, DVD’s, and food containers. BPA leaches out of these products over time and is frequently ingested.

When bisphenol-A is found in the blood, it acts as a weak endocrine disruptor, which means that its structure is similar enough to natural hormones (in this case, estrogen) to be capable of binding to hormone receptors. Studies on animal models suggest that BPA consumption can lead to numerous negative outcomes, including reproductive health problems, the early onset of puberty, obesity, increased rates of mammary and prostate cancers and neurological problems (to name a few).

The article written by STATS was particularly interesting because it presented a side of the debate about which I wasn’t familiar. It pointed out that numerous regulatory agencies including the European Food Safety Authory as well as agencies in Japan, Australia, New Zealand and the United States have reviewed the available literature and determined that BPA does NOT pose a significant health threat.

PET_bottlesThe literature on the health impacts of BPA is divided. Independent researchers often determine that BPA has harmful health effects while industry scientists decide that there are no harmful health effects at the levels in which people are currently encountering BPA.  So how did the government agencies decide which body of literature to base their findings on?

The agencies determined that the independent researchers often used experimental methods that were unsound.  For example, the route of BPA introduction for many of these studies was by injection rather than by ingestion. This is a significant problem because when BPA is ingested it is processed by the gastrointestinal tract.  In the liver, enzymes add a sugar molecule to BPA, which makes it easy to pass from the body and (most importantly) makes it unable to bind to estrogen receptors (so it is no longer an endocrine disrupter). Because most ingested BPA is made inert by this process, studies which inject BPA will dramatically overestimate the negative health effects associated with consuming the same concentration of the chemical orally.

The STATS article also points out that many of the discarded studies had low sample sizes, which means that there were too few animals in the study to draw any reliable conclusions.

A final complaint against the independent studies was that they only administered one dose concentration to the animals in their study.  Administering different dose concentrations (for example, using a control saline solution, a low dose, and a high dose) gives you a better idea of how the compound effects human health.  The impacts could be linear, meaning that the more you get the the worse the health effects or non-linear, meaning that small doses may cause no ill effects but passing a threshold concentration could induce serious effects (an all-or-nothing kind of effect).

An additional problem with administering only one dose is that you might mask an impurity in your BPA solution. If you administer two different doses and your BPA solution was well-manufactured, then there should be a difference in the magnitude of health effects if BPA is causing problems.  If the solution was not made well and some impurity in the solution is causing health problems, then hopefully the concentration of the impurity will be the same in the two doses and the health effects will be of the same magnitude in each treatment.

Based on these concerns, government agencies threw out much of the independent research and made their decisions based on industry research.

Commentary on the STATS article

BabyBottleThe remainder of the STATS article discusses how The Journal Sentinel reported only one side of the story and began America’s hysteria over the use of BPA in food and beverage containers.  I’m more interested in the actual science on BPA than I am about how reporters misrepresented the story (which is clearly important as well), so I won’t be commenting on that aspect of the STATS article.

The website claims that the STATS organization is non-partisan, which I took to mean that they would present both side of the argument in a balanced manner. Perhaps the point of this article was to scold The Journal Sentinel and not to present both sides of the debate, but the tone of the paper was definitely anti anyone who thinks BPA has negative health effects.

Frederick vom Saal, a prominent researcher on the negative health effects of BPA, is set up at the beginning of the article as being an overzealous fool. Many government agencies decided did not consider vom Saal’s findings in their official decisions because of unsound scientific methods (likely for the reasons outlined above) and vom Saal has taken a fairly extreme stance on the BPA debate.  He has likened BPA to the “biological equivalent of global warming” and his extreme stance sets him up to look like an unreliable source.

It should be noted, however, that vom Saal’s research is funded by the National Institute of Health. This means that a number of prominent medical researchers read vom Saal’s experimental protocol and determined that it was sound enough to be funded. His findings were then published in high-end, peer-reviewed journals, again attesting to the fact that vom Saal’s standing in the scientific community is sound.

But fine, I’ll buy that vom Saal’s opinion shouldn’t be the final word on the BPA debate. After setting vom Saal up to look like a zealous loony, they then attempt to discredit numerous other BPA researchers by noting any association with vom Saal that they may have had in the past.

For example, National Public Radio aired a Living on Earth episode which relied heavily on the input of Ana Soto. The STATS article is quick to note that Ana Soto collaborated with vom Saal in 1993 on one of the first papers to propose that BPA may be an endocrine disrupter (which it is). This is mentioned as a way to insinuate that Soto is as unreliable as vom Saal, which is an unfair conclusion to draw. First of all, collaborators can agree on results but disagree on their broader implications, suggesting that Soto could take a more down to earth stance on the BPA debate than vom Saal has taken.  Additionally, Soto has not collaborated with vom Saal again in 16 years. A lot can happen in a decade and a half and it’s possible that they haven’t collaborated again in that span of time because of differences in opinion.

The STATS article also tries to discredit a large group of independent researchers who signed a document called the Chapel Hill Consensus by pointing out that, you guessed it, vom Saal played a big role in the development of the document (he was the lead author).  You can’t discard the opinion of 38 prominent researchers because one researcher with whom you disagree was involved in the drafting of the document. All 38 of these researchers hail from respectable institutions across the country where they run successful research labs.

A big general problem with the BPA debate is that independent researchers often determine that BPA has negative effects on human health while industry researchers (with a vested interest in keeping BPA on the market) find that BPA is not harmful to human health (at least at the levels in which we currently ingest it). The STATS article rightly points out that immediately discrediting industry research is foolish and that lots of high quality research is conducted by industry groups. This still, however, doesn’t reconcile the problem with the fact that a large group of independent researchers are not coming to the same conclusions as the industry scientists.

Mouse_pupsThe article writes off this discrepancy by refering to the experimental method issues described above (e.g., injecting and not feeding BPA to animal subjects). While it is certaintly true that some experiments may not be very informative due to experimental design issues, there are plenty of experiments conducted by independent researchers that are finding harmful effects of BPA when conducting sound research.  For example, I mentioned an experiment in an earlier post in which BPA was fed (not injected) to a pregnant mouse, having a significant impact on the pup’s epigenome (see slide show explaining the research here).

If there is a discrepancy between industry and independent research findings, then we should give money to independent researchers who are employing sound experimental methods. Because BPA has the potential to be such a huge public health issue, it’s imperative that we get independent researchers to run the same test that industry researchers are running and compare their results. With so much at stake, we can’t afford to rely entirely on the findings of a group with vested interests.

Additionally, it seems to me as though there is a lot about potential effects of BPA that we don’t yet understand. For example, perhaps BPA is safe in adults and safe in children, but can have major effects on a developing embryo.  The tone of the STATS article would lead you to believe that everyone should conclude that BPA is totally safe at current exposure levels, but clearly there is a lot of work left to do.

I would certainly suggest reading the STATS article (if you have time, it’s 24 pages long) to get the often unheard other side of the story. It makes a good case that our panic over the use of BPA may be overblow, but I think that we still have a long road ahead of us before we can say with certaintly that BPA really isn’t a health hazard.


Conversion Troubles

Challenger1983Despite the fact that NASA’s spokesperson has admitted that NASA needs to make the jump to using the International System of Units (SI units), it will be building its next space shuttle using Imperial units. The international community is complaining that this will make their shuttle difficult to use by other countries because of the conversions that will be necessary for them to use it. Additionally, it shows that NASA hasn’t learned from the incident back in 1999 when it lost an unmanned probe due errors in unit conversions between metric software and SI systems on board. NASA argues that it would cost entirely too much to convert their equipment and blueprints to SI units instead of the archaic Imperial units they currently use.

It has always really frustrated me that the system of measurements I learned in school is not universal and, more importantly, is not the system being used by most scientists. We’re at enough of a disadvantage in science due to the fact that many of us speak different languages, can’t we at least have a universal measurement system?  I understand that it would take a lot of money to make the switch, but we’d pay to make the switch once and from now on everyone would be on the same page. Heck, Canada has already done it (mostly)!

For an article on NASA’s decision to stick with Imperial measurements, check this out.

The Plants Are Talking to Themselves…

Updates will be sparse for awhile owing to a hectic field work schedule, but fear not!  More updates are on their way soon!

Rick Karban of the University of California-Davis and his colleagues have discovered that plants the plants are talking to themselves.

Sagebrush_bloomsThese researchers discovered that when a sagebrush plant is cut (as when it has been bitten by a herbivore), it releases chemical compounds that communicate with other branches that are genetically identical. By communicating with itself in this way, the plant is able to coordinate a counter-attack to decrease its likelihood of being further damaged by herbivores.   The article can be found here.

Knowing that even plants are talking to themselves makes me feel a bit better about doing it myself.

How Should One Design Their Dissertation Topic?

Awhile back I had a debate with some of my PhD friends over the type of dissertation project that was most likely to land you in a position at a Research I institution. We fell into 2 main camps.


Off to get some data!

The first group thought it best to pick a series of “safe projects”.  Our definition of safe project was one that had a high probability of yielding results that would meet your predictions and would build upon an existing framework.  Despite the fact that your results wouldn’t be super sexy or surprising, these experiments would show that you understand how to conduct sound science and contribute to an existing body of work.

The second group thought it best to pick a risky project that, should it be successful, would dramatically change our understanding of a particular phenomenon. Should it prove unsuccessful, however, you’re left with pretty much nothing.

At the heart of the debate was our desire to be attractive candidates for the precious few positions in academia that open up each year. Of course, an even smaller subset of these academic positions are at Research I institutions, where a number of the individuals in the debate are striving to end up.

Completing a safe project will likely land you at an institution with a heavy emphasis on teaching. After years of publishing sound science and establishing your name, then you may be able to make the jump to a Research I institution eventually.

The problem with being at a school with a less strong emphasis on teaching is that they usually can’t afford to give as much money to start up a new lab as a school with a stronger research emphasis might. Additionally, heavy teaching loads mean less time in the lab or in the field and less time to write papers. So we decided that a safe project could land you in a Research I institution eventually, but it might be a pretty long journey before you make it there.

A risky project that works out and results in a number of publications in big name journals will certainly boost your chances of getting into a good research institution early in your career. The monetary and facility support that you receive here will be much better than at a teaching institution, making it easier for you to conduct lots of great experiments and acquire high quality students to work in your lab. What researcher could ask for more?

On the other hand, if your project idea doesn’t work out, then you’re worse-off than you would have been had you done a safe project.  A series of post-doc positions can fix this mistake, but you’re once again years away from the coveted Research I position.

So what project do you choose?  Well, like so many things in science, we’ve probably set up more of a dichotomy than actually exists.  I think that the best solution is to set up a big project with one sexy, but risky experiment and a series of safe experiments.  You need 3 chapters for your dissertation anyway, right? I think that taking a risk on at least one of the chapters is worth it for the potentially big pay-off.

I’d be interested in hearing feedback from other graduate students on how they are choosing their dissertation or post-doc projects.  Additionally, I’d love to hear feedback from post-docs or professors on what they think makes a successful dissertation project (where success is defined as ending up at a Research I institution).

(NOTE: I do understand that outstanding research is conducted at non-Research I institutions.  Also, I think teaching is vitally needed and noble pursuit. I did not mean to downplay the importance of either of these points, I just personally have my heart set on a position at a Research I institution.)

The Seafood Consumption Debate

On the front page of ScienceBlogs.com this weekend is a series of posts by blogger Jennifer Jacquet (of Guilty Planet) on the debate raging over seafood consumption. Although I applaud her willingness to take a strong stance and to provide a wider spectrum of voices on the issue, her stance that people need to cease consuming seafood entirely is, in my mind, counterproductive.

Fish_on_TrawlerIt’s becoming clear that we are on the road to the collapse of the fisheries industry due to intense and unsustainable overfishing. Individuals concerned with this trend have been making informed decisions about their seafood consumption with the help of sites such as Seafood Watch run by the Monterey Bay Aquarium. This site provides information about which fisheries are implementing sustainable techniques as well as information on fisheries that are being overexploited. Seafood eaters can make informed decisions about the types of practices that they want to support based on this information.

The blog Guilty Planet argues that it is not enough for people to switch to eating only particular seafood species as an increased demand on these species would result in their decline due to overexploitation. The blog proposes that the solution is to cease eating seafood altogether.  This stance isn’t going to make an appreciable dent in seafood consumption and is likely to alienate the very people that we need to be working with in order to bring about effective change.

An extreme stance such as this is likely to appeal to only a narrow range of supporters, limiting its overall effectiveness.  The vast majority of seafood consumers do not even abide by the guidelines for sustainable fish consumption, suggesting that an even smaller handful will be willing to give it up entirely.

To be fair, Guilty Planet concedes that few people will likely adopt a no-seafood policy.  She hopes that by providing a more extreme position newcomers to the debate will find other solutions (such as eating fish from sustainable fisheries or cutting down their consumption) more palatable. I worry that publicity for the “Stop Eating Seafood Movement” will scare away the newcomers who are starting to become concerned with the decline of overexploited species and are looking for an easy way to make some positive changes. When they see the sacrifices that we’re asking them to make by cutting seafood out entirely, I worry that they’ll give up on making changes altogether. Let’s be honest, we’re not going to get the majority of Americans onboard unless you make conservation seem easy (although it clearly isn’t).

Essaouira,_Fish_MarketBut the real problem lies in the message that this stance sends to the seafood industry and, in particular, the message that it sends to individuals in the industry that have been working hard to implement sustainable techniques. They were once “rewarded” for their sustainable behavior by the increased patronage of sustainability-savy individuals (with the help of sites like Seafood Watch).  The new message that we’re sending with a call for a boycott of seafood is that we’re abandoning the industry altogether (including those working on making positive changes) and we’re unconcerned with their situation. After all, the fishermen would also prefer that marine species were not in decline as this business feeds their families.

The small decline in consumption that this stance may generate will certainly put a bad taste in the mouths of the industry with which we need to cooperate. They need to feed their families and we need them to change the way that they do their job. Without collaboration and wide-scale changes in practice, the overfishing problem will not be resolved.

There are people all over the world who rely on seafood as an important protein source. To me this implies that the solution can not be reached by pleas for a removal of seafood from one’s diet. As long as there are fish to catch, there will always be fishermen. Coming to terms with this fact necesitates that we keep lines of communication open with the seafood industry so that they will be open to our suggestions and technologies in the years to come.

To reiterate, Guilty Planet and I on the same side.  We both want to see major reforms in the way seafood species are collected and consumed so we can reverse the trends of decline. I also agree individuals should think carefully about the diet choices they make as well. I personally limit my seafood consumption and consult Seafood Watch before making a purchase.  Jennifer and I simply differ in the method in which we think is the most effective in bringing about change.

The Worst Advertisement I’ve Ever Seen

I was browsing Science Daily today and noticed the following advertisement:

HarrisonFordI spent awhile trying to figure out if it was a joke or not and have come to the conclusion that this group actually believes that people will sign their petition just because a haggard looking Harrison Ford thinks that they should.

Does this sort of advertising actually work on people? I personally don’t know anything about what Harrison Ford stands for.  Why would I blindly follow a man about whose belief system I know nothing?  I know he made a darn good Indiana Jones, but I don’t even know which political party he generally identifies with.

Too bad they didn’t use a picture of Harrison Ford from 20 or so years ago.  Maybe then I would have signed their petition. Or maybe if Hugh Jackman thought I should sign it…..

More Scientist Humor

In an earlier post I listed species and gene names that were clearly conceived of by scientists who had a sense of humor.  I have another one to add to the list.

Phallus_drewesiiA newly discovered mushroom species found in West Africa has recently been named Phallus drewesii (Latin translation: Drewes’ penis).  It was named by a colleague after a California Academy of Science curator named Bob Drewes who explains, “I am utterly delighted. The funny thing is that it is the second smallest known mushroom in this genus and it grows sideways, almost limp.”  Clearly, this is a man with a good sense of humor.

Check out this article for the original story.

Below is a video of the man himself discussing the function of snake venom: