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    What Do We Really Know About BPA And Fertility?
    By Steve Hentges | August 8th 2013 08:00 AM | 12 comments | Print | E-mail | Track Comments
    About Steve

    Steven G. Hentges holds a Ph.D. in organic chemistry from Stanford University and a B.S. in chemistry from the University of Minnesota. He is the...

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    Last week, a study published in the journal Human Reproduction reported that bisphenol-A (BPA), a compound widely used to make polycarbonate plastic and epoxy resins, altered maturation of human oocytes in vitro.

    Specifically, at high concentrations of BPA, oocyte maturation decreased while the incidence of oocyte degeneration increased. In an accompanying press release, the authors suggested that BPA “may cause a significant disruption to the fundamentals of the human reproductive process and may play a role in human infertility.”

    But does this study really support such a far-reaching implication, and are the results consistent with other studies that directly and comprehensively examined the potential for BPA to affect reproduction?

    In vitro studies such as this are useful, as a preliminary study to generate a hypothesis, or to examine the mechanism of an established effect. However, it would overstate the results of this study to say that it establishes an effect in humans. In the case of BPA, robust data is available to help us interpret these findings and, in particular, demonstrate why this study is of limited utility in identifying and evaluating health risks in people.
     

    Perhaps most importantly, the study is of questionable physiological relevance since the BPA concentrations showing effects on maturation are vastly higher than an average person’s daily intake of BPA. Extensive biomonitoring data from CDC and others show that typical human exposure to BPA from all sources is extremely low, on the order of a couple micrograms per day for a typical adult.


    Image credit: BevNet

    Since BPA is rapidly metabolized and eliminated from the body with a half-life of only a few hours (Doerge et al., 2010), it does not accumulate in the body and peak concentrations of BPA in serum are undetectable (< 0.3 ppb) even with an atypically high dietary intake of BPA (Teeguarden et al., 2011). The authors point to a 2002 study from Japanese authors claiming low ppb levels of BPA in serum and follicular fluid (Ikezuki et al. 2002), but neglected to note that the analytical method used in that study was subsequently found to be invalid for measurement of BPA in human samples (Fukata et al., 2006).

    In contrast, the concentration showing a clear effect on oocyte maturation in this study was 20,000 ppb, with no apparent effect on maturation at 20 ppb and borderline significance at 200 ppb.

    The authors do note that the study may have been impacted by the use of "clinically discarded” oocytes, mostly from infertile patients, that had not matured in vivo even after hormonal stimulation. They acknowledge that this “potentially compromised material,” could “reduce the relevance of our findings to a more normal population.”


    Although this new study has significant limitations to clinical relevance, the potential for BPA to affect reproduction has been carefully examined with multi-generation studies in multiple species and strains of laboratory animals (for example, Ema et al., 2001; Tyl et al., 2002; Tyl et al., 2008).

    These studies, published in the peer-reviewed scientific literature but not cited in this new study, consistently have concluded that BPA does not affect fertility or other reproductive parameters at any dose even remotely close to actual human exposure levels.

    Based on the weight of scientific evidence from these studies and others, regulators have repeatedly concluded that BPA is not a reproductive toxicant. In fact, the FDA recently updated its position on BPA, stating its “current assessment is that BPA is safe at the very low levels that occur in some foods.”

    Comments

    Ladislav Kocbach
    As we can read in Dr. Hentges' intro: Steven G. Hentges holds a Ph.D. in organic chemistry from Stanford University and a B.S. in chemistry from the University of Minnesota. He is the Executive Director of the Polycarbonate/BPA Global Group of the American Chemistry Council (ACC). This unit of ACC promotes the business interests and welfare of the global polycarbonate and bisphenol A industry with a comprehensive program that includes health and environmental research along with a wide range of communications and advocacy activities.So this article should be posted under "Advocacy activities" and not under "PHYSICAL SCIENCES/CHEMISTRY"? Am I right or wrong? Since I am not any specialist in biochemistry, I would like to know. Where goes the boarder between science and advocacy?

    I see that in general reference the issue is not so very simple -  as an example and indicator - one can see http://en.wikipedia.org/wiki/Bisphenol_A
    It is an age old problem, trying to figure out how to convince someone of something, when there livelihood is dependent upon them NOT believing it. The chemical companies and their scientists will continue to tell you it's safe until the government stops them. The Canadian government has declared BPA a toxic chemical, but I guess it's a climate thing, once its South of the Border, it is "Okay". The French Government has banned it from any contact with food stuffs, but hey they're "french", they are extreme when it comes to their food.

    In 2007 an "Expert Panel" on BPA came to this conclusion:

    "The published scientific literature on human and animal exposure to low doses of BPA in
    relation to in vitro mechanistic studies reveals that human exposure to BPA is within the range
    that is predicted to be biologically active in over 95% of people sampled. The wide range of
    adverse effects of low doses of BPA in laboratory animals exposed both during development
    and in adulthood is a great cause for concern with regard to the potential for similar adverse
    effects in humans."

    - Chapel Hill bisphenol A expert panel consensus statement:
    Integration of mechanisms, effects in animals and potential to impact human health at current levels of exposure

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2967230/

    Oh, but they are ALL wrong and this Doctor, getting paid by the Chemical companies that are profiting from BPA, is the right one.
    So, where does that leave us? With a government with too much self interest to act and the old adage, BUYER BEWARE. Eventually the power of information and the internet will hit their pocketbooks and the people will change things.

    By the way, I have no University degree, but I am capable of reading published studies. Perhaps Doctor Hentges would care to comment on this study?

    Ladislav Kocbach
    One can also read a news article here on Science 2.0 - showing the opposite perspective.It is called Chemophobia - The Unnatural Fixation Of Activists
    http://www.science20.com/news_articles/chemophobia_unnatural_fixation_ac... and unfortunately a good point is spoiled by describing a general problem by adding the "Fixation Of Activists" to the title. The News Stuff here is not really hiding their "religion", far far to the asymptotic right.

    It seems clear that this article is in response to one published a few weeks earlier.

    http://www.science20.com/news_articles/bpa_linked_disruption_human_ferti...

    Dear Sir,
    Are you suggesting that a "news article" published on this sight, citing one source discussing the "general phobia of chemicals" can in any way refute the published study I listed where 38 individual scientists, doctors, chemists, etc., analyze all the relevant, published studies pertaining to ONE particular chemical - BPA - and arrive at a consensus that it is dangerous for human consumption?
    Perhaps you should read the cited paper. In his introduction to the paper Professor Gribble states: “ A Basic premise of this paper is that the “dose makes the poison” - everything is toxic at some level.”
    Recent research has shown that this premise is flawed and there are chemicals that can and do effect the human body at low doses.

    By his rational, people have a general phobia of snakes. Most snakes are not poisonous, hence we shouldn't worry about coming into contact with them since they are a naturally occurring part of our world?

    No, there are poisonous chemicals, just like there are poisonous snakes and people need to be educated about them so they can protect themselves and their families.

    Hank
    So you are contending BPA, which has been around since the 1800s, is now suddenly causing cancer at any dose?  Since you are selling something, let's see real data to back up your claim. The review you listed said no such thing.
    Honestly, was that a serious attempt to engage in scientific discussion? No one with an informed opinion on BPA is talking about links to cancer. I never mentioned it in my comments and there is little evidence to support it.

    Ok, let me give this a go!

    All natural LEAD, been used for drinking glasses and plates over a 1000 years ago. For most of the last 100 years it was used in paint. More recently it was used to seal the pipes of your drinking water. Yes folks, lead is safe for you and your kiddies.

    Myself, I help women in Thailand who are struggling with infertility. I’m pretty sure that posting on this farcical website isn’t going to profit me financially, UNLIKE YOURSELF.

    Oh, by the way, why is it that after you posted ONE comment under this article, your automated notification system bombed my inbox with over 20 emails indicating additional comments?

    Perhaps in your reply to this comment you could mention Snowden or the new iPhone and that will get your webpage to show up in more search results? Oops, I just did!
    I won't be contributing further.

    Hank
    You're making the point that it is a mass media fad that is being used by activists for fundraising and not evidence-based. At least not yet. If it is evience-based I will be first to turn on it.

    As has been noted many times, there are a dozen carcinogens in your Thanksgiving dinner that cause cancer in rats - they would be banned, except they are natural. 

    Sorry about the comment notification. Spammers make no effort to get seen and they are way ahead of Google so if they get through that the comment notification goes off - but they were probably deleted by the time you arrived. Blaming this site for Google being unable to stop spammers makes as much sense as blaming BPA for infertility, though.
    Gerhard Adam
    Blaming this site for Google being unable to stop spammers makes as much sense as blaming BPA for infertility, though.
    So, you're refuting this study?

    http://humrep.oxfordjournals.org/content/early/2013/07/30/humrep.det312....

    Mundus vult decipi
    Hank
    I'm the one who posted the release about it.

    I am pleased you finally found a paper written by biologists you didn't declare was stupid, though. You just should have actually read it before abandoning your skepticism about all things biology.
    Gerhard Adam
    I'm the one who posted the release about it.
    Meaning what?  Presumably you also posted the article about fracking being linked to Ohio earthquakes, but since I know how you vote, I doubt you believe that one either.
    Mundus vult decipi
    Hank
    You don't know anything about me, other than that I wrote a book noting the anti-science positions of progressives, precisely because so many people in science media insist those flaws are only on the right. Fracking and BPA studies get posted because they are important topics that people are talking about. So do lots of other things.

    Do you have anything at all to say about Steve's piece? I cannot fathom why you want to pollute his column with off-topic nonsense.