Nano Active: Battle of the Sexes: Men Found to Have Higher Levels of BPA in Their Blood Than Women

Thursday, October 3, 2013

Battle of the Sexes: Men Found to Have Higher Levels of BPA in Their Blood Than Women

There are many studies examining the levels of Bisphenol A (BPA) and other endocrine disruptors present in the environment, and a large number of studies investigating the mechanisms or pathways these chemicals may take to wreak havoc on living things.

BPA and several other endocrine disruptors have been linked to a whole host of health problems, including but not limited to cancer, low testosterone and low sperm motility, miscarriages, and birth defects.

How much do I really have in my body?

Sure, that’s all fine and dandy if you can tell me just how a certain amount of BPA can affect my health, but really, is BPA even present in these amounts in my body? Or are the amounts required to elicit these hazardous consequences much too large to have any meaning biologically?

In 2002, a team of researchers in Japan set out to answer a few simple, yet highly important questions: 1) How much BPA is present in human blood; 2) Are there any differences in BPA levels between men and women?; and 3) What are the relationships between BPA and sex hormones present in our bodies?

Guinea Pigs

Well, not ACTUAL guinea pigs, but real human beings…a group of 14 healthy women, a group of 16 women with diagnosed polycystic ovary syndrome (PCOS), and a group of 11 healthy men were recruited to give blood serum samples for this study.

What they found…

What this team of researchers found was that serum BPA levels were significantly higher in healthy men than in healthy women. Serum BPA levels in these healthy men were 1.49 +/- 0.11 ng/mL, while serum BPA levels in healthy women were 0.64 +/- 0.10 ng/mL (CONVERT TO PPM…..). Also, they found that serum BPA levels significantly correlated with both free testosterone levels and total testosterone levels. Interestingly, serum BPA levels were not significantly correlated with any other sex-related hormone, including luteinizing hormone, follicle stimulating hormone, prolactin, and estradiol. Finally, these levels found in both men and women were HIGHER than the levels reported to cause problems

Why do the men have it all?

Why did the men in this study have a significantly higher level of the chemical in their blood than women? Well, this study didn’t explicitly study the “why” side of things; however, a few possibilities come to mind.

One thought is that BPA may somehow disrupt the feedback control of testosterone hydroxylation. As the body produces testosterone, it produces enough up until a “magic point” where a feedback mechanism kicks in and tells the body to “hey, man! There’s too much testosterone here! Back off!”. Once levels drop to a certain level, production of testosterone can start again and so the cycle continues. What might be going on here is that BPA somehow manages to interfere with this feedback mechanism, and somehow manages to “confuse” the system so that it no longer instructs the body to stop making testosterone. Therefore, the body will just keep making more and more, and as a result of the BPA exposure, will not send the message for the excess to be destroyed.

Another possible mechanism is that BPA acts as a sort of antagonist for the naturally produced sex-hormones in the body, in this case; testosterone. BPA could be competing against testosterone for binding onto the androgen receptor, thereby somehow disrupting the androgen-estrogen balance within the body.

You didn’t answer my question: Why do men have higher levels of BPA in their system than women?

Well, I did answer it in a round-about way above, but again, this was more of an “observational” study and didn’t explicitly examine the mechanisms or reasons behind these differences. However, one thing that should jump out to you is this: BPA was found to be significantly correlated to testosterone levels and no other sex-related hormone in the body. Men have higher levels of testosterone by nature than women. Therefore, one can guess that because men have greater levels of testosterone in their bodies and BPA is significantly correlated with testosterone levels, then men will have greater levels of BPA in their blood. Voila!

More detailed studies will shed further light on this subject, but in the meantime, the results of this study should give a tiny clue as to how endocrine disruptors behave in the human body.

Source: Takeuchi, T., and Tsutsumi, O. 2002. Serum Bisphenol A Concentrations Showed Gender Differences, Possibly Linked to Androgen Levels. Biochemical and Biophysical Research Communications 291: 76-78.

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ABOUT THE AUTHORS

LEWIS PERDUE

I have an academic and vocational background in biology, organic chemistry, environmental science, high-energy physics and nuclear engineering.

I graduated from Cornell University with a B.S. degree in 1972.

My serious lifelong involvement with science began as a uber-geek that involved university graduate-level work as a teen. That eventually landed me as a finalist in the Westinghouse (now Intel) Science Talent Search. I also won several prizes at the 1966 International Science Fair for a propulsion engine I designed to use the solar flux for fuel.

NASA, the U.S. Air Force and the National Academy of Sciences awarded that work numerous citations. As a result, I was able to attend summer school in the Aerospace Engineering at Mississippi State University.

The next summer, I worked an internship at Westinghouse where I helped improve spectrographic test equipment and prototyped solar flux instruments for a Mars fly-by. (At least one of these I hand-crafted flew in the Mariner satellites).

During that internship, I also calibrated neutron density devices for military and civilian nuclear reactors. To the best of my knowledge, no reactors have ever melted down or malfunctioned because of this work. Of course, the military program was classified, so only the NSA knows if I blew something up.

Despite my original research in physics, I maintained my education and knowledge of biology from an early age. I was fortunate to have been mentored and tutored during my high school years by Dr. Arthur C. Guyton, professor, medical researcher and the author of the world's best-selling human physiology textbook

I majored in biology with an emphasis on Ecology, Evolution And Systematics at Cornell University's College of Agriculture and Life Sciences where I graduated with distinction in 1972.

While at Cornell, I worked full-time as a newspaper reporter, this time for the Ithaca Journal.

My A+ grades in organic chemistry and discovery of more than two dozen errors in the class textbook (primarily in quantum bonding orbitals) prompted Cornell's chemistry department to recruit me as a major in their department.

Unfortunately, I couldn't find a way to support myself except as a newspaper reporter. While I was willing to do that, the prospects for financial survival for Ph.D. work were a grim. I could study, or I could eat. Not both. And that deflected my vocational choices toward full-time writing and part-time scientist.

Over the intervening years, I've continued to stay current through careful reading of scientific journals and my study of updated textbooks particularly on quantum physics, and molecular genetics.

I've been the founder or early-stage staffer in three technology start-ups, worked as a Washington (D.C.) Correspondent, a Congressional and gubernatorial aide and taught on the faculties at Cornell and UCLA.

In 2012, I discovered that thousands of acres of California's finest vineyards are drip-irrigated with highly treated, recycled sewage water.

That discovery led me to dig deeper into compounds that are biologically active in nano and pico concentrations -- potentially Endocrine Disrupting Compounds and other chemicals of emerging concern.

This totally re-invigorated my molecular biology and organic chemistry enthusiasms, and led me to found this blog and initiate the online partnership with biologist Becca Yeamans.

Unless you have had enough already, you can click here for more.

BECCA YEAMANS

Becca L. Yeamans, is a biomedical scientist with extensive research and laboratory experience in clinical research trials in immunology and neurology. Educated in environmental sciences, she is the author of several papers in peer-reviewed journals,

She was born and raised in the Northeast Kingdom of Vermont, and also freelances as a writer specializing in the Environmental Sciences as well as the world of wine, enology, and viticulture.

She received her Bachelor of Science in Biology in 2004 from Saint Michael’s College in Colchester, Vermont and her Master of Science in Environmental Sciences (with a focus in Ecology) in 2011 from the University of Virginia in Charlottesville, Virginia.

Her undergraduate research focused on species diversity of ants and other ground-dwelling macroinvertebrates in fragmented habitats caused by human interference, with implications for using ants as potential indicators of environmental health.

This work has since led to several published articles in peer-reviewed journals.

Her graduate work at the University of Virginia resulted in her excelling in course and laboratory work throughout the disciplines of geology, atmospheric science, hydrology, and ecology.

Her strong writing and research skills led to successful grant applications to fund her Masters’ thesis, entitled “Ecological and Evolutionary Shifts in Pollen Chemistry and Their Implications for Pollinators”, which shed light on some of the important questions in the field of pollination evolutionary ecology and is a key contributor to the study of pollen nutritional quality for bees.

Her research experience extends from the Environmental Sciences to biomedical research and also clinical research. While working in a Harvard Medical School-affiliated Immunology laboratory in Boston, MA, her hard work and dedication to the world of research led to her establishment of a human-to-mouse skin transplantation model to study burn-injury; a first for the laboratory.

Her vast research experience has also included managing and administering clinical research trials in Neurology, specifically focused on symptom management and therapies in Multiple Sclerosis.

Aside from published peer-reviewed journal articles based on her past work, Becca’s passion for writing took off with the establishment of her blog, The Academic Wino.

The Academic Wino is a highly technical blog, and is dedicated to dissecting and reviewing current research in enology and viticulture, while providing insights and thoughts on the current state of research related to wine.

The articles reviewed span nearly every aspect of academia, and provide a public forum to discuss the state of research related to wine. She is also a freelance writer for several wine-related online publications, in addition to managing her own personal blog.

Becca Yeamans lives in Charlottesville, Virginia with her loving fiancé, their two dogs, Coaty the Greyhound and Crystal the Golden Retriever, as well as their cat, Cassie.

When she’s not up to her elbows in peer-reviewed scientific journals, she can be found spending time with her human and animal family at a winery, microbrewery, or up in the mountains.