Yesterday, both
href="http://scienceblogs.com/terrasig/2007/02/lavender_and_tea_tree_oils_may.php">Abel
and I posted about the unexpected effects of lavender and tea-tree
oils: they've been implicated as causing gynecomastia in boys.
href="http://www.blogpulse.com/search?query=gynecomastia&image22.x=20&image22.y=18">Blogpulse
indicates that the Blogosphere has reacted quite a bit to this: the
blog at
href="http://blog.wired.com/biotech/2007/02/lavender_oils_f.html">Wired
News picked it up, as did
href="http://skepchick.org/blog/?p=377">Skepchick,
href="http://dailytroll.com/?p=1219">I see Invisible People,
href="http://www.plasticized.com/2007/02/tea_tree_oils_a.html">Plasticized,
href="http://aromaconnection.typepad.com/the_aroma_connection/2007/02/lavender_and_te.html">Aromaconnection,
href="http://www.scienceblog.com/cms/lavender-tea-tree-oils-may-cause-breast-growth-in-boys-12497.html">Science
Blog (not to be confused with ScienceBlogs) and about several
others.
This morning, I see that there was a conference (
href="http://www.healthandenvironment.org/fertilitysummit">2007
UCSF-CHE Summit on Environmental Challenges to Reproductive Health and
Fertility) in California to examine and discuss what may be a
widespread, more general, problem in this world of ours:
href="http://www.nrdc.org/health/effects/qendoc.asp">endocrine
disruptors.
In part, the concern is due to statements such as this, from the
href="http://www.healthandenvironment.org/?module=uploads&func=download&fileId=222">Vallombrosa
Concensus Statement (pdf):
[D]atafrom the US Centers for Disease Control and
Prevention show that impaired fecundity over the last two decades
appears to have increased in all reproductive age groups, but most
sharply in younger women (under age 25). These data, together with a
growing body of epidemiological literature and many experimental
research results showing male and female fertility-related impairment
in laboratory animals caused by a wide array of modern chemicals,
implicate environmental factors also as possible contributors to human
infertility.
You may recall that I concluded with the remark, "In general, it is not
a good idea to mess around with hormones unless there is a very good
reason to do so." The outcome of the conference was an
endorsement of that statement.
The conference was organized by
href="http://med.stanford.edu/profiles/frdActionServlet?choiceId=printerprofile&fid=4676">Linda
C. Giudice, MD, PhD, Professor and Chair at the
href="http://obgyn-nw.ucsf.edu/page.cfm?id=268">Department of
Obstetrics, Gynecology and Reproductive Sciences at UCSF; and by
href="http://healthpolicy.stanford.edu/people/philiprlee/">Philip R.
Lee, MD, PhD, who is a Consulting Professor for the Stanford
Program in Human Biology, and Chair of the
href="http://www.healthandenvironment.org/about/mission">Collaborative
on Health and the Environment.
I wasn't at the conference, but there is an article in the Oakland
Tribune that provides a glimpse of what was discussed:
href="http://www.insidebayarea.com/oaklandtribune/localnews/ci_5156161">Scientists
expose body toxin risks
Synthetic chemicals may affect two generations' ability to
have children
By Douglas Fischer, staff writer
02/04/2007
SAN FRANCISCO -- Your ability to reproduce -- and the health
of your child and even your child's children -- hinges on an exquisitely
timed series of chemical reactions controlled by infinitesimally tiny
amounts of hormones.
You scramble those reactions at your peril, in other words, and last
week hundreds of researchers gathered at the University of California,
San Francisco, warned society may be doing exactly that with synthetic
chemicals.
The chemicals, known as endocrine disruptors, are found everywhere in
our environment: food, lotions, shampoos, baby bottles, toys,
appliances, even casings for medicines. They mimic hormones at levels
scientists only recently have been able to measure, and some are active
at concentrations of a part-per-trillion or less...
...Most worrisome to scientists: In many cases, the effect of such
pollution on our bodies remains as unknown and mysterious as the
processes they potentially disrupt.
"In the absence of concrete data for many of these chemicals, the
precautionary principle should be exercised," said Dr. Linda Giudice,
chairwoman of obstetrics, gynecology and reproductive sciences at UCSF
and the organizer of the reproductive health conference that brought
500 scientists, clinicians and community activists together...
...The science of endocrine disruptors is still controversial. The
effects in humans are uncertain. Government panels assessing the
evidence for many compounds repeatedly have found no need for concern.
But scientists say disturbing gaps remain in our knowledge.
To keep this in perspective, it is important to realize that it is easy
to became fearful of the unknown. Ancient maps often were
decorated with pictures of monsters.
Ancient map captures ocean front
By Julianna Kettlewell
BBC News Online science staff
5 May, 2004
An ancient map of the North Atlantic - which features sea snakes and
other dreadful monsters - may have boasted surprisingly advanced
information.
The Carta Marina - published in 1539 - depicts elaborate sea swirls
which, say researchers, closely match a giant ocean front shown in
satellite images.
If correct, it means the Swedish cartographer Olaus Magnus may have
been the first to map such an ocean feature.
Today, researchers studying endocrine disruptors are like the ancient
cartographers: they do have information, and what information they have
is accurate. It's just that what they are studying is inherently
difficult to study, given the limitations of contemporary
technology. The cartographers struggled with great geographic
distances. The modern researcher has to study things that are
extremely small, and have tiny effects, but the effects can accrue over
long stretches of time.
The Carta Marina no doubt was made, in part, through the use of an
astrolabe. (The sextant was invented by Isaac Newton, but he had not
been born yet.)
Modern research tools are more advanced than the astrolabe, but still
have limitations. When it comes to the study of endocrine
disruptors, though, the greatest limitation is not the
technology. The big limitation is that you can't do randomized
controlled trials on humans with putative endocrine disruptors.
We can do tests on animals, but the results do not necessarily indicate
anything about effects on humans.
There have been examples of people getting carried away with the fear
of the poorly-charted area of endocrine disruptors, as
href="http://scienceblogs.com/pharyngula/2006/12/satans_perfect_food_tofu.php">noted
a while back on Pharyngula. We don't want to be excessively
fearful, but we don't want to be negligent, either. It's hard for
the consumer to know how to evaluate the potential risks, and to strike
the right balance between prudence and excessive caution.
Use your favorite search engine to search for "soy thyroid" (without
the quotes) to get an idea of the massive amount of information that is
available on these kinds of topics. Much of it can be misleading,
especially if you only read one or two items.
What this does suggest is that we might be wise to limit our exposure
to unnecessary chemicals, especially during pregnancy and the early
developmental years. The NIH has a simple publication (
href="http://www.niehs.nih.gov/oc/factsheets/pregnant/home.htm">NIH
Publication #01-4966) that outlines the things to avoid, that would
cause the greatest risks. It doesn't deal specifically with
endocrine disruptors, but the concepts are the same. The idea to
to avoid the big risks, try to stay informed, and don't be too worried
about the small risks. Let the scientists do their work, maintain
support for generous funding of basic and applied research, and wait
for scientists to figure out what we really need to worry about.
Remember there is no risk-free path; there is
href="http://www.pbs.org/wgbh/evolution/library/10/4/l_104_07.html">some
evidence that raising a child in a very clean environment can pose
certain risks, too (the "
href="http://en.wikipedia.org/wiki/Hygiene_hypothesis">hygiene
hypothesis").
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Are LOACs appropriate for detection and quantification of serum concentrations of hormones or is there to much structural homology between some hormones, such as testosterone and androsterone or activin and inhibin for it to be effective? I'm just curious as to whether they would work. Doubtless, they're expensive, but given the pulsatile nature of most serum hormones, it seems to me that they might be effective in making temporal studies of hormone secretion.
I'm not the best person to ask, but I'll tell you what I know. I think labs-on-a-chip are better for sorting and detecting cells and cell types; and detection, but not quantification, of molecules. It is a very rapidly developing field, though, and it is not something I follow closely.