#487: Our Stolen Future--Part 2
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Humans and other animals (fish, birds, reptiles, amphibians, and
mammals) all have three great internal networks that coordinate
growth, development, and behavior:
** the nervous system (brain, spinal cord, and peripheral nerves);
** the immune system (a myriad of specialized cells and tissues
that protect us against bacteria, viruses, and cancers); and
** the endocrine system, which controls and coordinates the body
by sending chemical messages (hormones) through the blood stream,
turning on and off various functions throughout the body.
The human body is more than a mere collection of 50 trillion
individual cells because our cells work together. Working
together requires coordination, which requires communication.
Nerves are just one avenue of communication--the one employed for
rapid, discrete messages, such as a quick instruction to a hand,
to move away from a hot stove. A large part of the body's
internal communication and control is carried out via the
bloodstream, where hormones and other chemical messengers move
about, carrying signals that not only govern sex and reproduction
but also coordinate organs and tissues that work together to keep
the body functioning properly.
Hormones --chemical messengers --began to be understood early in
this century. Nobel prizes were awarded for the discovery of
insulin in 1923, and for work on sex hormones in 1939. The
best-known hormones are estrogen (the main female sex hormone)
and testosterone (the main male sex hormone) but by 1987 more
than 100 hormones had been identified in humans and higher
mammals.[1]
The endocrine (hormone) system plays an important role starting
early in life's beginnings. It is the endocrine system that
controls development of the embryo. The embryo begins as a
single fertilized egg cell, which divides again and again,
creating new cells; these cells in turn "differentiate" into
different kinds of cells, thus creating a brain, eyes, fingers,
genitalia, and so forth. All of these processes are controlled
by hormones.
In 1950, researchers at Syracuse University exposed young
roosters to DDT and showed that their testicles only grew to 18
percent of normal size.[2] The researchers concluded, "These
findings suggest that DDT may exert an estrogen-like action..."
A 1963 study in the JOURNAL OF THE NATIONAL CANCER INSTITUTE
showed that cysts and cancers developed in mice treated with
estrogen as newborns. In that 1963 study, author Thelma Dunn
warned that her work showed "the vulnerability of the immature
animal to the harmful effects of exposure to a naturally
occurring hormone."[3]
The following year, in 1964, two authors writing in the JOURNAL
OF THE NATIONAL CANCER INSTITUTE reported changes in vaginal
tissues in mice after exposure to estrogen shortly after birth.
They warned, "We feel that abnormal hormonal environments during
early postnatal (and antenatal) life should not be underestimated
as to their possible contribution to abnormal changes of
neoplastic [cancer] significance later in life."[4]
These early warnings were ignored. From about 1940 onward,
roughly 1000 new chemicals were introduced into commercial
channels each year (a practice that continues today). No one
asked whether any of these chemicals might exert an estrogen-like
effect or might in some other way disrupt the chemical-messaging
system on which we all depend for health and well-being. Still
today, no one in any official capacity is asking.
Starting in the 1950s, papers began to appear in scientific
journals showing declines in wildlife populations, resulting from
exposures to certain pesticides. Reports of odd behavior began
to appear as well --pairs of female gulls (so-called "gay gulls")
sharing nests; pairs of terns (birds on the Great Lakes) failing
to sit on their eggs, neglecting to defend their nests against
predators. Alligators with penises so small they couldn't
reproduce. As time passed, hundreds of such studies accumulated
from many parts of the world.
However, it wasn't until 1991 that some scientists began to see a
pattern in these studies. In July of that year, Theo Colborn, a
biologist with the World Wildlife Fund, invited a group of 20
scientists to discuss their research. To their surprise, the
scientists all agreed that, in their individual research, they
were seeing evidence that industrial chemicals in the environment
were harming the endocrine systems of fish, birds and mammals.
They issued a consensus document, now known as the Wingspread
statement (see REHW #263, #264), which began,[5] "We are certain
of the following:
"A large number of man-made chemicals that have been released
into the environment, as well as a few natural ones, have the
potential to disrupt the endocrine system of animals, including
humans. Among these are the persistent, bioaccumulative,
organohalogen compounds that include some pesticides (fungicides,
herbicides, and insecticides) and industrial chemicals, other
synthetic products, and some metals." [An organohalogen is a
chemical that contains carbon attached to a halogen such as
chlorine; there are now 15,000 chlorine-containing organic
compounds in commercial use.
The Wingspread statement went on,
"Many wildlife populations are already affected by these
compounds. The impacts include thyroid dysfunction [impaired or
abnormal functioning] in birds and fish; decreased fertility in
birds, fish, shellfish, and mammals; decreased hatching success
in birds, fish and turtles; gross birth deformities in birds,
fish and turtles; metabolic abnormalities [impaired or abnormal
use of energy, manufacture of tissue, or handling of resulting
wastes] in birds, fish, and mammals; behavioral abnormalities in
birds; demasculinization and feminization in male fish, birds,
and mammals; defeminization and masculinization of female fish
and birds; and compromised [impaired] immune systems in birds and
mammals." This was the first time anyone had ever put two and
two together and had concluded that industrial chemicals are
interfering with hormones in wildlife and, by analogy, probably
in humans.
Since 1991, the journals have continued to swell with new studies
showing how industrial chemicals, in low concentrations, can
disrupt hormone messages.
In some instances, industrial chemicals behave like (mimic)
hormones, fooling the body into responding as if natural hormones
are present when in fact they are not, thus sending fake
messages. In other instances, industrial chemicals block
(partially or fully) the action of natural hormones, thus
interfering in the receipt of messages. In other instances,
industrial chemicals block the production of hormones, thus
preventing the sending of messages. In still other instances,
industrial chemicals interfere with the body's normal ability to
break down and eliminate hormones, thus resulting in too many
messages being present simultaneously and for too long.
No matter where you live today --whether in New York City, or on
a remote island in the Arctic Ocean, anyone willing to put up the
$2000 for testing will find more than 250 synthetic industrial
chemicals in their body.[6] DDT was first reported in human milk
in 1951 and by the early 1980s, 192 different industrial
chemicals (pesticides, solvents, etc.) were measurable in
mothers' milk.[7]
These industrial chemicals are routinely present in our tissues
at levels measured in parts per billion (or, in extreme
instances, parts per million). On the other hand,
naturally-occurring hormones often do their work at levels that
are measured in parts per trillion, one thousand times lower than
parts per billion and a million times lower that parts per
million.[8]
Furthermore, there is evidence that industrial chemicals at
exceedingly low levels can combine together to produce additive
effects. Dr. Ana Soto at Tufts University combined 10 hormone
disrupters, each at one-tenth of the dose required to produce a
minimal response; she found that the combination produced a
response.[9] Thus combinations of chemicals must be taken into
account when we try to learn how much "effective exposure" we are
getting to hormone-disrupting chemicals.
Is there any evidence that humans have been harmed? Yes, there
is. The medical profession exposed millions of women to drugs
called thalidomide and DES (diethylstilbestrol) before it was
learned that birth defects might result from such exposures. The
DES exposures, particularly, provided compelling evidence that
humans respond to hormone-disrupting chemicals the way other
mammals do. Studies of humans exposed to PCBs (a class of
hormone-disrupting industrial chemicals) shown mental and
physical stunting. (See REHW #295, #372.) (We will review
additional human evidence in future issues.)
OUR STOLEN FUTURE, Theo Colborn's new book,[5] presents evidence
and hypotheses pointing toward a variety of effects in humans:
reduced sperm count; increases in cancer of the prostate,
testicles, and female breast; diminished intelligence; reduced
capacity to pay attention; increased aggression and violence.
Are these things all proven? They are not. Are they plausible
enough and important enough to warrant thoughtful preventive
action by prudent people? They definitely are.
What lessons can we learn from all this? Many. But they will
have to wait. For the next two weeks, we will focus on the
institution that allowed our future to be stolen --indeed, made
it all but certain that our future would be stolen. Stay tuned.
--Peter Montague
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[1] Anthony W. Norman and Gerald Litwack, HORMONES (San Diego,
Ca.: Academic Press, 1987), pg. xi. And see Appendix A.
[2] H. Burlington and V.F. Lindeman, "Effects of DDT on Testes
and Secondary Sex Characters of White Leghorn Cockerels,"
Proceedings of the Society for Experimental Biology and Medicine
Vol. 74 (1950), pgs. 48-51. Even earlier, the sexual development
of mice had been disrupted by exposure to estrogen: R. Greene and
others, "Experimental Intersexuality: The Paradoxical Effects of
Estrogens on the Sexual Development of the Female Rat,"
ANATOMICAL RECORD Vol. 74 No. 4 (1939), pgs. 429-438. And: R.
Greene and others, "Experimental Intersexuality: Modification of
Sexual Development of the White Rat With a Synthetic Estrogen,"
PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE
Vol. 41 (1939), pgs. 169-170.
[3] T. Dunn and A. Green, "Cysts of the Epididymis, Cancer of the
Cervix, Granular Cell Myoblastoma, and Other Lesions After
Estrogen Injection in Newborn Mice," JOURNAL OF THE NATIONAL
CANCER INSTITUTE Vol. 31 (1963), pgs. 425-438.
[4] N. Takasugi and H. Bern, "Tissue Changes in Mice with
Persistent Vaginal Cornification Induced by Early Postnatal
Treatment With Estrogen," JOURNAL OF THE NATIONAL CANCER
INSTITUTE Vol. 33 (1964), pgs. 855-864.
[5] Theo Colborn, Dianne Dumanoski and John Peterson Myers, OUR
STOLEN FUTURE (N.Y.: Dutton, 1996), pgs. 251-260 reprints the
Wingspread statement.
[6] J.S. Stanley, [Midwest Research Institute, Kansas City, Mo.],
BROAD SCAN ANALYSIS OF HUMAN ADIPOSE TISSUE. EXECUTIVE SUMMARY.
VOLUME 1. FINAL REPORT. [EPA/560/5-86/035] (Springfield, Va:
National Technical Information Service [NTIS No. PB
87-177218/REB]. See also VOLUME II, NTIS No. PB 87-177226. And
see: Kristin Bryan and Theo Colborn, "Organochlorine Endocrine
Disruptors in Human Tissue," in Theo Colborn and Coralie Clement,
editors, CHEMICALLY-INDUCED ALTERATIONS IN SEXUAL AND FUNCTIONAL
DEVELOPMENT: THE WILDLIFE/HUMAN CONNECTION [Advances in Modern
Environmental Toxicology Vol. XXI] (Princeton, N.J.: Princeton
Scientific Publishing Co., 1992), pgs. 365-394.
[7] E.P. Laug and others, "Occurrence of DDT in Human Milk,"
ARCHIVES OF INDUSTRIAL HYGIENE Vol. 3 (1951), pgs. 245-246. And
see: Edo D. Pellizzari and others, "Purgeable Organic Compounds
in Mother's Milk." BULLETIN OF ENVIRONMENTAL CONTAMINATION AND
TOXICOLOGY Vol. 28 (1982), pgs. 322-328, reporting 192 different
industrial chemicals in samples of human milk from New Jersey,
Pennsylvania and Louisiana.
[8] In their Appendix A, Norman and Litwack, cited above in note
1, list the levels at which naturally-occurring hormones are
present in human blood. Many occur in the low parts per trillion
range.
[9] Soto's work is reported in Paul Cotton, "Environmental
Estrogenic Agents Area of Concern [sic]," JOURNAL OF THE AMERICAN
MEDICAL ASSOCIATION Vol. 271, No. 6 (February 9, 1994), pgs.
414-415.
Descriptor terms: our stolen future; theo colborn; john peterson
myers; dianne dumanoski; nervous system; immune system; endocrine
system; hormones; development; embryo; estrogen; endocrine
disrupters; wingspread statement; pesticides; thyroid disease;
infertility; wildlife; fish; birds; mammals; synergism; additive
effects; ana soto; book reviews;
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--Peter Montague, Editor
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