Our Stolen Futurea book by Theo Colborn, Dianne Dumanoski, and John Peterson Myers
 
 

 

 

Myths... versus reality.

 
  One of the unfortunate aspects of the public debate about endocrine disruption has been a repeating pattern of distortion of scientific findings by various representatives of chemical interests.  A core of these have been repeated in many circumstances--op-eds, articles in venues like the Wall Street Journal and Forbes Magazine or less widely-circulated trade magazines.  They sound plausible, at first glance, unless you are familiar with the underlying science.   
   
 
Myth:
that endocrine disruption is of no concern to human health because the chemicals implicated are weak in comparison to natural estrogen
Reality:

This myth is wrong for several reasons, but it begins (as do many initially-credible myths) with a grain of truth.

Estrogenic substances like bisphenol A, DDT, nonylphenol, etc., are thousands of times weaker than the human estrogen estradiol at binding with estrogen receptors within the nucleus, the 'nuclear hormone receptors.' That's the grain of truth.

But it's misleading for two reasons. First, natural chemicals called 'serum binding proteins' circulate in the bloodstream and bind with estradiol. As a result, only a very small portion of estradiol in serum is available for binding with the nuclear hormone receptors. These serum binding proteins are much less effecting at soaking up circulating xenoestrogens like BPA. Hence even if xenoestrogens are weaker, they are much more available. Calculations show that if you take into account both the relative weakness of the xenoestrogens and their much greater bioavailability, even at relatively low doses they should have biological effects. And experiments with animals prove that they do.

The second reason is that estrogens also bind with receptors on the cell membrane surface. When they do, they initiate signaling pathways that control a number of important physiological and genetic pathways. It turns out that some xenoestrogens are just as powerful as estradiol at binding with these membrane receptors.

Hence to call them 'weak estrogens' is factually incorrect. From the perspective of membrane receptors, they are quite powerful. This research detects impacts at doses as low as parts per trillion.

The third reason why this myth is misleading is that estrogenicity is just one part of endocrine disruption. Contaminants also interfere with thyroid, testosterone, and many other hormones.

Myth: that DDT hasn't been linked to human harm
Reality:

DDT does not appear to cause immediate toxic effects in people, at least at the levels likely to be encountered today in malaria vector control programs.

A study published in July 2001 by scientists from the US Centers for Disease Control and the National Institute of Environmental Health Sciences, however, clearly repudiates any notion that DDT is without human health risk.

This research, published in The Lancet, reveals a strong link between DDT exposure and the likelihood of pre-term birth: the greater a mother's exposure, the more likely it is that her infant will be born prematurely. Premature birth itself is linked to a wide array of health problems later in life. And the pattern found by the scientists was so strong that they concluded there had been an epidemic of pre-term birth in the US due to DDT exposure during the decades of heavy DDT application. More...

Another study, by scientists at the National Institute of Environmental Health Sciences, indicates that DDT's effect on infant mortality, both by increasing preterm birth and by decreasing the length of time that mothers breast feed, is very substantial. More...

A gaggle of conservative ideologues nonetheless pushes for DDT use even in the US. Example... In fact, the NY Times published an op-ed calling for DDT use in the US in August 2003.

 

Myth:
that studies now prove that compounds like DDT and PCBs are not risk factors for breast cancer.
Reality:

Several recent studies indicate there is no association between PCBs and DDE (a persistent break-down product of DDT) levels in adult women and their risk of breast cancer.

  • None overcome severe obstacles that epidemiology faces when confronting mixtures.
  • None address the question of whether developmental exposure (fetal or pubertal) increases breast cancer risk. More...
  • None incorporated information about genetic susceptibility (see below)

These studies, moreover, say nothing about whether weakly estrogenic contaminants cause breast cancer.

Other studies reveal that a less studied xenoestrogen—dieldrin—is a risk factor for breast cancer and another recent study reinforces concerns about dioxin. 

In late 2004, scientists reported that a strong association between PCBs and breast cancer risk in women with a specific variant of an allele whose gene product is important to PCB detoxification. This discovery is especially insightful because it was the third study of this population of women. The first two found no association. Only the third, with information about genetic type, was able to detect the strong association. It had been masked by mixing women with different susceptibilities in the same analysis.

Myth:
that arsenic treated wood becomes safe for children as it ages.
Reality:

New research by the Environmental Working Group and the University of North Carolina demonstrates that old arsenic-treated wood structures are as dangerous as new ones. Arsenic continues to leach out of this wood for many years. And what had been thought to be protective—coating it with sealant— only works for 6 months or less. Some of the soil around decks and playgrounds where arsenic treated wood has been used actually is so contaminated that it qualifies for SuperFund. More...

 
Myth:
Chemicals used in products sold to consumers have been tested and found safe from health effects.
Reality:

Wrong. Most chemicals in modern use have simply not been tested for their impacts on human health, even very basic effects. If tests have been carried out, they usually are far too simplistic to anticipate many important health effects. More...

Myth:
Our Stolen Future is nothing but hypothesis masquerading as fact and it risks generating public hysteria over exposure to chemicals whose risks may be uncertain.
Reality: In the book and on this web site we carefully distinguish between what is known and what is plausible but uncertain. One of the book's main conclusions is a call for new scientific research to answer unresolved questions. And one of the most gratifying impacts of the book has been to contribute to interest (and funding) for that new research, the results of which are building rapidly. These new results are providing dramatic support for the issues raised in Our Stolen Future.
Myth:
that risk assessment standards based upon tests using adult human subjects will provide safe guidelines for exposure.
Reality: Children are not little adults.  Tests on adults give few  insights into the health risks created by pesticide exposure for the fetus and for children, who are usually far more sensitive to contamination than adults.  More...
Myth:
that the final scientific word on frog deformities proves they are a result of natural processes, not human activity.
Reality: The latest research on frog deformities implicates a combination of natural and human causes. Parasitic infections clearly can induce deformities, although they appear to be absent in some cases. Agricultural fertilizers create conditions in ponds that allow the parasites to become more numerous. And pesticides, undermine the frog's capacity to resist infection. Thus deformities are more common where both agricultural chemicals and parasites co-occur.  More...

 
 
Myth:
that the withdrawal of a paper by scientists at Tulane University on synergistic interactions among estrogenic pesticides means that there is no scientific basis for concern about endocrine disruption.
Reality: There are many other examples of synergistic interactions in the scientific literature.  And health risks of endocrine disrupting chemicals are of concern with or without synergistic interactions among chemicals. This doesn't stop chemical industry advocates from issuing scientifically ludicrous claims.
More on synergy and the importance of mixtures...
 
 
Myth:
that humans are exposed to so many natural plant estrogens that we needn't worry about synthetic hormone disruptors.
Reality: Both phytoestrogens and xenobiotic estrogens can can cause harm.   More...
 
 
Myth:
that new studies of human sperm count prove there has been no change.
Reality: Sperm count has clearly fallen in some geographic areas, and not in others.  More...
 
 
Myth:
that no one has been affected.
Reality: Studies demonstrate that people have been affected by endocrine disruption.  More...
 
 
Myth:
that industry's failure to replicate work on by Fred vom Saal on low level effects of bisphenol A invalidate that research.
Reality: Industry's failure here tells more about the incompetency of their attempts than the value of vom Saal's research. New analysis goes further, indicating a strong bias in industry-funded studies against finding an effect of low-dose bisphenol A. Moreover, vom Saal's research has now been confirmed by separate laboratories. More...
 

 

 

 

 

OSF Home
 About this website
Newest
Book Basics
  Synopsis & excerpts
  The bottom line
  Key points
  The big challenge
  Chemicals implicated
  The controversy
  Recommendations
New Science
  Broad trends
  Basic mechanisms
  Brain & behavior
  Disease resistance
  Human impacts
  Low dose effects
  Mixtures and synergy
  Ubiquity of exposure
  Natural vs. synthetic
  New exposures
  Reproduction
  Wildlife impacts
Recent Important    Results
Consensus
News/Opinion
Myths vs. Reality
Useful Links
Important Events
Important Books
Other Sources
Other Languages
About the Authors
 

Talk to us: email