Why are “endocrine disruptors” a concern?

6 03 2015

 

In 2012, Greenpeace analyzed a total of 141 items of clothing, and found high levels of phthalates in four of the garments and NPE’s in 89 garments – in quantities as high as 1,000 ppm – as well as a variety of other toxic chemicals. Phthalates and NPE’s are among the chemicals known as “endocrine disruptors” (EDCs) – chemicals which are used often and in vast quantities in textile processing.

The endocrine system is the exquisitely balanced system of glands and hormones that regulates such vital functions as body growth (including the development of the brain and nervous system), response to stress, sexual development and behavior, production and utilization of insulin, rate of metabolism, intelligence and behavior, and the ability to reproduce. Hormones are chemicals such as insulin, thyroxin, estrogen, and testosterone that interact with specific target cells.  The endocrine system uses these chemicals to send messages to the cells – similar to the nervous system sending electrical messages to control and coordinate the body.

Diabetes, a condition in which the body does not properly process glucose, is an endocrine disease, as is hypoglycemia and thyroid cancer. According to the Centers for Disease Control (CDC), 29.1 million people have diabetes.[1] The three types of diabetes are a good illustration of the two main ways that something can “go wrong” with hormonal control in our bodies. In type I diabetes, his/her pancreas is unable to make insulin. Without insulin, the liver never “gets the message” to take glucose out of the bloodstream, so blood glucose remains too high, while the stores of glucagon in the liver are too low. In type II diabetes, the person’s pancreas is making enough insulin, but the insulin receptor sites on the liver cells are “broken” (possibly due to genetic factors, possibly do to “overuse”) and cannot “get the message.” Because the liver is unable to receive the instructions (despite the presence of lots of insulin), it does not take glucose out of the bloodstream, so blood glucose remains too high, while the stores of glucagon in the liver are too low. In type III diabetes (AKA Alzheimer’s Disease)[2], it is the neurons in the brain, specifically, which “don’t get the message,” (though it sounds like researchers have yet to determine whether that’s due to lack of the brain-produced insulin upon which they depend, or whether that’s due to receptors on the neurons that either are or become “broken”) and thus, cannot take in the sugar that they need, with the result that, without an alternative fuel source such as medium-chain triglycerides, the neurons will starve.

endocrine disruptor

Over the past 60 years, a growing number of EDC chemicals have been used in the production of almost everything we purchase. They have become a part of our indoor environment, found in cosmetics, cleaning compounds, baby and children’s toys, food storage containers, furniture and carpets, computers, phones, and appliances. We encounter them as plastics and resins every day in our cars, trucks, planes, trains, sporting goods, outdoor equipment, medical equipment, dental sealants, and pharmaceuticals. Without fire retardants we would not be using our computers or lighting our homes. Instead of steel and wood, plastics and resins are now being used to build homes and offices, schools, etc. A large portion of pesticides are endocrine disruptors.

What this constant everyday low-dose exposure means in terms of public health is just beginning to be explored by the academic community. We have learned over time that many chemical substances can cause a range of adverse health problems, including death, cancer, birth defects, and delays in development of cognitive functions. For instance, it is well established that asbestos can cause a fatal form of lung cancer, thalidomide can cause limb deformities, and breathing high concentrations of some industrial solvents can cause irreversible brain damage and death. Only relatively recently have we learned that a large number of chemicals can penetrate the womb and alter the construction and programming of a child before it is born. Through trans-generational exposure, endocrine disruptors cause adverse developmental and reproductive disorders at extremely low amounts in the womb, and often within the range of human exposure.

Recent research is giving us a new understanding of EDCs since Dr. Theo Coburn wrote Our Stolen Future.  Thanks to a computer-assisted technique called microarray profiling, scientists can examine the effects of toxins on thousands of genes at once (before they could study 100 at a time at most). They can also search for signs of chemical subversion at the molecular level, in genes and proteins. This capability means that we are beginning to understand how even small doses of certain chemicals may switch genes on and off in harmful ways during the most sensitive period of development. In a recent talk at the National Academy of Sciences, Linda Birnbaum, the head of the National Institute of Environmental Health Sciences (NIEHS) and the National Toxicology Program, called toxicogenomics—the study of how genes respond to toxins—the “breakthrough” that pushed the study of poisons beyond the “obvious things,” that is, the huge doses that led to “death or low birth weight.”

  1. Age at time of exposure is critical. There is even a new terminology to explain the consequences of exposure to EDCs: “the fetal basis of adult disease”, which means that the maternal and external environment, coupled with an individual’s genes, determine the propensity of that individual to develop disease or dysfunction later in life.  This theory, known as the “developmental origins of health and disease,” or DOHad, has blossomed into an emerging new field. DOHad paints a picture of almost unimaginably impressionable bodies, responsive to biologically active chemicals until the third generation.
  2. The developmental basis of adult disease also has implicit in its name the concept that there is a lag between the time of exposure and the manifestation of a disorder. In other words, the consequences of exposure may not be apparent early in life.
  3. Exposures don’t happen alone – other pollutants are often involved, which may have additive or synergistic effects.[3]
  4. Even infinitesimally low levels of exposure – or any level of exposure at all – may cause endocrine or reproductive abnormalities, particularly if exposure occurs during a critical developmental window[4]. Surprisingly, low doses may even exert more potent effects than higher doses.

    Carol Kwiatkowski, director of TEDX

    Carol Kwiatkowski, director of TEDX

  5. EDCs may affect not only the exposed individual but also the children and subsequent generations.[5]

TEDX (The Endocrine Disruption Exchange, Inc.) is the only organization that focuses primarily on the human health and environmental problems caused by low-dose and/or ambient exposure to endocrine disrupting chemicals.

TEDX’s work is prevention driven, and it is the only environmental organization that focuses on the problems associated with endocrine disruption attributable to synthetic chemicals found in the general environment. While there are other national, international, and local organizations that address the public health and environmental consequences of toxic chemicals in the environment, none of them expressly emphasize endocrine disruption. By mainly focusing on substances in the environment that interfere with development and function throughout all life stages, TEDX has one of the most complete databases in the world on this topic, available for those concerned about public health and environmental quality. This database was developed because traditional toxicological protocols have used high doses on fully developed tissues and individuals that heretofore missed the consequences of chemical substances on developing tissues.

TEDX is unique because it focuses on the damaging activity of chemicals on biological systems from an entirely new approach. This new approach focuses on the effects of very low and ambient levels of exposure on developing tissue and resulting function before an individual is born, which can lead to irreversible, chronic disorders expressed at any time throughout the individual’s life.

Endocrine disruption takes into consideration the vulnerability of every individual in the population during their most vulnerable life stages. By providing this unique perspective on the actions of endocrine disruptors, TEDX fills in the very large gap in public health protection that traditional toxicology and government regulatory agencies do not fill. Drawing upon its computerized databases on endocrine disruption and coordination with researchers in the field of endocrine disruption, TEDX provides the very latest summaries of the state of knowledge and its meaning for human health and the environment.

 As the TEDX website states:   “The human health consequences of endocrine disruption are dire. Yet, no chemical has been regulated in the U.S. to date because of its endocrine disrupting effects – and no chemical in use has been thoroughly tested for its endocrine disrupting effects.. The U.S. government has failed to respond to the evolving science of endocrine disruption. While much remains to be learned in regard to the nature and extent of the impact of endocrine disruptors on human health, enough is known now to assume a precautionary approach should be taken. TEDX provides concerned persons and organizations with a science-based foundation for individuals to act and promote responsive public policy-making. Moreover, as federal government resources devoted to research on endocrine disruption have diminished due to budget cuts, TEDX must assume an even more prominent role in developing and disseminating information on the human and environmental impacts of endocrine disruption.”

To date, no chemical in use has been thoroughly tested for its endocrine disrupting effects. Traditional toxicological testing protocols were not designed to test for endocrine disruption and to test at ambient or low exposure levels.

 

 

[1] http://www.cdc.gov/diabetes/pubs/statsreport14/national-diabetes-report-web.pdf

[2] De la Monte, Suzanne, and Wands, Jack R., “Alzheimer’s Disease is Tyupe 3 Diabetes – Evidence Reviewed”, J. Diabetes Sci Technol 2008 Nov; 2(6): 1101-1113

[3] Crews D, Putz O, Thomas P, Hayes T, Howdeshell K 2003 Animal models for the study of the effects of mixtures, low doses, and the embryonic environment on the action of endocrine disrupting chemicals. Pure and Applied Chem- istry, SCOPE/IUPAC Project Implications of Endocrine Ac- tive Substances for Humans and Wildlife 75:2305–2320

[4] Sheehan DM, Willingham EJ, Bergeron JM, Osborn CT, Crews D 1999 No threshold dose for estradiol-induced sex reversal of turtle embryos: how little is too much? Environ Health Perspect 107:155–159

[5] Anway MD, Skinner MK 2006 Epigenetic transgenera- tional actions of endocrine disruptors. Endocrinology 147: S43–S49

 

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