Home button home  About Us botton about us   Contact Us botton contact us
Fundamental Physiology, Center for Metabolic Health, Boulder, CO Dr. Gina Honeyman, Boulder, Denver CO

Subscribe to Dr. Honeyman's Newsletter

Sign Up Today!

* required


Email Marketing by VerticalResponse

Ask Dr. Honeyman

Environmental Health

Our environment includes the air we breathe, the water we drink, and the food we eat. Most people grasp the idea that air and water pollution, chemicals added to our food supplies, and other toxins can have damaging effects on our bodies. In some situations, prescription medications can be included in toxic substances that can harm health. Our thoughts and emotions factor into our individual environment and can influence our personal health.

We adapt to a changing environment and this may mean that we become stronger, more capable people as in "what doesn't kill me makes me stronger". Here is the definition of evolution: "Evolve - to come forth gradually into being; develop; undergo evolution; (Biol.) to develop by a process of evolution to a different adaptive state or condition. " ( from the Random House Webster's Unabridged Dictionary) This implies that we survive by adapting to environmental influences.

What happens if we don't adapt effectively to the chemicals that are polluting our environment? We may "devolve" and our physiology becomes less capable of maintaining necessary functions for health. As a prime example, the effects of some man-made petrochemicals are responsible for damage to the thyroid hormone systems and neurotransmitters of of many people. In 2001 I began reviewing research literature and, so far, I find agreement that the neuroendocrine systems are especially susceptible to disruption.

Neuroendocrine disruption (NED) is a general term for the effects of chemicals such as polychlorinated biphenyls (PCB's), bisphenyl (bis-A) in many plastics, DDT, and dioxins on our brains, endocrine glands (such as the thyroid), and hormone receptors. These chemicals did not exist in nature before humans manufactured them and then allowed them to filter into the air, water, soil, and food. While some of them such as PCB’s and DDT have been banned, they linger in the environment from previous use.

The thyroid system, whether we’re considering central regulating mechanisms in the brain, thyroid hormone production by the gland, transport of thyroid hormone in the blood, or utilization at the receptor level, seems to be particularly affected by NED. When I did a literature search for neuroendocrine disruption (NED), most of the research articles I found discussed the damaging effects of PCB’s on the thyroid hormone system. Since adequate thyroid hormone is so important for the optimal functioning of nearly all of the tissues in the body, a multitude of symptoms can result when there’s a breakdown in that system.

The Agency for Toxic Substances and Disease Registry (ATSDR) issued a report in 2000 that points out that we all have some level of PCB's in our bodies. There are numerous studies showing that breast milk in women across the USA has significant levels of PCB's. If you’re breast-feeding, please don’t let this information deter you - the benefits of breast-feeding far outweigh the fears of even PCB exposure. This is just an example of how pervasive these petrochemical toxins are in the environment.

An adequate amount of thyroid hormone is critical to the normal structure and chemistry of our brains. Impaired cognitive function, depression and anxiety can be linked to poor thyroid regulation of brain tissue. The production of neurotransmitters like serotonin and dopamine are affected by thyroid regulation. How many people do you know who are taking antidepressants? Particularly disturbing were the multitude of articles discussing the damaging effects of PCB’s on the brains of developing fetuses and infants through the first two years of life. How much of the ADD, ADHD, and autism that are so common in children today can be linked to poor thyroid regulation of the brain? How many children are medicated for behaviors that may be related to NED?

Endocrine-Disrupting Chemicals: An Endocrine Society Scientific Statement

by Diamanti-Kandarakis E et al. 2009 Endocrine-Disrupting Chemicals: An Endocrine Society Scientific Statement. Endocrine Reviews 30(4)293-342.   http://www.endo-society.org/journals/scientificstatements/                                  

In June, 2009, The Endocrine Society issued this report describing the many ways that neuroendocrine disruption from pervasive environmental chemicals such as PCBs, bisphenol-A (BPA), and dioxins in the environment cause impaired thyroid regulation, cancers, abnormalities of the reproductive system, diabetes, obesity, cardiovascular disease, neurotransmitter imbalances, ADD and ADHD. (Click here for the report.)

This information is not new; research articles have been published for decades describing the damaging effects of chemicals such as PCBs on the thyroid and other systems of the body. For example, all of the "moving parts"in the production and utilization of thyroid hormone are subject to impaired function from PCBs. Nine years ago the Environmental Protection Agency issued a report stating that we all have measurable levels of PCBs.

As in other realms of life, we have to acknowledge the existence of a problem before we can solve it. I see this report is an open door for the endocrinology profession to look beyond the TSH.  It provides common ground for us integrative practitioners who adopt different ideas earlier and the endocrinology profession which seems to move in geological time. Will we all agree on how to diagnose and treat clients?  It’s doubtful – put 4 doctors in a room and you’ll wind up with 5 opinions!  This 50-page report with 485 references concludes with "Recommendations for the Future". The first recommendation is"Linking basic research to clinical practice".

While this is not a new idea either, I'm encouraged by the Endocrine Society's recognition of the need. For the past thirteen years I've been looking “beyond the TSH” to help people get well. While I use a client’s symptoms and the standard thyroid lab tests as the introduction to the diagnostic process, I also use Resting Metabolic Rate (RMR) measurements and clinical judgment to find the rest of the story.  There are many of us integrative practitioners who use functional medicine testing and treatment protocols but allow the patients’ responses to treatment guide us toward the best, common sense answers for them.

Using Resting Metabolic Rate measurements for functional assessment of thyroid hormone regulation in addition to the standard thyroid-related blood tests does link basic research to clinical practice.  There are several reasons I take this position.

  • We all seem to be agreeing that neuroendocrine disruption can alter production and/or utilization of thyroid hormone. Utilization is a key concept here.
  • The standard blood tests for TSH, free T4 and free T3 give us information about the supply of thyroid hormone that is available for use, but not about utilization. 
  • As an example, neuroendocrine disruption can cause a thyroid hormone receptor to lose its affinity for the thyroid hormone that your thyroid gland produces quite well.
  • RMR will detect utilization problems at the cellular level that the standard blood tests cannot.

I propose that measuring RMR, using our clinical management skills, and educating our clients can help us all be well in spite of the damaging effects of environmental toxins.  Hopefully Planet Earth will be cleaned up but until then we can still be well. 

How do I know if NED is causing my pain, fatigue, or my brain fog?

Since I presented my concerns and information about NED in my February newsletter, I've received several letters with personal stories of exposures to a variety of harmful substances including carbon monoxide, molds, DDT, pesticides, and radioactive fallout from above-ground nuclear testing in the mid-twentieth century. Some of the stories were about extreme exposures and others were less obvious.

W.S., a man who worked as a lineman for a telephone company in the late 1960's, experienced an obvious exposure to PCB's from the oil in a ruptured telephone transformer. He had such a rapid decline in health that his workman's compensation claim was uncontested. PCB's have since been banned, but exposures continue to occur as the old transformers and electronics devices are dismantled in this country and abroad. While this nature of exposure isn't common, the insidious exposure that happens in small amounts over a longer span of time is common. According to the Agency for Toxic Substances and Disease Registry report issued in 2000, we all have measurable amounts of PCB's in our bodies.

Julia C. replied, "You got me thinking about my health problems, and how would I know if I'm having a problem due to NED? I don't feel as good as I think I should, but my doctor said that my blood tests with my yearly physical looked fine. My TSH level was in the normal range so my doctor said I don't have a thyroid problem. My doctor says that I'm just getting older (I'm 43) and I can't expect to feel as good as I did when I was younger. He said that maybe I have a "touch of fibromyalgia" because I have some vague aches, my sleep isn't great, and I fatigue easily. He prescribed an antidepressant for me because he thought I might be depressed. I didn't take it because I don't think that I am, but I know I'm not OK. Could environmental toxins be causing my problems? I grew up on a potato farm in Wisconsin and my family moved to Houston 15 years ago. The crop dusters sprayed the fields with pesticides and I can see the junk in the air here in Houston. How would I know if I have a high enough level of toxins to hurt my health?

What kind of testing do I need to see if NED is damaging my health?

You can have your "body burden" of chemicals measured and it can be valuable to know what kind of chemicals you may be storing in your body. Standard laboratory blood tests can be used to measure levels of PCB's, mercury, and many other chemicals. Hair analysis is well-suited to measure heavy metals like mercury and cadmium since it reflects long-term exposures. PCB's are stored in the liver and adipose tissue (fat) and do get excreted over time by the GI tract.

While it's interesting and potentially valuable to know this information, it won't let you know how your body is actually being effected by the chemicals. People have different abilities to compensate for the chemicals. One "dose" of PCB's may not have any effect on a strong, healthy 6-foot tall man with a normal metabolism, but could be very damaging to a toddler.

It stands to reason that a slow metabolic rate may contribute to a slower rate of excretion from these tissues. The longer the toxin remains in your body, the more damage it can do. Your body burden won't tell us if your metabolism has been impaired by them.

If you suspect that you have a problem with this, start with the usual thyroid-related blood tests including a TSH, free T4, free T3 level, and a thyroid antibody group. Tell your doctor about your symptoms, or fill out the initial evaluation forms on this web site and send them for Dr. Honeyman's review. Then, the next step is to actually measure your resting metabolic rate with a device called an indirect calorimeter.

What Can We Do About NED?

While I sincerely hope that we clean up the planet quickly, we're most likely going to be at the effect of these chemicals for the rest of my lifetime and yours. Some people seem to have the physical constitution to buffer against these contaminants and don’t seem to have any significant health impact. Others have subtle but significant problems that defy usual diagnostics. They modify their lifestyles and diets to try to be well in spite of their "mysterious illness". Some people have devastating health problems because of NED and are sidelined from full participation in their lives. How much human potential is undeveloped because of impaired thyroid regulation due to NED?

The ray of sunshine in this dismal prediction is that you can still be well, regardless of the level of impact you may currently experience. If NED has disrupted your thyroid production or utilization, metabolic rehabilitation effectively addresses the cause of the symptoms. One of the most frustrating problems for my patients has been the lack of information about thyroid disease and effective treatment by their primary care physicians and endocrinologists. My goal is to increase awareness of these problems and their solutions.

Phone: 303.413.9100
Fax: 1.888.728.3490

Copyright © 2011 Dr. Gina S. Honeyman. All rights reserved. Reproduction in whole or in part without permission is prohibited. All material provided on the Dr. Gina S. Honeyman website is offered for educational purposes only. Your participation with self-tests or sending evaluation forms for Dr. Honeyman's review do not constitute a doctor/patient relationship. Always seek the advice of your physician or other qualified health care provider before undertaking any diet, exercise, or other health program.