This is an Email that I sent to the Friends of DogtorJ on 8-16-07 after reading an article on Yahoo Health concerning common household chemicals and their possible role in the development of hyperthyroidism (*Graves Disease) in the cat. My response covers many of the areas of medicine that I have been studying over the past 7 years that are related to immune-mediated diseases and cancer. The news article served as a great spring-board into those topics.
A Grave’s* Situation
The following is an interesting article for a number of reasons. It discusses the role of a common group of household chemicals (PBDEs) in the development of hyperthyroidism (*Graves Disease) in cats and humans.
Now, most of you know that my passion has become trying to sort out the true origin of the illnesses that affect us and our pets. Part of that process has been trying to distinguish between “causes” and “triggers” (contributing factors). In order to call something a true “cause”, we have to be prepared to explain why it does not cause the problem in all individuals or species as well as give explanations for why these “causes” take so long to show up in that individual.
Case in point. Why don’t these chemicals cause the same problem in the dog? Personally, I think that is a great question. In veterinary medicine, we now see hyperthyroidism in the cat on a regular basis. As the article points out, before the late 70’s it was a rare, even unheard of, disorder. But I now routinely palpate the neck of every cat over 8 years, especially those losing weight unexpectedly. What changed? The article makes a point that PBDEs came into our households in abundance during the 70’s and 80’s time but so did something else: Wheat-based pets foods. It was during the 80’s that we made that tragic transition from corn-based to wheat-based pet foods and the incidence of thyroid disease in both cats and dogs has skyrocketed. A big clue is that celiac people (gluten intolerants) have staggering rates of thyroid problems, both hypothyroidism (Hashimoto’s Disease) and hyperthyroidism (Graves Disease). Add to that the known goitrogenic effect of the soy being used in a rising number of pet and human foods, and we see another explanation for the ever-increasing incidence of thyroid illness.
But here is the cool thing to see. Cats develop hyperthyroidism but rarely develop hypothyroidism. Dogs on the other hand commonly suffer from low thyroid but rarely have hyperthyroidism unless they develop the uncommon thyroid tumor. And humans experience both. Some may say “Hey, that’s just the way it is” but I think there is “gold in them hills”. Why would one species develop one and not the other?
You are well aware of my fascination with viruses and their role in nature, both the “good” things they do (e.g. adaptation) and the “bad” (e.g. their role in the development of “disease”). I now realize that in many instances, this is actually a continuum, with the warning signs/symptoms occurring during the adaptation phase and the “disease” occurring when we continue to do what we were doing that forced the viruses into the adaptive process to begin with. I love to use “autoimmune diseases” and cancer as the illustration, with the immune-mediated disorder being the process of house-cleaning that the immune system does in order to clear out all of the garbage developing in tissue (lectins, chemicals, diseased cells, mutating viruses) before that inflammation gets totally out of hand and the virus is forced to rise up and form tumors (cocoons), their ultimate adaptation. Simple enough, eh?
I like to apply “reverse engineering” to try to figure out the pathomechanisms of conditions we term “idiopathic” (unknown or undeterminable cause). First of all, I believe what researchers have said for years, that all cancer is ultimately viral. This just makes sense when we see what it takes for a cell to start dividing out of control and form a cancer. It is what some viruses do (e.g. retroviruses). That puts carcinogens in their rightful place, as “triggers” of cancer rather than “causes”. It also helps to explain why cancer does not occur in everyone exposed to a carcinogen. Thankfully, it takes more than that for the “big C” to occur. In fact, it takes a triad of elements to come together in order for us and our pets to suffer this dreaded condition. For cancer to develop, it also requires some degree of immune failure on our part. Yes, we all fighting cancer at this moment- cells that are trying to become cancer cells. But our immune systems (hopefully) is doing its appointed job of destroying those cells. But when that process fails, watch out! So, it takes a triad of components coming together in order for cancer to develop: Carcinogens, viruses, and immune incompetence. This is why I call cancer a “syndrome”.
But, the cancer is preceded by a period of inflammation in which the immune system is doing its housecleaning, desperately trying to clear out the carcinogens, lectins, mutating viruses, atypical cells, and other secondary invaders (e.g. mycoplasma/bacteria) that are taking advantage of the break in integrity of the tissue. Many have written that cancer is the “end game of immune-mediated disorders”. I agree. Cancer usually arises in areas of chronic inflammation (colon/intestine, lung, skin, lower esophagus, prostate, breast). Once we see that cancer is an adaptation of the virus, we can better grasp why it arises in those areas of chronic inflammation, especially once the immune system becomes incompetent.
But why don’t dogs develop hyperthyroidism and thyroid tumors like we see in the cat and human? Is it because they have a more competent immune system that so thoroughly destroys the thyroid tissue that nothing survives? Not likely. It is more likely that they do not have the particular virus that causes thyroid tumors. The most common group of oncogenic (cancer-forming) viruses is the retrovirus family. Perhaps the dog does not have the same virus that cats and humans have in their thyroid glands. We do see the occasional thyroid tumor in the dog but it is a relative rarity compared to the incidence of tumors in the cat and human.
Another interesting “fun fact” is that it has now been noted that cats can become hypothyroid just before they develop hyperthyroidism. Clinical hypothyroidism is another relative rarity in the cat. In fact, many texts say that it simply doesn’t exist as an entity. But this transient dip in the cat’s thyroid function just prior to developing Graves disease (or a tumor) is well-established. To me, this speaks volumes as to what is really going on in these glands. Hashimoto’s Disease in dogs and people is considered an “autoimmune” disease, in which the immune system attacks the gland and renders it unable to produce thyroid hormone. These individuals can even form antibodies to the thyroid hormone itself. But why doesn’t this occur in the cat? Why do they experience a transient drop before developing Grave’s Disease (hyperthyroidism) or a thyroid-secreting tumor. Could it be that the virus that causes the tumor is adapting to the attack? Graves Disease is considered an immune-mediated event in people and cats. Why would an immune reaction in a tissue cause it to over-function? Frankly, I love that question. I believe the answer is that it is over-functioning in the face of the immune response because of viral adaptation, with the proof being the high rate of tumor formation (also viral) in affected cats. For a while, the veterinary pathologists were having a hard time deciding whether the affected thyroid glands we were removing and submitting for analysis were undergoing benign thyroid hyperplasia (Graves) or actually developing into tumors (thyroid adenomas). I appreciate their dilemma. They were experiencing another continuum, I believe.
But the really cool thing to ponder is why dogs suffer from hypothyroidism (almost exclusively), cats develop hyperthyroidism(almost exclusively), and humans develop both extremes. Certainly, it could be due to co-factors required for one to develop over another. But all three species are exposed to the same known triggers- lectins (wheat, dairy soy), chemicals (e.g. PBDEs), and many of the same carcinogens (air, water, food additives). I think the answer lies again in which virus their body contains. There are very few viruses (that we know of) that are shared between dogs and cats that cause clinical illness. Most, but certainly not all, viruses in the animal world are species specific. Combining that fact with the little known gem that up to 45% of the genetic information in our DNA is actually viral information helps us to see why diseases run so true in certain breeds of animals but do not usually cross species. And pets do not get our human viral diseases, do they? The animals have a “pre-set fever” by possessing a body temperature well above that of humans. For a virus to jump from a human to a dog or cat would be like one going into a person who already has a fever. Viruses like subnormal body temps, not elevated ones. (Thus the partially correct idea of getting chilled leading to a viral infection). But the reverse is not true, is it?
Humans have acquired a number of diseases from animals over our history (Bird Flu, Swine Flu, Rabies, West Nile Virus, and more). Thank Goodness the current Bird flu has not made it’s trek through swine…yet…as it did back in 1918. (Swine are the key, which we will discuss in a moment.)
Could the reason why humans suffer from both forms of thyroid illness be because we acquired the necessary viruses from animals at some point in time? “Might could be”, as they say in the South. How would this happen? We know that many viruses that we acquire become latent in our body, even when they caused little to no clinical signs upon acquisition (e.g. Epstein Barr). We are exposed to countless viruses during our lifetime, many of which, again, serve important adaptive functions (while much of what we call “disease” is over-adaptation). This exposure comes through the breathing the air, drinking the water, contacting the skin, and eating our food.
It is simply fascinating to view the Mosaic food laws found in Leviticus 11 and repeated in Deuteronomy 14 as “health food laws”. The Israelites were among the healthiest people to walk the earth, at least those that followed the law. They knew nothing of bacteriology, microbiology and virology. All they knew is that if they ate a forbidden oyster or the unclean pork that they could die. We now know why. And these health food laws still apply, some even more than in the Old Testament days. Eating an oyster is like playing Russian roulette at times, isn’t it? (For those Christians who feel that these laws no longer apply, remember that what Jesus said about the law not passing away. It is the eternal consequences of violating these food laws that have changed, not the potential physical results.) Knowing that swine are so closely related genetically to humans (thus the mutation into an infectious agent to humans as the bird flu virus as it passes through pigs), we must consider what else might be in these “unclean” animals. As I like to say “God knows what’s in an oyster.” (How we went from not eating pork at all to having it be the meat of choice on Easter is a really interesting story by the way.)
It is a grave situation (literally) in which we find ourselves. Our environments are polluted, our diets are atrocious, and our lifestyles are out of whack. But as you have read many times, we can do so much about all of these things. Knowledge is power…sorta. Like other “syndromes”, there is another component that is necessary. We have to want to change. As my wise Pastor said last Sunday, we are a little crazy to spend all of our time and destroy our health trying to make as much money as we can only to ultimately spend it all on our failing health. It’s high time we took back our health, felt better, became more productive, and were less reliant on man’s health care system. It is our choice.
As always, I hope this helps,
John B. Symes, D.V.M. (“Dogtor J”)
Read- Food Intolerance- Man and Animals versus Gluten, Casein, Soy, and Corn OR How We Won the Battle of Helm’s Deep