In this week's blog, I want to take a closer look at the relationship cortisol has with some other major players in the hormone world. Specifically, I'm going to delve into how stress, and it's end product cortisol, can create abnormal function of the thyroid gland, accelerating deterioration and aging.
The thyroid is a gland in the front of your neck that has two lobes, each of which is set slightly below and on the side of your larynx (voice box). The major hormone it secretes is thyroxine, or T4. It does this in response to a cascade of hormones that starts in the hypothalamus (the master controller), a part of the brain that is constantly sampling the blood for levels of everything from glucose and hormone levels to temperature and pressure. When the hypothalamus senses low levels of thyroid hormones, it secretes Thyroid Releasing Factor (TRF), which travels a short distance to the pituitary gland. The pituitary, located as deep inside the skull as you can get, then secretes Thyroid Stimulating Hormone (TSH). Once TSH is released, it flows through the blood to the thyroid gland, and stimulates the release of T4.
In order for the thyroid to make T4, it needs certain raw materials, specifically iodine, selenium, vitamin E, tyrosine (a part of protein) and just the right amount of cortisol. Providing it has all of these in the right amounts, it sends T4 out into the body. Once there, T4 , really a pro-hormone, is converted to its active form, triiodothyronine (T3). This step also needs certain factors present, namely selenium, vitamin E, and just the right amount of cortisol.
Every cell in your body has receptors on its surface for T3, which, once activated, have a profound effect on your physiology. In a nutshell, when T3 stimulates those receptors, it speeds up your metabolic rate, or increases how much energy your body will burn at rest. By doing this, it tells all of your cells how quickly to do their work. With enough T3, your body has the ability to do its work at a normal pace and things work well.
With too much T3 (hyperthyroidism), the body is supercharged, and we end up seeing symptoms like anxiety, fast heart rate, high blood pressure, rapid breathing, elevated temperature, difficulty sleeping, bulging eyes, thin sweaty skin, tremors, fatigue, weight loss, increased appetite, weakness, loss of menstrual cycle, and frequent bowel movements.
Lack of T3 causes the opposite effects, and is termed hypothyroidism. With this condition, we see symptoms like hoarse voice, puffiness around the eyes, cold intolerance, dry hair that falls out easily, coarse dry skin, weight gain, fatigue, lethargy, forgetfulness, slow heart rate, constipation, nerve disturbances like carpal tunnel syndrome, heavy menstrual flow, and anemia. When you look at the symptoms of hypothyroidism as a whole, with a few exceptions, it looks very much like what we see in an aging person. In fact, there are some who theorize that aging is a process of slowly developing hypothyroidism, and if we kept the thyroid function normal, we would see a slowing of this process. While this is yet to be fully proven, it does show some interesting possibilities, especially since thyroid function can be influences quickly and relatively easily with proper diet and lifestyle changes added to targeted nutrition.
Frank hypothyroidism is rarely caused by stress and cortisol, but there is a condition termed Euthyroid Sick Syndrome (ESS), that can be. In this condition, we see patients having many of the symptoms of hypothyroidism, but when we look at their lab results, they look normal. One of the issues with this condition is that in medicine, rarely do we look past the TSH test. I believe this is paramount to profession wide malpractice, but it is all that is usually looked at. In fact, this isn't even looking at thyroid function at all, but instead is peering at the pituitary's function. TSH is often normal in patients, yet when I look closer at their complete thyroid panel, there are significant abnormalities.
In the patient whose body is functioning normally and has just the right amount of cortisol, the body will secrete the right amount of T4 and activate it to T3. In those with high or low cortisol levels or those lacking adequate vitamin E or selenium, we see a different picture. While some T4 will still be made, the body has a different pathway to make T3, and we end up with a different product. Instead of activating T4 to T3, we get what is called reverse T3 (rT3). It looks exactly like regular T3, but it is a mirror image. It's no different than looking at your right hand compared to your left. They normally have identical numbers of fingers and a thumb, but the thumb is on the opposite side. If you put your left hand into a left handed glove, it works fine. If instead, you put the right hand into that left handed glove, things don't work so well. This is the case with rT3.
When the body has been exposed to high stress levels for extended periods, the body starts making less T4, and what T4 is made is then converted mostly to rT3, which changes how the body functions. Without T3, the cells start going into a hypothyroid state, and we get sluggish metabolism. With elevated rT3, we get these results exaggerated, since not only is the receptor blocked so T3 can't get there, but rT3 also shuts the receptor off, and can get stuck, just like a right hand in a left handed glove. In this case, the body will recognize it has plenty of thyroid hormone, since there is plenty, but it's too much rT3, and things are shutting down, yet the TSH will be normal or even low. According to medicine, the patient is fine, yet the reality is that they are far from fine. Their body is functioning as someone who is hypothyroid, yet it is unrecognized.
I see patients who exhibit ESS on a regular basis, and it is a fairly straightforward condition to treat. By doing a full thyroid lab workup, it is not that difficult to differentiate. Once found, I can counsel the patient on avoiding things that will aggravate the condition, and we can target nutritional therapy to not only help the body make more T3 instead of rT3, but also help the adrenals function better and secrete the proper amount of cortisol. Even frank hypothyroidism can be treated nutritionally, reducing the need for synthetic medications, all of which have some unwanted effects.
As we continue this discussion on stress in future blogs, you'll see how stress affects all of the systems in our bodies, and we cannot be healthy if we are not addressing how our body reacts to stress. Stress has a huge impact on thyroid function, and your body will deteriorate quickly and steadily if you ignore it. For a long healthy life, stress must be addressed, its impact on the thyroid should be assessed, and appropriate therapies added to help regain its optimal function.
Look for future blogs that will give more information and insights into improving your health with natural health care. You can also visit my website, like me on Facebook, follow me on Twitter, or listen to my radio show.
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