A Primer on the Thyroid

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The thyroid is part of a network of glands known as the endocrine system. The word “endocrine” refers specifically to glands that release hormones or other products directly into the bloodstream. These hormones are able to move throughout the body, effecting physiologic change at their intended destinations. Much like a finely crafted Swiss watch, the glands and hormones of the endocrine system help our bodies keep perfect time and remain healthy.

Early in the twentieth century, researchers knew that the hormones produced by the endocrine glands conferred a profound effect on the human body. Essentially, every organ, tissue, system and subsequent physiological reaction throughout the body was under their influence. In 1922, Dr. Henry Harrower published an extensive eighty-page monograph detailing the function and interrelations seen within the endocrine system. Prior to Dr. Harrower’s publication, scientists of the day had only suspicions about how the thyroid functioned, so his observations provided a cohesive report that garnered much attention from the medical community.

One of the most controversial and largely unaccepted observations Harrower made concerned the dynamic interplay between the glands. He believed that if one gland was dysfunctional, the rest of the endocrine system would be in a state of disequilibrium, thereby causing physical dysfunction. Harrower stated, “All [the endocrine glands] are so closely bound to each other that a disturbance in one will throw out of gear or out of action all of the others.”

Of all of the endocrine glands, the thyroid gets blamed for most of the dysfunctions we see today. In most cases, the thyroid is merely an innocent bystander, part of a larger system that has become dysfunctional. The presenting symptoms may point to the thyroid, but they can just as easily point to an adrenal insufficiency, blood sugar dysregulation or ovarian dysfunction. If you visit your doctor complaining of fatigue, anxiety, excess weight, infertility and constipation you’ll most likely walk out with a prescription for thyroid hormone replacement without any consideration of the real underlying issues. Sadly, in most cases, the thyroid is not the actual problem.

THE ENDOCRINE TRIANGLE
There are four primary endocrine glands: the adrenals, gonads (ovaries/testes), thyroid and pituitary. Although each of their respective hormones has unique roles in the body, the adrenals, gonads and thyroid are highly dependent on one another. Receiving its orders from the hypothalamus, the pituitary gland is the conductor or orchestrator of the glands, instructing them when action needs to be taken (see The Endocrine Triangle below). Its chief function is to link the hypothalamus and the nervous system to the rest of the body. The pituitary is on constant alert, monitoring the body and trying to maintain balance and homeostasis.

One of the hormones produced by the pituitary is known as thyroid-stimulating hormone (TSH). As the name implies, TSH signals the thyroid to produce more thyroid hormone, namely, T4 (thyroxine) and T3 (triiodothyronine). When thyroid hormone levels begin to fall, the pituitary is alerted and promptly sends a signal to the thyroid, asking for more thyroid hormone. This is known as a negative feedback loop.

Although TSH is most commonly known as the “thyroid hormone,” it really isn’t a thyroid hormone at all. It is, in fact, a pituitary hormone, and as such, should never be used as a sole indicator of thyroid health. There are a number of other, more effective markers that practitioners can and should use when evaluating the thyroid. But before examining those, it is important to understand how the thyroid works and why these markers will be useful in conducting effective evaluations.

THYROID INNER WORKINGS
The thyroid gland contains thousands of spherical structures known as follicles. Each of these follicles contains a reservoir of thyroid hormones, much like a swimming pool contains water. This readily available supply ensures that there is always sufficient hormone availability when TSH sends the signal, via the pituitary, that more hormones are needed.

The predominant thyroid hormone is T4. It is made up of four molecules of iodine and comprises 95 percent of the hormone produced by the thyroid. It is largely inactive and requires additional steps to be converted into the active hormone, T3. Because the thyroid requires so much iodine, it will hoard as much as possible, ensuring there is an adequate supply for continued production.

T3 is the star player of the thyroid hormone family. Although very little—less than 5 percent—is actually produced in the thyroid, T3 is responsible for most of the benefits associated with optimal thyroid health. Instead of four iodine molecules (as seen in T4), there are only three. The extra iodine molecule is cleaved off during the conversion process from T4 to T3 in either the liver, gut or peripheral tissues. Without this crucial step, adequate T3 will not be available to the cells to help stimulate the functions of growth, reproduction and metabolism.

TRIP WIRES
As with any other system in the body, there are particular triggers or events that can cause dysfunction to occur; not surprisingly, the thyroid is no exception. The gears and inner workings of the thyroid gland are sensitive to a number of external influences, all of which have the potential to prevent it from properly functioning. Lack of adequate nutrients is one such trigger.

Iodine, for example, is such an important part of our health that adequate dietary intake is crucial for optimal health. In order for iodine to be used to create thyroid hormones and have a positive impact on other body tissues, certain nutrients need to be readily available to facilitate its action. These include vitamins A, B, C and D; fatty acids; iron; magnesium; and, most importantly, selenium. When these important nutrients are missing, iodine cannot be adequately utilized, and the result is a decrease in T4 and/or T3.

In addition to raw nutrient deficiencies, there are other factors that can interfere with thyroid hormone production and usage. These can include excessive intake of cruciferous vegetables (such as cabbage, Brussels sprouts, broccoli, cauliflower and kale); consumption of soy foods; chemical pollutants including polychlorinated bisphenols (PCBs), persistent organic pollutants (POPs), phthalates, flame retardants and dioxins; and halogen exposure (bromine, chlorine and fluorine). Each of these has been shown to negatively impact the thyroid hormones’ abilities to reach their intended destination and do their job at the cellular level. These types of chemical interferences can cause symptoms pointing to obvious thyroid dysfunction, yet blood tests can appear perfectly normal.

CONVERTING T4 TO T3
The process of converting T4 to T3 is quite complex and occurs in sites outside the thyroid gland. For this conversion to take place, it is especially important that the key nutrients mentioned earlier be present. The two primary sites where conversion takes place are the liver (60 percent) and the gut (20 percent). The remaining T4-to-T3 conversion occurs in various sites in the body referred to as “peripheral tissues.” This symphony of conversions provides readily available thyroid hormones throughout the body.

Conversion can be hampered by impaired nutritional status, liver dysfunction, insufficient digestion or a disordered gut. Still, there is one dysfunction that trumps them all: stress and the prolonged production of cortisol.

THE ROLE OF THE ADRENAL GLANDS
The adrenal glands are part of the endocrine triangle and strongly influence the function of the thyroid. When life stress is either prolonged or excessive, the adrenals release the hormone cortisol to try to keep stress under control.

Excessive amounts of cortisol can block thyroid hormone production, resulting in decreased levels of T3 (triiodothyronine) in the bloodstream. When this occurs, the pituitary gets the signal that there isn’t enough hormone and triggers the thyroid to produce more TSH. This begins a cycle of dysfunction within the endocrine triangle, causing a wide array of symptoms coming from any or all of the glands.

Because of the close relationship between the adrenal glands and the ovaries or testes (both produce steroid hormones, which are made from cholesterol), a dysfunction in one will lead to a dysfunction in the other. Soon, hormone imbalances begin to occur, which can further impact thyroid hormone conversion and utilization downstream. Common symptoms include premenstrual syndrome (PMS), irritability or heavy bleeding in women, along with a general loss of tolerance for noise, stress or disorder in both sexes. Men can also experience decreased libido, erectile dysfunction or generalized apathy.

THE SMOKING GUN
One of the most common causes of disordered thyroid hormones is the use of or exposure to bioidentical hormones or other hormone-like substances. These can be found in prescription or over-the-counter hormones, birth control pills and IUDs or even in testosterone used by men. When used for longer than two to three months, these hormones can impair the movement or transportation and usage of thyroid hormones in the body. Furthermore, these hormones are easily transferred from one person to another, be it parent-to-child or husband-to-wife. This is commonly known as “passive transfer” and occurs most readily when hormones or hormone-containing products are applied directly to the skin. After two to three months of usage, these hormones will begin to “spill out” via sweat glands on the skin, activating passive transference to whomever gets touched.

Aside from prescription hormones, bioidentical hormones or other hormone-like substances are often found hiding in skin and body care products. Many manufacturers are keen to the fact that estrogen causes the skin to look and feel softer and more youthful. In order to keep customers coming back, they will add small amounts of estrogen or estrogen-like compounds to their products to obtain the desired effect. This type of product can be treacherous to someone dealing with a thyroid problem, because they are likely to be completely unaware of the fact that their body lotion, face cream or aftershave lotion contains hormones that interfere with the delicate rhythm of the endocrine system.

SOLUTION TO THE PROBLEM
It may sound complicated and perhaps even overwhelming at first, but ultimately, there are five key principles to consider when trying to support the thyroid. These involve supporting healthy digestion, liver function, adrenal function, diet and the gut.

1. Support digestion and breakdown of food in the stomach. This will pave the way for efficient and thorough absorption later on along the digestive tract. Support should include digestive bitters, foods and herbs to support healthy bile flow and production, and sufficient pancreatic enzymes to ensure optimal breakdown of food before it enters the middle to lower small intestine.

2. Support healthy liver function. This is an important part of healing the thyroid, given that 60 percent of T4-to-T3 conversion occurs in the liver. Herbs that help support a healthy liver include silymarin (the therapeutic component of milk thistle) and schisandra, along with cruciferous vegetables, onions and garlic.

3. Support healthy adrenal function and manage lifestyle stress. This is a foundational step that should be considered for almost everyone, regardless of whether thyroid dysfunction is present. Prolonged elevations of cortisol have a profoundly negative effect on T4-to-T3 conversion that will continue until the stressors have improved and/or the adrenal glands become more capable of managing the stress. Herbs to consider include ashwagandha, rehmannia, eleuthro, rhodiola and
Korean ginseng.

4. Maintain a diet free from processed foods and chemicals. These will not only cause nutrient depletions but can contribute to alterations in metabolism, weight gain, fatigue and increased risk of gastrointestinal disorders. Be sure to include foods rich in fiber to help improve overall gut health and regular elimination.

5. Support a healthy gut. The digestive tract, especially the large intestine, is home to billions of microbes that play a significant role in human health. It is vitally important to ensure these organisms are well cared for and are in a harmonious relationship with one another. Much like a garden, some of them can overgrow, creating a less-than-optimal environment, leading to intestinal dysbiosis or leaky gut.

PROPER TESTING
Insurance restrictions prevent many health care providers from ordering thorough blood panels to evaluate for thyroid dysfunction. The most common marker ordered is TSH which, as previously mentioned, is not actually a thyroid hormone. In order to better understand whether there is truly a dysfunction within the thyroid gland itself, the right markers must be evaluated in context with one another. Without a complete picture, a misdiagnosis is much more likely to happen, resulting in unnecessary and often unhelpful medications.

To minimize these risks, it is imperative to consider seven serum markers that can indicate and make it possible to examine suspected thyroid dysfunction: TSH, total T4, total T3, reverse T3, T3 uptake, TPO and TGB (see sidebar below).

CONCLUSIONS
Although thyroid dysfunction has many causes, it can be corrected over time with the right information and plenty of patience. Thyroid hormones may be needed in some cases, but taking time to test thoroughly and evaluate for underlying causes can make a significant difference in the intended health outcome.

Start by incorporating the five foundational tenets mentioned above, and find a practitioner who is well versed in thyroid issues. This person should be able to listen to your goals and needs, working with you rather than just talking at you.

The good news is that a possible thyroid issue doesn’t have to keep you from living your best life. Be your own advocate, ask questions and maintain a steady commitment to maximizing your health.

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SIDEBAR

SERUM MARKERS TO TEST FOR THYROID DYSFUNCTION
TSH: Although not a thyroid hormone, this pituitary hormone can provide some insight about what might be happening with the feedback between the body and the brain. This marker can vary though. It should not, therefore, be used as a concrete marker for thyroid dysfunction.

TOTAL T4: This marker provides information about how much T4 the thyroid is producing. If total T4 is on the low end of normal, it can indicate a need for iodine and/or selenium.

TOTAL T3: The reference range for this marker is much larger than T4 because of the amount converted into T3. Lower levels may indicate a need for liver and gut support in order to improve T4-to-T3 conversion.

REVERSE T3: This is a useful marker to rule out stress as a contributing factor to thyroid dysfunction. If low, consider general adrenal support and focus on improving overall liver function.

T3 UPTAKE: When elevated, this marker can indicate a possible passive exposure to testosterone. If low, consider the possibility of estrogen exposure.

TPO: One of two thyroid antibodies, this serum marker is commonly positive with the presence of Hashimoto’s thyroiditis.

TGB: This thyroid antibody is not positive as often as TPO. However, it can be significantly elevated with Graves’ Disease.

 

This article appeared in Wise Traditions in Food, Farming and the Healing Arts, the quarterly magazine of the Weston A. Price Foundation, Winter 2017.

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