Ah, the thyroid. Such a little gland with such a big impact on our bodies! The thyroid sits at the base of the neck and produces thyroid hormones that play a crucial role in the regulation of metabolism (plus several other metabolic processes… don’t worry, we’ll get there!). Thyroid hormones are involved in every single cell in the body. For as important as it is, the thyroid sure can be temperamental, huh?
So why is thyroid disease so common?
I’m so glad you asked!
Let’s begin with a basic overview of the thyroid to understand how it works so that we can further dissect why it became dysregulated in the first place.
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Meet Your Thyroid— the queen bee of your bod.
(Pssst…“sciency” stuff ahead… beware!)
She is small, but she sure is mighty— and if you have thyroid issues you know this first hand. The little thyroid of yours is busy doing a lot, including masterminding your metabolism, regulating your sleep/wake cycle, puppeteering your sex hormones, controlling your heart rate and muscle contractions, regulating your menstrual cycle, body temperature, and even your immune system. With this lofty list, it’s easy to see why “just having hypothyroidism” isn’t just having hypothyroidism!
Fun fact: thyroid hormone is the ONLY hormone directly involved in EVERY. SINGLE. CELL. It’s a pretty big deal, eh?
The thyroid gland sits on the base of the neck in front of the trachea and is shaped like a butterfly. It produces hormones that are necessary to the body to maintain metabolism and support normal hormonal fluctuations. Thyroid hormones include: thyroxine (T4), triiodothyronine (T3), T2, T1, and Reverse T3.
The thyroid takes iodine that we get from foods and combines it with an amino acid, tyrosine, to make thyroid hormones. These hormones control our metabolism, growth, repair, and general development in the body.
Let’s chat about where thyroid hormone production truly begins…
THE BRAIN!
When levels of circulating thyroid hormone are too low in the body, the hypothalamus secretes Thyrotropin Releasing Hormones (TRH) which then tells the pituitary gland (a portion of the brain that acts like a thermostat), to secrete Thyroid Stimulating Hormone (TSH), which tells the thyroid to secrete more thyroid hormone. It is a built in feedback signal to prevent the body from getting deprived of thyroid hormones.
Hypothyroidism occurs when levels of free thyroid hormone (mainly T4 and T3) are too low. This triggers the feedback loop to the brain to produce TRH and TSH. When levels of TSH rise, the thyroid puts out more and more thyroid hormone. This explains why a HIGH TSH is a diagnostic criterion for hypothyroidism.
Technically speaking, TSH is a brain hormone and not a thyroid hormone!
Symptoms of Low Thyroid include:
- Fatigue
- Sluggishness
- Difficulty concentrating
- Feeling cold all the time
- Coarse, dry hair
- Thinning hair
- menstrual irregularities (lack of period, irregular periods, or abnormally heavy periods)
- Subfertility
- Decreased libido
- Fluid Retention
- Constipation
- Weight Gain
- Fibrocystic breasts
- Polycystic Ovary Syndrome
- Premenstrual Syndrome (PMS)
- Feeling of rapid heart-beat or skipped beats
- Elevated homocysteine
- Galactorrhea (being able to express milk without being pregnancy or actually lactating)
The root cause(s) of hypothyroidism can first be split into two major groups:
1. Autoimmune
– Hashimoto’s
2. Not autoimmune
– Inadequate production of thyroid hormone (not enough thyroid hormone coming out)
– Cellular resistance to thyroid hormone (thyroid hormone being produced, but either not converting to “active” form and or not being used by cells the right way)
It is important to determine the root cause of your hypothyroidism so that you can best manage it. While the medication intervention may be consistent regardless of the etiology, the nutritional and lifestyle management do differ depending on the root cause. For example, let’s say your root cause of hypothyroidism is autoimmunity. If there isn’t a plan in place to manage your autoimmune disease, then the destruction of your thyroid will continue. Medications help to replace the lost thyroid hormone, but don’t stop the disease progression.
Additionally, let’s say that you have cellular resistance to thyroid hormone. Taking more medication may not help as much as you would hope for if the hormone isn’t getting INTO your cells. The goal of nutritional therapy is to get your body to a place where it is more responsive to your medications and allows for the most optimal functioning of your thyroid (which varies from person to person depending on their disease progression!).
With all this information, you can see why assessing just “TSH” is not enough!
Ask for a Full Thyroid Panel to Get the Full Picture!
A Comprehensive Thyroid Panel (Should) Include:
- Free T3 (Free Triiodothyronine) – the more potent and biologically active thyroid hormone, T3 regulates growth and metabolism throughout the whole body.
- Free T4 (Free Thyroxine) – considered a precursor hormone, T4 is converted to T3 as required by cells throughout the body; levels of T4 are generally much higher than T3.
- Total T4 (Total Thyroxine) – Most T4 in the blood is bound to carrier proteins which make it biologically inactive. Total T4 includes unbound (free) T4 plus T4 that is bound to carrier proteins in the blood.
- rT3 – Reverse T3 (Reverse Triiodothyronine) – As the name implies, Reverse T3 opposes the biological action of T3. It slows metabolism and renders T3 in the body biologically inactive. The rate of rT3 production relative to T3 will increase in times of stress (high cortisol) and in the presence of nutrient deficiencies, inflammation or certain medications.
- Thyroid Stimulating Hormone (TSH) – produced by the pituitary gland, TSH tells the thyroid gland to increase or decrease production of T4 or conversion to T3 depending on the amounts circulating in the bloodstream via an efficient feedback system.
- Anti-TG (Antibodies to Thyroglobulin) – a precursor to T4. If Anti-TG are present in significant amounts, this suggests an abnormal immune response against your own body, also called autoimmunity.
- Anti-TPO (Antibodies to Thyroperoxidase) – is an enzyme that initiates the synthesis of T4. Antibodies to TPO indicate autoimmunity where the body is attacking normal proteins in the blood (in this case, TPO). People with anti-TPO have a higher chance of developing hypothyroidism that those who do not have antibodies to TPO.
- Tg (Thyroglobulin) – The main function of Tg is to store iodine, which is a necessary nutrient for the production of thyroid hormones T3 and T4. This test is particularly useful when monitored over time versus a single measurement and can sometimes be a useful tumor marker in patients with previous thyroid cancer.
- TBG (Thyroid Binding Globulin) – is a carrier protein for thyroid hormones so its role is to transport T4 and T3 through the bloodstream. The thyroid gland adjusts to changing levels of TBG in order to keep free T4 constant and it is particularly useful when thyroid (T4) levels do not necessarily correlate with clinical symptoms. TBG levels are largely affected by other hormones and many prescription drugs and is useful in diagnosing the reason behind abnormal thyroid hormone levels.