How does the thyroid function (or not)?

Today I’ll be continuing my series on hypothryoidism and the thyroid.

What is a thyroid anyway and what does it do?

The thyroid is a small gland located in the neck. It’s role is to absorb iodine from the diet and  combine it with the amino acid tyrosine to create the thyroid hormones T3 and T4. How the thyroid “knows” to produce thyroid hormone involves a complex chain of signaling hormones.

  • First the hypothalamus in the brain sends a hormone signal called Thyrotropin-releasing hormone (TRH) to the pituitary in the brain.
  • The pituitary then sends a hormone called thyroid stimulating hormone (TSH) to the thryoid itself which tells it to create thyroid hormone.
  • 96% of the thyroid that the the thyroid gland produces is in the “inactive” form of T4 and approximately 4% is in the “active” or working form of T3 which occurs in the thryoid as well as in other organs live the liver and the intestines.
  • Most of the T3 (and T4) in the body is attached or bound to a protein found in the blood. The most active form of T3 is called free T3.

If your thyroid is functioning properly it converts T4 to T3 as needed to perform essential bodily functions and you have enough free T3 floating around to do the necessary work in the body. However, if the thryoid is not functioning properly either due to a deficit in iodine or, most commonly, Hashimoto’s Thyroiditis (autoimmune thryroid disease) or due to some other form of thyroid disease, you might not make enough T4 or the T4 does not get converted properly to T3 or the T3 stays bound up.

The active thyroid hormone T3 gets to every tissue in in the body to keep multiple organs in the body working as they should. So, when we don’t have enough functioning T3 many body functions will be affected.

So do you see now why I like my clients to be testing robustly for thyroid disease? It’s entirely possible to have a completely NORMAL or mildly abnormal TSH (the only thyroid marker many medical providers test for) and even a normal T4 but to have low T3 or low free T3 and feel the effects of thyroid disease.

To fully research whether or not you have thyroid disease I suggest you also get tested for: TSH, Free T3, Free T4, Total T4, TPO (thyroid peroxidase) and anti-thyroglobulin antibodies. It’s important to work with a thoughtful medical provider who can test you you properly to not only uncover thyroid dysfunction but also work on some of the root causes.

Next week I’ll talk about some basic steps for treating thyroid disease.

Please note that this article is for information purposes only. Always check with your medical provider before starting any treatment.