So far, we’ve learned that thyroid is a small endocrine gland located in the base of the neck, it’s very small, about 1 oz, so you cannot see it or feel it, but it’s vital for your health. It regulates the metabolism, growth, development and normal functioning of the whole body because it produces hormones that turn on the mitochondria in the cells. Mitochondria produce energy and heat by burning carbohydrates and fats and sometimes proteins.
Today we’ll talk about thyroid hormones, T4 and T3. Thyroid gland actually makes another hormone called Calcitonin, which regulates calcium metabolism, and I’ll talk about calcitonin in a future lecture, but when we talk about thyroid hormones, we mean T4 and T3.
There are two things you need to make thyroid hormones – amino acid Tyrosine and a mineral Iodine. There are many other things that are important, but these two are absolutely essential.
An amino acid is a building block of protein. There are 20 amino acids from which all the proteins in the world - plant, animal, human - are made. Just like all the hundreds of thousands of words in the English language are made from the same 26 letters. Tyrosine is one of these amino acids. We get amino acids by eating foods that have proteins in them.
Iodine is a mineral that is abundant in the ocean, but not in the soil. There is a lot of iodine in seafood, especially in seaweed. People regularly eating fish and seaweed usually get enough iodine.
You can also get iodine from plants and animals. The problem is, there are areas of the world where iodine in the soil is very low, so plants growing on that soil and animals eating those plants do not get enough iodine. This makes people living in those areas and eating those plants and animals deficient in iodine. In fact, iodine deficiency is the #1 cause of low thyroid in the world.
All of the cells in the body need iodine. Some organs use more, some less, but all use some. The bulk of the iodine we consume ends up in the thyroid gland, about 70-80%. Breast tissue needs iodine, especially during development and during lactation. Salivary glands and lining of the stomach concentrate some iodine, which helps them protect the body from viruses, bacteria and parasites.
In the US, the northern states bordering Canada, especially in the Midwest and Great Lakes, were known as “Goiter Belt” because many people living there developed goiter, which is an enlargement of thyroid gland. To combat that, US government started encouraging the use of iodized salt in 1920s. This was largely successful because we don’t have Goiter Belt anymore, but many people are still deficient in Iodine, which contributes to low thyroid.
Please download the report telling you how to check if you are deficient in iodine. Go to LowThyroidDoctor.com. I will also mention it in one of the upcoming lectures.
Chemical structure of tyrosine is relatively simple. It consists of a round-looking hexagonal center made of carbons. Carbons are attached to oxygen, hydrogen and nitrogen. Plus one or two iodines. Tyrosine with one iodine is called mono-iodo-tyrosine. Mono means one, iodo means iodine, plus tyrosine. If 2 iodines are present, the structure is called bi-iodo-tyrosine, bi meaning two.
The thyroid gland combines 2 such tyrosines with attached iodine. If you put together two tyrosines with 2 iodines each, you get a total of 4 iodines, which is the hormone T4 or thyroxine. Or, you can combine a tyrosine with 1 iodine plus tyrosine with 2 iodines, in which case we get a hormone with 3 iodines or T3.
This all does not happen randomly. There are many special enzymes, special proteins, that make the whole process possible. There are many minerals and vitamins that are required to make it all happen. We will talk a lot more about it in a later lecture.
One important protein from which thyroid hormones are made is called thyroglobulin. Thyroglobulin is made by the thyroid cells. It has many amino acids tyrosines already attached to iodine, so thyroid hormone can be made from it very quickly. Thyroglobulin is stored inside the thyroid gland.
One enzyme that is especially important in thyroglobulin metabolism, iodine metabolism and thyroid hormone production is called thyroid peroxidase or TPO. The reason I mention these names is because they will be important when I talk about blood tests we use to diagnose thyroid problems.
Let’s summarize what we have learned in this lecture. Thyroid cells need many things to make thyroid hormones, especially an amino acid tyrosine and a mineral iodine. Thyroid cells need the help of multiple minerals, vitamins and enzymes. We have also learned that T4 has 2 tyrosines and 4 iodines, while T3 has 2 tyrosines and 3 iodines.
In the next lecture we will learn how thyroid hormone production is regulated and controlled, how thyroid hormones are distributed to provide normal activity. Remember, we are still discussing how things work when everything is normal.
If you know someone who might be interested in low thyroid, please refer them to LowThyroidDoctor.com so they can download this ebook. Also, if you have questions or comments, please email to DrTeplisky@gmail.com.
As an additional bonus, you can get a free, no obligation 30 min phone consultation with me to see if I can help you figure out if you have low thyroid. Just book it online or call my office at 718-769-0997.