Having a Functional Endocrinology based practice I often focus on disorders pertaining to sexual function so I want to describe to you a rather obscure tidbit pertaining to estrogen and its relationship to thyroid function. Low thyroid function is something that I talk a lot about because it affects a great many people whether they know it or not. Indeed the thyroid gland is very misunderstood and is certainly mistreated through the mainstream approach. But the thyroid gland itself aside, this article is focused on how thyroid hormone activity (not thyroid hormone production) can be hindered due to imbalances in the sex hormone estrogen.
When looking at thyroid hormones, or any hormones really, it is important to differentiate between the protein bound and free forms of the hormone. When a hormone is created by a gland it is immediately bound up with a carrier protein who’s job it is to get that hormone to where it needs to go without being destroyed or lost along the way. Once the hormone is where it needs to be that carrier protein is removed and the hormone is “free” to do its job. That is why these hormones are called “free fraction” or “free hormones.”
In the case of thyroid hormones there is a specific carrier protein called Thyroid Binding Globulin. It just so happens that when there are elevated levels of estrogen the amount of Thyroid Binding Globulin in the blood also goes up. This increased number of binding proteins hold onto more of the thyroid hormone which works to hinder them from doing their job. Remember, protein bound hormones can’t bind to their receptor. They just float around in the blood. So if you were to do a basic thyroid screen you would usually be looking for the protein bound form (generally due to the lower cost of the test) and everything might look fine. The thyroid is producing plenty of hormone and the paperwork all looks great. But why then is this woman still having trouble losing weight, losing her hair, struggling with low energy, and not pooping very often? These are all low thyroid symptoms which exist even though the actual hormone levels are normal. “Go home, there is nothing wrong with you.” Right? Hmmm….
The reason that these symptoms persist is because the elevated estrogen induces a low thyroid state by stopping the free form of the hormone from binding to the receptor. For all intensive purposes this person is low thyroid. The unfortunate part is that the average blood work up won’t account for the interplay between estrogen and thyroid Binding Globulin.
A careful history looking for high estrogen conditions like breast cancer, breast cysts, endometriosis, uterine fibroids, or hormone replacement therapy for example should all come into play when considering complaints of low thyroid function. This is thinking outside the box of mainstream medicine. These cases are missed all the time which is unfortunate. It is also of course a great idea to have a look at estrogen levels and there is even a test for Thyroid Binding Globulin. These are tests that I can order if your primary physician is unable or unwilling to order them for you. Be prepared for such a response.
This is just another example of how hormone imbalance can have a negative affect on sexual function and health in general. Let’s face it… Someone who is experiencing low thyroid symptoms for any reason is generally low energy. And I think that we all know how great sex can be when one or more of the people involved is, “too tired!” Let’s be proactive here. Healthy sexual function can translate into great overall health and lend itself to a positive outlook on life. It is as natural as breathing, sleeping, and pooping! And when it comes to thyroid health all of the above can be involved. The solution may be as simple as just looking for the right thing.