Hello everybody, it's Dr. Eric Balcavage and we're back for
another edition of Thyroid Thursday.
Today I want to talk about the number one reason why you
have chronic hypothyroid symptoms. This is something that your doctors are
missing the boat on if you have chronic hypothyroid symptoms. It all comes down
to thyroid hormone availability versus utilization by your cells.
Let me give you a little run through of thyroid physiology
again. TSH stimulates the thyroid gland to produce T4 and T3. T4 being the
primary inactive hormone that's made by the thyroid gland. T3 is the active
hormone but very small concentrations are made by the thyroid gland. Most of
the cells in your body prefer T4 versus T3 because they like to control the
activation of thyroid hormone within the peripheral cells.
T4 and T3 is made by the thyroid gland and it enters the
bloodstream. T4 and T3 is bound to carrier molecules. The most common is
something called "thyroid binding globulin." The blood flushes over
your tissues and cells and when the blood meets tissues and cells that need
thyroid hormone, T4 and T3 leave that thyroid binding globulin and become free
T4 and free T3. Free T4 and free T3 is then able to actively be transported
into the cells and that's important. It's an active process, it means it
requires energy.
Once inside the cells, T4 can be converted to T3 and that T3
can reach your nucleus. Any T3 that's coming into the cell directly can go to
the nucleus and be used to bind to the nucleus inside your cells. Once T3 binds
to the nucleus of your cells, then you can increase cell metabolism. If you
have hypothyroid symptoms, this is not happening sufficiently.
Most doctors assume that if you have plenty of thyroid
hormone available because your blood values of T4, T3, free T4, and
free T3, that the only mechanism that's going happen is that T4 and T3 is going
enter the cells and it's going to bind to the nucleus. But if you have chronic hypothyroid symptoms,
that is not happening.
So, what's the difference between availability and
utilization? Well, let me talk about that.
Thyroid hormone really has three things that occur to it
once it's produced. The first fate of thyroid hormone is this activation step.
T4, and T3 enter the cells. T4 gets converted to T3, what we call activation,
and T3 binds to the nucleus. Doctors assume that if you have plenty available
(T4 and T3) that this is going to happen. Unfortunately, there's two other
fates that can occur to thyroid hormone.
The second fate is deactivation. That means that T4 can be
deactivated to reverse T3 and to T2. T3 can be directly deactivated to T2, and
T4 can be deactivated to reverse T3, which can then be further broken down to
T2. Both forms, reverse T3 and T2, are less active forms of thyroid hormone.
They do not bind to the nucleus and therefore they do not stimulate metabolism.
That's one of the problems.
The other fate of thyroid hormone is excretion Not all
thyroid hormone makes it to the cell. It can be excreted through the liver, go
out in your poop or out in your urine. Once these thyroid hormones enter the
cell, they can also be transported back out and go out to the body or be
excreted.
Only one of the fates, the activation fate, is going to
result in increased metabolism, increased T3 binding to the nucleus, causing
you to have healthy metabolism and not have hypothyroid symptoms.
So, the next question might be, "What causes all this
deactivation?" Well, we've talked about this multiple times on Thyroid
Thursdays, and that is that cell stress determines what happens with thyroid
hormone. If you have excessive amounts of stress inside your cells or tissues,
you're going to potentially have more deactivation and excretion occurring.
Now, what causes cell stress? Any drop in energy within the
cell, and that can be caused by multiple reasons. Toxins and microbes are big
causes. Bacteria, viruses, all types of microbes can cause more cell stress and
more deactivation of your thyroid hormone.
When your doctor says you have plenty of T4 and T3, free T4
and free T3, they're saying you have plenty of thyroid hormone available, which
may be true, but it doesn't necessarily mean it's being utilized to stimulate
metabolism. You could have decreased transport into the cells. You can have
decreased activation of thyroid hormone. You may not have sufficient levels of
T3 occurring. Any of these steps being blocked is going to result in decreased
thyroid hormone, T3 specifically, getting to the nucleus of the cells. This is
going to result in hypothyroid symptoms.
So, what do you do?
You're going to have a hard time convincing most of your
doctors about this model. It doesn't matter if it's your conventional medical
doctor, family practitioner, or the endocrinologist. Most just look at hormone
availability not the utilization factor.
You need to work many times with a functional medicine
practitioner to determine what's causing this deactivation to occur and this
increased excretion. It's not looked at in conventional medicine. If you find a
functional medicine practitioner, one of the things we're going to focus on is
what's causing your cell stress. If we remove cell stress, then the activation
process is going to occur more efficiently. You're going to get more T3
reaching your cells. And, you're going to have increased metabolism.
You can work on some of this on your own but understand that
any stress; physical, chemical, emotional, or microbial, beyond your cells'
ability to adapt is going to cause deactivation of thyroid hormone and
increased excretion of thyroid hormone regardless of how much is available.
Hopefully that answers some of your questions about how you
can still have hypothyroid symptoms when TSH, T4, and T3 are normal, and when
your gland is functioning fine. This step, this deactivation and excretion
occurs away from the thyroid gland, so all this deactivation of thyroid hormone
occurs away from the thyroid gland.
Hopefully that helps. Look forward to another Thyroid
Thursday in the coming weeks. If you have any questions regarding this or any
Thyroid Thursday, you can reach out to me wherever you watch the videos. Just
put your comment below and I'll be sure to answer it. Take care.
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