Hidden Cause #13 why you still have low thyroid symptoms even though you may be taking thyroid medication, and even though your lab tests look “normal” is ..
Underconversion of T4 into T3 caused by a deficiency of co-factors and high levels of cytokines.
What is “conversion?”
About 97% of what the thyroid gland makes is T4, which is bascally inactive. T4 must be converted into T3, which IS active.
How does conversion happen?
An enzyme called 5′-deiodinase performs the “conversion.” Conversion takes place primarily in the liver. Certain important co-factors must be present in order for this enzyme to work correctly. The #1 co-factor for this conversion is selenium. (You may have heard of selenium).
What are the symptoms of underconversion (low conversion)?
Typical symptoms are your “classic” low thyroid symptoms:
- depression
- hair loss
- weight gain
- brain fog
- dry skin
- dry hair
- high cholesterol (may not be from your diet. T3 is is the “co-factor” to convert cholesterol into your hormones).
- constipation
- infertility
What does underconversion/low conversion look like on blood tests?
On lab tests (assuming the doctor is actually ordering these)…you may notice that the Reverse T3 is low. That’s one little indicator of how much conversion is happening.
But you might also see:
- Free T4 low
- Free T3 low
- Or you may see total T3 levels low
Or you may not see any abnormal lab results. You may have only the low thyroid symptoms.
What could cause a deficiency in selenium ( or a “need” for selenium)?
The #1 suspect is malabsorption.
Then you have to ask “Why would someone not be able to absorb selenium?”
First thing you have to consider is insuffficient stomach acid, called hypochlorhydria. Now, not too much stomach acid, but not enough stomach acid.
If you don’t have enough stomach acid, you can’t demineralize your food. You can’t suck the minerals out of it, and over time you’ll have depleted selenium levels. Selenium wont’ be present in sufficient quanitiy to be a co-factor for 5′-deiodinase to convert T4 into T3.
What would cause low stomach acid?
The first thing you look at is a Helicobacter Pylori bacterial infection. The best test to check for this, in my opinion, is a Urea Breath Test. Hopefully, the doctor you’re working with will know about this issue and also know how to help you eradicate it, if you’ve got it.
Increased levels of cytokines is the second factor that causes low conversion of T4 into T3, and low thyroid symptoms.
Cytokines are immune system messengers. They are part of inflammatory process.
So, if you have gastrointestinal inflammation or arthritic inflammation in a joint…
…or if you have any autoimmune disease like Hashimoto’s, rheumatoid arthritis or multiple sclerosis…you will have a high level of circulating cytokines.
Cytokines block conversion of T4 into T3 by slowing down enzyme 5′-deiodinase enzyme.
This next part is critical for you to understand:
You can have two problems at the same time.
For example, a person can have Hashimoto’s that’s destroying their thyroid gland from the inside out…AND…simultaneously have high levels of cytokines that are blocking the conversion of T4 to T3.
You can have two problems at once. There’s no rule that says you can only have Hashimoto’s. You can also have side effects of Hashimoto’s.
Or the inflammation from another problem such as rheumatoid arthritis, or gluten sensitivity or a leaky gut can be causing the cytokines to be high and slowing down conversion. A good doctor has to do a inflammation scavenger hunt to track down the possible source of inflammation.
Here’s the take-away:
If you have any of the following, your doctor should be suspecting a conversion problem:
- low thyroid symptoms
- low reverse T3 on blood test
- low T3 or low free T3
- You were prescribed Cytomel® because you didn’t get better on Synthroid® or levothyroxine. Synthroid® and levo are T4 and must be converted into T3. Taking Cytomel® bypasses the need for conversion…but…does NOT address the underlying problem that cause the converstion problem in the first place.
Underconversion/low conversion can be caused by a selenium deficiency, which makes us look at H. pylori and gut malabsorption….or underconversion can be caused by cytokines blocking the activity of 5′-deiodinase.
Who has high cytokines? Persons with inflammatory conditions.
What are inflammatory conditions? Hashimoto’s, rheumatoid arthritis, multiple sclerosis, psoriasis, persons with food sensitivitites.
You’ve got to put on your detective badge and your thinking cap and start looking for these things.
So if you’re still having low thyroid symptoms, this is something that should be considered, so you need to find someone who knows how to look for them and knows what to do if they find them.
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Disclaimer: The contents of this site are for educational purposes only. Nothing here should be construed as medical advice. Nothing here is a substitute for actual medical care. Consult a qualified healthcare professional.