January 12, 2015

Dr. David Clark, DC – Raleigh-Durham-Chapel Hill thyroid expert, explains how Vitamin A Deficiency causes Low Thyroid symptoms.

Hidden Cause #22 why you STILL have low thyroid symptoms, even though you may be taking thyroid medication…and even though your lab tests look normal is:

Vitamin A deficiency causing thyroid hormone receptor malfunction 

Let’s talk about what normally happens…

  1. Inside every cell is a RECEPTOR for T3. 
  2. T3 enters the cell and DOCKS on the receptor (like a key in a lock). 
  3. The cell RESPONDS and a message is sent to the nucleus (where DNA and RNA live)
  4. DNA and RNA start to do their thing and code for proteins that make you NOT have low thyroid symptoms

Vitamin A deficiency SLOWS DOWN THE RESPONSE inside the cell. This creates a sluggish response to T3, and low thyroid symptoms like these:

  • hair loss
  • weight gain
  • constipation
  • brain fog
  • fatigue
  • needing to sleep an excessive amount of hours just to function
  • infertility
  • miscarriage. 
  • high cholesterol

This particular kind of problem has nothing to do with your blood levels of T4 and T3, Free T4, Free T3, Reverse T3, or Thyroxine Binding Globulins.  So, blood tests of your “thyroid function” will not show this problem.

Who would have vitamin A deficiency? 

Vitamin A deficiencies should be expected in someone who is iron deficient…or drinks a lot of alcohol…or has liver problems.

Iron deficiency (or Iron need) can be picked up on blood tests by looking at:

  • Ferritin (the most sensitive indicator of your body’s iron status)
  • Serum Iron, Iron Binding Capacity and Percent Saturation
  • CBC with Differential 

NOTE: the lab ranges are REALLY wide and forgiving. I use a “functional” or optimal range.

Liver dysfunction can be detected by testing  “transaminases” or “liver enzymes”:

  • AST
  • ALT
  • GGT

If these markers are above the lab range, there’s probably some kind of liver inflammation going on, and the cause has to be tracked down.

Again, in this scenario of Vitamin A Deficiency affecting Receptors and Response, the thyroid blood tests will look normal.

A woman will usually go to see her doctor because of those low thyroid symptoms I listed above.

And if the doctor runs a T4 and TSH, they’re not going to see anything wrong.  They may even run a “full thyroid” panel (which usually just means testing a Free T4 or Free T3).

Maybe this doctor is really sharp and they run all of the thyroid tests you can order….and the results come back as normal—but you still have low thyroid symptoms. 

Now, the big mistake– is to give you thyroid hormone medication like Synthroid® or Levothyroixine anyway—Even though your quantities of hormones are clearly normal.

I believe if the doctor is going to give you something (medicine, supplement, whatever) they need to have a reason for why they’re giving it to you. 

I mean, the doctor that looks at those normal numbers and says, “Take iodine.”  Mistake. 

The doctor who looks at those normal numbers and says “Take tyrosine.” Mistake.

There’s nothing there.  The doctor needs to consider that there IS another reason for your symtpoms.

What is a symptom vitamin A deficiency? 

The absolute classic sign of vitamin A deficiency is problems with night vision.  Even though you don’t have an astigmatism.  Night vision difficulty with no astigmatism is classic vitamin A deficiency. 

Vitamin A deficiency has to be suspected in someone who has that symptom…

….especially if that person ALSO has iron deficiency, elevated “liver enzymes” or is drinking a lot alcohol.

This particular hidden cause is fraught with a lot of challenges for the clinician and a lot of challenges for the patient.  You have low thyroid symptoms but your thyroid numbers literally do look normal. 

NOTE #2:  please don’t start taking vitamin A without some guidance.  If you take a lot of vitamin A, it can suppress the activity of Vitamin D.  And you can get yourself in a lot of trouble.

My recommendation:

You need to find a doctor who understands that there’s a lot of moving pieces on the chess board here–not just looking at your bloodwork and saying:

“Everything looks fine. You must be fine.” 

This isn’t good enough….because there ARE some causes for low thyroid symptoms in which all the labs look fine.  Vitamin A deficiency could be one of them in your case. 

© 2014 David Clark. All Rights Reserved.

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.

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