Iodine Iodine iodine…. all day i see Iodine
Iodine deficiency is the most common issue I pick up when screening patient thyroid results. I generally assess this by looking at T4 levels, and to a lesser degree the ratio between T4 and T3.
T4 is made of tyrosine, which is an amino acid found in protein, and also 4 molecules of iodine. So low T4…. low iodine. Pretty straight forward, right?!
I’m sometimes a bit of a nerd when it comes to numbers and test results, so I’ve tracked the results of 70 patients who have had low T4, and who I have followed up with a 24hr iodine loading test. The results are quite black and white. 92% of patients with low T4 were iodine deficient! As an aside, the TSH value was often within the functional range of 1-2mIU/L, which just goes to show that relying on TSH alone is NOT an effective way to assess thyroid function.
Symptoms of Low Iodine
Low iodine will cause hair loss, dry skin, brittle nails, poor temperature control, poor libido, fatigue, brain fog, slow metabolism, easy weight gain, and trouble losing weight. Correcting iodine often brings a considerable improvement in these symptoms, and most people can finally stop taking thyroid medications.
How do we correct this?
So what happens when we give patients iodine? Firstly, we need to make sure all of the cofactors are onboard so that T4 can convert to T3 properly. This may involve Selenium, Zinc, Iron, and reducing stress. T3 does 95% of the heavy lifting for the thyroid, so there’s no point bumping up T4 if it can’t convert properly. In fact, things can go sideways if conversion nutrients haven’t been addressed before starting iodine.
Alright, lets say the conversion factors have received a tick of approval, iodine has been started at the appropriate dose for the individual (we’re all unique snowflakes remember), liver support is onboard, and all is going smoothly….
The doctor flips out, he curses me and my fish slapping ways, and puts you straight back on high doses of thyroid medication to get the TSH down.
Wait…. but you still feel most excellent. The only one not feeling great is the doctor! What’s the deal?
Why TSH goes up with Iodine supplementation
This is a common occurrence when someone starts to take iodine after being deficient. The body increases TSH, which is needed to make iodine symporters. Iodine symporters are what drive iodine into the thyroid cells (see pic below). They’re like entry gates at a busy sporting event which let people through. The more people that have tickets, the more gates need to be opened to let them all through. TSH increases to make more entry gates. If enough gates open, the extra iodine can get into the thyroid cell, which then creates more T4, and finally T3.
Individuals can have elevated TSH levels for up to 9 months without clinical signs of hypothyroidism. If there is a concern, the best values to check with labs are Free T3 and Free T4. You will find in most cases that the “frees” are nicely within the ranges.
This is one case where the truth does not reside in the pathology result. It can’t be taken on face value. Symptoms provide a WAY more accurate picture.
Please print this blog out, or bookmark the page to keep it on hand if you’re planning to retest your thyroid after using iodine. You may need to give it to the doctor, before they have a coronary of their own.