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Are thyroid hormones important to deliver iodine to target cells (by deiodination)?

I believe the LXR, whose activation could be elevated on a low carb diet, could be involved in NIS (iodine transporter) upregulation. LXR could also be a kind of antagonist to thyroid hormones metabolism.

https://pubmed.ncbi.nlm.nih.gov/31170473/

https://pubmed.ncbi.nlm.nih.gov/20176747/

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Very useful, thank you. Here is another study: https://sci-hub.se/10.1016/j.mehy.2004.02.033

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"If you are carb-dependent, and there are people who are unable—through atrophy of the fat-burning system—to burn fats,"

Are there such persons? What does being "carb-dependent mean?

Even if we consume no fats and all carbs, a lot of these carbs are going to be converted to fat and then burned as fat.

Only thing that can be said to be carb-dependence is Crabtree effect when a cell uses glycolysis even in face of abundant oxygen. But the crabtree occurs in advanced diabetics only I suppose.

You say that going low-carb lowers body temperature and is good (or at least not bad). But there are other people going about saying that there is actually an epidemic of low body temperatures and which is caused by PUFA!

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Ever since learning about PUFA (I was keto before) I have suspected that many keto studies might be confounded by the researchers using "heart-healthy" oils to help their test subjects hit fat macros... because those evil, dangerous saturated fats would earn the ire of ethics boards. Haven't done the hard work to actually verify this, though.

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If you want complicated, try going low-carb/animal-based/carnivorish with NO THYROID! It’s no fun! The standard of care is levothyroxine AKA SYNTHROID AKA T4 only treatment. It’s easy for MDs to give this single Rx which is dosed mostly by patient weight, symptoms to a point, and basic thyroid testing, not the full panel and not taking into account continued symptomology. An MD will tinker a bit, then stop. The patient usually needs to be educated and ask for T3(liothyronine/Cytomel).

Why do you need T3 when T4 converts to T3? Because your former thyroid also made T3 (and T1 and T2). Due to many factors, the liver may have trouble converting enough T4 to T3. An inverse problem then occurs — your body says “whoa — too much T4! Something must be wrong, shut down, shunt T3 to Reverse T3!” Your body does this in a trauma situation to lower metabolism, slow down and heal. Patients in the ER would have elevated RT3. But many thyroid patients slowly build up RT3 which drops you into hypothyroid symptomology.

Guess what happens when you lose weight on low carb but you are on the same Rx for T4 every day? That’s right, you get increased RT3 build-up. Then you hit the wall and all your hard work slowly reverses and you don’t have enough energy to make it through the day.

In my case, when I was about 6 weeks in, my endocrinologist reduced my meager T3 dose from 5mcg 2x/day to 1x/day. I turned I to a zombie. I had extra T3 from an auto Rx that was never stopped so started taking it 2x/day again. But still felt crappy. Then had to ask to have the SYNTHROID/T4 reduced to be more in-line with. 20lb weight loss. But it was too late, the RT3 was in process and will not stop when you give T4. You really need to do only T3 to get back on track and it’s near impossible to find and MD who will do this. I’ve been on a waitlist for more than a year for a functional DO who I think will work with me. And all my “skinny” clothes are getting tight and I continue to be narcoleptic by 7pm.🎉

Maybe someday, some bio-engineer will come up with a device like a CGM so thyroïdectomie patients can dose as needed.

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