The Linus Pauling Institute link which mrsD has provided is worth a careful read.

The Linus Pauling Institute is a reliable source of information - it is independent of any commercial entities.

From that link, the Tolerable Upper Intake Level (UL) for iodide is about 1 mg/day.

Consuming iodide in excess of this UL can lead of hypothyroidism, for reasons which are explained in the link.

In my opinion, this is something which people who choose to self-medicate with iodide at levels which are significantly above the UL should give careful attention to.

Hey Kiwi, 1mg is 1000mcg right? The US RDA says 150mcg....pretty low don't you think.

Getting iodine can help make our thyroids healthier....there is massive info on this too. There are 100's of links on the iodine issue from a mass of people who has researched and worked this issue for years. One major reason for HypoT is inadequate iodine getting to the thyroid.

Caroline, yes 1 mg is 1000 micrograms. However, that is the UL - people whose daily iodide intake is significantly greater than that are at risk of hypothroidism.

The RDA for iodide is indeed 150 micrograms/day. I don't know whether or not that is too low. If somebody chooses to increase their daily iodide intake to (say) 500 micrograms/day that probably will do no harm and might help, as long as they stay below the UL of about 1 mg/day.

More generally, thyroid hormone production is controlled by a complicated feedback loop involving the thyroid gland, the pituitary gland and the hypothalamus.

Thyroid hormone production is usually self-regulating though hypothyroidism or hyperthyroidism can arise from pathology involving any or all of those three tissues. Hypothyroidism is usually not a direct consequence of iodide deficiency, as along as the daily intake is comfortablely above the RDA but below the UL.

hi kiwi - just checking - do you mean increasing iodide intake can cause hypothyroidism (under-active thyroid) or hyperthyroidism (over-active thyroid)? I always get the two mixed up so please correct me if I've done so again. Thanks for the interesting links as always.

Oops, my mistake/typo bluesfan.

Excess iodide (above the UL) can lead to hypothroidism, not hyperthroidism because it triggers increased production of TSH, which inhibits thyroid hormone production, leading to hypothyroidism.

This is in the "Excessive iodine intakes" section of the link that mrsD provided.

Thanks again kiwi - you've clarified it for me and reminded me that I have to think about my test results sort of in reverse - ie: the higher the TSH no. the better as you explain. Short-term memory lapses are the pits when it comes to trying to remember this type of back-to-front result.

I've bookmarked that site for the next time I forget.

Just a reminder.. In the Linus Pauling monograph
the excess use of iodide in patients with SUFFICENT
Iodide levels the hypothyroid consquences have been
Seen. I would surmise that people who self medicate
with ultra high doses they read about on some internet
sites would be more likely to suffer these effects.

Therefore medical testing to confirm low iodine should
be done and any high doses above the Upper Limit
should be supervised by a doctor.

Hi all, as for testing by doctor, I had to lend my book on Iodine Deficiency by Dr. Brownstein to my integrative MD....she was not up on this issue. I never tested at her office...I learned of this possible issue from Dr. David Williams in his Alternatives newsletter and it made so much sense. I don't eat MUCH seafoods, I eat some, and don't use table salts. Cooking some salmon today, but I don't eat fish many days. So for me, it made sense.. Here is home test I've done many times over the years and iodine disappears pretty quickly. This is done with iodine tincture.

http://www.drdavidwilliams.com/iodine-deficiency-test/

Personally, I think conventional MD's would give a blank look if you asked for a test...