Log in
Thyroid UK
93,777 members107,773 posts

Iodine: Friend or Foe for Hypo?


I know that iodine deficiency can cause hypothyroidism.

Then how come that some articles suggest the hypo patients cut iodine from their diet?

11 Replies

Inadequate iodine causes hypothyroidism.

Worldwide, this is probably the leading cause of hypothyroidism. Appropriate dietary adjustments and various forms of supplementation can be beneficial and restore adequate thyroid hormone levels (though cannot repair all the damage done).

In the USA and the UK (and many other countries) autoimmune thyroid disease (Hashimoto's) is the leading cause. The interaction of AITD with iodine is not obvious and simple.

High levels of iodine (such as occur in some supplement regimes) can actually cause hypothyroidism.

Iodine and hypothyroidism is a complex subject with many different views - many clashing.

My take:

Before even considering any iodine supplementation, do a lot of reading. Absolutely don't go with the first theory or article you see.

Do not make major changes to iodine in your diet unless there is something very obvious like regularly eating high iodine foods or realising you have an extremely low iodine diet. Even then, make changes thoughtfully and (usually) slowly.

I absolutely DO NOT fully understand iodine and thyroid. So be wary of anyone who claims they do understand them.


FleureDee I don't think it's a case of cutting iodine from diet, more a case of not supplementing with iodine unless there is a known deficiency so testing is advised before supplementing.

For patients with Hashimoto's, too much iodine can increase the autoimmune attacks.

Also, for people taking Levo, it contains some iodine - I can't explain that very well but I'm sure someone else will, greygoose knows all about that if she's around.


If one is hypo. but not auto- immune (hashis) how does one stand re. iodine?.


I suggest the first thing is to assess your dietary intake (so far as possible) then get tested.


Thanks, makes sense!

1 like

You test to see if you are deficient:

Genova testing through ThyroidUK thyroiduk.org.uk/tuk/testin...

"Urine Iodine Test:

Specimen requirements: Urine

Cost: £71.00

Order Code: END25

Turnaround time: 16 - 19 days

Iodine is an essential trace element, vital for healthy thyroid function. Adequate levels are required to enable the production of T3 and T4 thyroid hormones, whilst also being required in other areas of health.

Deficiencies can lead to impaired heat and energy production, mental function and slow metabolism. Urine iodine is one of the best measures of iodine status. This test is not performed as a loading test, but can be used to establish existing levels or to monitor iodine supplementation."

Why the iodine loading test is not recommended: blog.zrtlab.com/flaws-in-th...

If you're found to be deficient you can increase iodine from food. The British Dietetic Association has a food fact sheet on iodine levels:

bda.uk.com/foodfacts/home > scroll down to Nutrients In Food > Iodine (I can't link to PDFs on my tablet).

If necessary you can supplement but that's usually only recommended under the guidance of an experienced practioner as I believe it has to be balanced with Selenium.

1 like

Thanks for reply and links, will investigate. - don't think I was intending supplementing anyway, I always (if poss.) try to get nutrients from food


I've never heard of anyone suggesting you cut iodine from your diet, except for people who are having RAI treatment - but that's another story.

Iodine is one of those things you need just the right amount of - not too much and not too little. Iodine in excess can cause thyroid problems, just as a deficiency can. Iodine is one of the ingredients of thyroid hormone - which is why a deficiency can cause hypothyroidism, the gland cannot make enough hormone if it doesn't have enough ingredients.

One molecule of T4 contains 4 atoms of iodine. Which is why it's called T4. One atom is removed to make T3. The released atom of iodine goes back to the thyroid to make more hormone. Which is what SeasideSusie means when she says that levo contains iodine.

So, with the iodine you get in your food, plus the recycled iodine from the levo, a hypothyroid patient gets quite a lot of iodine. You really don't need to add anymore - especially as you need less because your gland isn't making as much/any hormone.

For someone who isn't hypo, excess iodine can cause them to become hypo - or hyper (not quite sure how that works) - or, it can trigger Hashi's. And, for someone with Hashi's, it can make your symptoms 100% worse! I speak from personal experience, there!

So, iodine is neither friend nor foe. It's just another nutrient, a mineral. And like other minerals - iron, calcium, etc - you need just the right amount - not too much and not too little.


I agree with the other posters but have read that IF supplementing iodine it is advised to supplement selenium as well.

1 like

Hello everyone,

Here is a study published in pubmed that says the cutting iodine intake was beneficial for hypo patients:


This site also mentions something about cutting iodine intake:


Anf this:



"It’s commonly believed that hypothyroidism is due to insufficient iodine, but this isn’t true. Dr. Kharrazian states that if you have Hashimoto’s, taking supplemental iodine is like throwing gasoline on a fire, so eschew iodine supplements and iodized salt. Primary sources of iodine: sea vegetables and seafood. Secondary sources: eggs, asparagus, lima beans, mushrooms, spinach, sesame seeds, summer squash, Swiss chard, and garlic."

What I did is that I discarded my table salt which is fortified with iodine, and started using pink Himalaya salt.

I hope I did the right thing, not so sure though.

Thanks :)


As helvella has said, you should not immediately believe anything you may read about thyroid issues. Get a balanced view about all matters as those produced from "official" sources are notoriously dodgy to say the least. You would do far better believing what you read on forums such as this where actual patients can relate their personal experiences. Iodine is not a subject I understand at all well. What I do know, however, is to avoid taking too much.

1 like

You may also like...