Should we take iodine supplements?

Image Credit: miheco / flickr

Should we take iodine supplements?

I’ve had a question regarding iodine for some time. As far as I know there are few options:

– iodised salt
– seaweeds
– supplement

I believe sodium-intake should be minimized, so that’s a no. I’ve also read about many pollutants in seaweeds these days. Is supplementing currently the best way to go?

VinceGreen/Originally Posted in Introducing Joseph Gonzales, R.D.


Iodine intake will depend on your overall diet. Healthy adults need 150 micrograms a day. Iodine is also found in vegetables grown near costal areas but actual amounts of iodine are of course not listed on whole vegetables. I would not rely on coastal veggies as a complete iodine source, however, they do contain some. You are spot on with other sources of iodine coming from iodized salt, seaweed, and supplements.

A majority of folks get their iodine from iodized salt. A 1/4 tsp of iodized salt gives about 45% of the Recommended Dietary Allowance (RDA) for iodine, however, it does have 590mg of sodium, making it not the best choice as the only source of iodine. Sea vegetables such as nori, dulse, and alaria are excellent sources of iodine and do not appear to be polluted. In fact, some research suggests sea vegetables may be beneficial for preventing breast cancer. It is also worthy to note that too MUCH iodine may be as bad as too little. Not a seaweed lover? Don’t enjoy (or cautious) of iodized salt? No problem, a supplement is just fine. You may also be interested to learn about the iodine content in beans! That’s right, Eden brand beans offers a healthy way to get iodine, adding kombu to their cans.

Vegans, especially pregnant vegans, are at risk for iodine deficiency and should consider taking supplements or including iodine rich foods in their diets. Lastly, overconsumption of raw cruciferous vegetables may block the thyroid’s absorption of iodine. As a note of caution: always best to consult with your doctor about supplements right for you.

See Dr. Greger’s optimal nutrition recommendations for more info.

Image credit: miheco / flickr


32 responses to “Should we take iodine supplements?

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  1. I saw a warning label on a package of Emerald Bat nori sheets that said “contains chemicals know to cause cancer and reproductive harm”. It wasn’t on all the packages and I have a picture of it if anyone is interested. The GimMe brand doesn’t tell you which seaweed it is. I guess its eden beans and potato skins for me.

    1. I found the same warning on Dulse … It was a California warning label….I was going to buy some until I saw the label….(having stopped eating salt.) Also eating lots of cruciferous so am at a loss how to get adequate iodine now….maybe see if there are OTC supplements at the drug store?

  2. I’ve seen articles showing cranberries are good sources of iodine (4oz =400mcg)Problem is like the article suggests iodine is not commonly listed anywhere. In fact, the USDA doesn’t even track it apparently or at least not on their website. Any thoughts on cranberries instead of sea veggies for iodine intake?

    1. Didn’t know about cranberries and potato skins for iodine. Will be eating more of them. I added half a bag of cranberries to my muffin batch last night. Also added 1 c of walnuts, which also have some iodine. They were good but I don’t know how much that comes to per muffin.

  3. Hi I had thyroidcancer and I have no thyroid left and I wonder is it dangerous to eat food with high iodine now.Cheese for ex..
    .Or any amount of iodine.Can it activate something in the body ?(cancer..They Think I am cured now.I got an operation and radiojod. I try most of the time to eat vegan food?
    Any suggestions… I eat 150 mg Levaxin..
    Can I take this made of pig instead?There are a subsitute for Levaxin..I read that Levaxin in high doses can larger the heart and give heartattac.I have no thyroid so I must take it for the rest of my Life..
    Thanks for a good website.I try to read it all..

  4. I am currently taking a quarter of an Iodoral tablet daily to combat breast cysts. I have experienced no side effects and I cannot find through research any real negatives for taking this low dose. Are there any negatives I need to be aware of for taking this? Seems to me that if it eliminates breast cysts, that it is a win! Wonder why it’s not recommended more often? Sounds like they use it routinely to treat this problem in European countries.

    1. Hi Ellen. I also have fibrocystic breasts and ovarian cysts. I have asked my GP about Iodine supplementation (I live in Canada). She had no clue about it and after briefly google-ing it she concluded that there isn’t enough data to support it. She sent me for breast ultrasound but the clinic refused to do it because they said that I am nearly 40 and must do mammograms from now on. I am not interested to do mammograms as they irradiate you like crazy and if there is a problem, they will send you to do an ultrasound anyway. So frustrating! Anyway, I read that the usual Iodine protocol to get rid of cysts is 50 mg of Iodine + 100mcg Selenium for 6 weeks, then cut the iodine to 25mg and continue to take it along with Selenium for another 6 weeks and after that cut to 12,5 for another 6 weeks and finally cut further to 6mg for maintenance dose. Let me know if the protocol that you tried worked for you. I am currently taking 1500IU mixed tocopherols vitamin E and it helps manage my breast pain. Also took Evening Primrose which also helps with the pain but I am interested to get rid of these damn cysts once and for all.

  5. I just bought 5 varieties of seaweeds and then I realized they all have different levels of iodine. After much searching I have not been able to find a chart that neatly shows iodine levels and safe dosages for all the different varieties.

    Do you have anything like this?

    1. Contact the company! I recently contacted Maine Coast Sea Vegetables they were beyond helpful. I use their KELP (in the salt shaker, even thought Kelp is SO high in iodine in shouldn’t be in a salt shaker! ha) and I had asked them how much iodine was in 1/4 teaspoon. Their response — “Kelp Blend Granules has approximately 1450 mcg in 1 teaspoon. ¼ of a teaspoon may have as much as 362 mcg!” That means that 1/8 teaspoon (half 1/4) of Kelp has 181 mcg and 150 mcg is the RDA recommended. Should be safe with 1/8. I’ve started taking 1/8 a day, will get my tests done in a month or two and see if my levels have improved! When in doubt contact them don’t try to do the math on their website like I did!

  6. Can you recommend any specific protocols in the whole foods plant based diet for our daughter who has been diagnosed with Hashimoto’s disease other than iodine supplementation? We have not been able to find any recommendations from the WFPBD proponents for the thyroid. She is a collegiate athlete who has put on an excessive amount of weight in spite of her physical activities. Our family is two weeks in to our forever changed dietary lifestyle. Thank you for great informative site!

  7. Hello,

    I am a 35 year old Brazilian woman and I live with Hypothyroidism for 20 years. The only thing I got from doctors was a prescription on Levothyroxine Sodium and eat healthy. But many…. many websites (mostly american) created a list on what we shouldn´t eat once we have this disease such as: kale, broccoli, sweet potato!!! The first two I eat daily and I wonder if eating well has made my health worst.

    I wish there were videos on it.
    I follow this website for more than 2 years and I really trust your opinion.

  8. Hello Anna. I’m a dietitian and volunteer moderator who helps Dr. G answers questions. For people with hypothyroidism (low thyroid) the only concern with eating cruciferous vegetables like broccoli and kale is IF your diet is deficient in iodine. As long as you use a little iodized salt or eat a little seaweed each day you will meet your iodine needs. Dr. G. has a couple of great videos on this topic:
    I hope this puts your mind at ease. Continue to enjoy those healthy greens!

  9. I am curious about thyroid health. Are there any problems with a whole foods/plant based diet with hypothyroid – or hyperthyroid? Any foods to avoid?

  10. HI Bonnie – I’m a dietitian and volunteer moderator who helps answer questions on In the above post, I addressed the myth that avoidance of cruciferous veg when iodine intake is sufficient is unneccessary for people with hypothyroidism. But I was curious to know if there are any other foods to caution since you asked! So, I did a little digging and came across an interesting research summary article by TodaysDietitian ( According to this article there is one food in a WFPBD that people with thyroid disease shouldn’t eat too much of, and that is millet! Millet may suppress thyroid function in people even with adequate iodine stores. Hope this helps!

  11. Hello. I am unsure if anyone is able to answer, but I had a couple of questions regarding Iodine as well. I came across a site that attempts to debunk the help benefits of iodized salt. It states that there are three issues:
    1) Iodine in iodized salts evaporates over time so the amount listed on label at time of manufacture is not correct by the time we purchase and continues to diminish.
    2) Only 10% of the iodine is bioavailable. It also says iodide is added to the salt but so is chloride and chloride cancels the iodide benefits.

    Any insight on this? My husband and I have adopted a plant based lifestyle but it does not include daily seaweed intake. If possible, can someone recommended a safe dosage of Iodine supplement that may compliment what we are eating instead of causing harm? I fear going over or getting to little we do like to use small amounts of salt in food whether it be iodized, sea or mineral.

    Thank you so much in advance!

  12. Hi Jacqueline, Thanks for your question. I am one of the moderators on the website and I wanted to say a pinch of iodide salt on your food is good to provide the iodine that your body requires for Thyroid function. The iodide is added as potassium iodide in iodized salt. Also there are other forms of such as Dulse flakes. I refer you to this video from Dr Greger.
    Avoiding Iodine Deficiency

  13. How much iodine is found in chlorella and spirulina? i take both almost daily (even though Dr. Greger advises against it. I buy them in Germany where they do have stricter supplement controls as in the US, so i hope i will be fine).

    1. here is what i found out after some googling: (may not be accurate since there were no sources cited):
      according to naturodoc website, chlorella has 600mcg of iodine per 100g (presumably in dried form).
      other companies claim their spirulina has about 500mcg / 100g, while others still say theirs has NONE because they don’t add it to their growth medium (water). however it may also have up to 15000mcg…
      The upper limit for iodine is 1,100 milligrams per day, but an overdose is quite rare.
      The US recommended daily intake for iodine is 150mcg so if the first values are to be trusted 20g a day of either cover about 100% or the RDA.

    2. Hi, tazztone. The iodine content of any plant will depend on the soil and/or water in which it is grown. You may want to contact the manufacturer of the supplement you take to find out about its iodine content. Samples of dried spirulina tested by the USDA did not have enough iodine to list among the nutrients in its database. Chlorella is not included in the database at this time. I speculate that spirulina and chlorella grow in fresh water, which does not have the same mineral content as salt water. I hope that helps!

    3. Hey,

      chlorella iodine content (per 100 grams) is 0.4 milligrams

      for spirulina, it’s 0.16 milligrams.

      Hope it helps,

      Moderator Adam P.

  14. I want to use Dulse as my source of iodine BUT…

    Is just half a TEASPOON of dulse enough?

    According to the label on the dulse flakes from Maine Coast Sea Vegetables there is about 330% DV in one TABLESPOON of Dulse so one TEASPOON equals about 150 mcgs. This means that half a teaspoon is only about 75 mcgs right? Is that taking in consideration that I MAY get the rest from other foods?

    If so… I live far from the ocean so the soil here probably has low if any iodine.

    Does that mean that if I use dulse flakes as my iodine source that I should use 1 teaspoon instead of half teaspoon like Dr. Greger recommended?

    Is it ok to eat a teaspoon of dulse every day or is the variance of iodine too big?

    I know that the upper limit is like 1100 mcg of iodine but since I plan on using this stuff every day I want to get as close as possible to the correct amount.

  15. I could be wrong — but it seems KINDA foolish to say this food has this much iodine (or whatever) with absolute certainty.

    Doesn’t it depends what is in the SOIL? This seems so basic, I must miss it.

    Yes, maybe in a test one day 30 years ago, some potatoes showed iodine in the skin. Let’s even pretend they did 50 tests from 50 different potatoes from 50 different locations and the information, at the time, was reliable enough to make an assertion about all potatoes (as an example)

    What about checking that? IS anyone checking that?

    And if you think “Well OF COURSE they would check it!” Maybe! But I worked for the government for 32 years, and if you think you can rely on what some government guy said one day, I have news for you. Maybe NOT that reliable. Better verify, repeatedly and over time.

    Surely everyone knows plants do not — can not, and have never — created an element, right? Elements can not be created. Iodine is an element. It would have to be in the ground FIRST, and the plant roots pick it up.

    I would love to learn more, I just have questions and doubts. It seems dubious to me that we rest our health on the supposition that this plant has these things. Maybe they DO. But if it’s important enough to focus on, would it not be important enough to make sure that’s correct?

  16. The health ranger tested a lot (if not all commonly eaten) sea veggies & only one brand did not have heavy metals in It! I think Dr. Gregor may want to check more into this before recommending to eat these for iodine.

  17. I choose to get my iodine from supplements. Can I take 350 mcg 3 times a week (like on Monday, Wednesday and Friday)? Weightwise that’s equivalent to 150 mcg per day.

  18. Do we need iodine consumption every day because other elements in the halide family (chlorine, fluorine, bromine, etc) keep displacing iodine out of the body? Can’t the body recycle iodine?

  19. Hi, Arthur! You ask some really challenging questions. Yes, iodine is recycled in the thyroid. It is also stored. There are some genetic and other conditions that could cause a person have impaired or missing deiodinase enzyme activity needed to remove iodine from storage in thyroglobulin. Those persons probably do need iodine every day. Most people do not necessarily need iodine every day, as long as regular intake is sufficient to maintain adequate stores. It is important to note that vitamin A, selenium, and iron intakes also need to be sufficient, because deficiency in these nutrients can make the effects of iodine deficiency worse. I did not find credible data to support the idea that other halogens displace iodine from the body. Please be aware that too much iodine can be as harmful as too little. The RDA for iodine is 150 mcg per day for adults, and intake should not exceed 1,100 mcg per day. I hope that helps!

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