Doctor's Note

Other videos on iodine include:

For more on the health benefits of seaweed, see Which Seaweed is Most Protective Against Breast Cancer?

For further context, check out my associated blog posts: Do Eden Beans Have Too Much Iodine? and Nutmeg Toxicity.

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  • JJ

    I have watched all five volumes of your DVDs, but it is a lot of information and I don’t have it all memorized. I know that you have a video somewhere about kombu, but I couldn’t find it on this site. So, I’m hoping it is OK to ask the question here under this video which is related:

    I thought I remember you saying that we should stay away from kombu because it has too much iodine? I like to put a sheet of kombu (maybe a 2 by 4 inch sheet) into pots of grains and beans that I cook. Mostly I throw away the kombu that is left at the end and eat the grains over the course of a week. So, would I be getting too much iodine if I do that?

    Also, sometimes I actually like to just snack on nori. But the nori goes down pretty fast. I give some to my dog, but most of it ends up in me. How many sheets would be too much in a sitting? In a week?

    (And fyi: a search on your site for Kombu turned up nothing – except for the kombuchi tea. Also, a search on nori turned up nothing. I do hope that lots of key words will be added to the videos.)

    Thanks for any guidance you can provide on kombu and nori. I want to get the iodine from food if I can, but I’m struggling to figure out how to get just the right amount (not too much or too little) easily.

    • Michael Greger M.D.

      What an opportune time for this question–I’m actually going to posting about Kombu on Friday–stay tuned. I’m so glad you got so much out of my DVDs (all proceeds to charity).

      • JJ

        re: “I’m so glad you got so much out of my DVDs…” YES! I highly recommend the DVDs to people. This website is wonderful because people can see individual videos on-demand and because of the interactive nature of this site.

        However, seeing a video-here, a video-there does not give one the big picture. By seeing all the videos together and in order, one starts to see a pattern that is compelling. To people reading this: Go get those DVDs and show them to your whole family! And then to anyone else you care about.

    • Pikurasa

      Hello, I would also like to know the answer to this question. My wife is Japanese and frequently uses Konbu to make a nice broth for the soup. I have sometimes eaten this up, which I will now stop doing (I am probably good on my iodine for like 10 years now), but is the amount of iodine in the broth at a dangerous level?

  • Karen LaVine

    FYI: I have submitted an email question to Maine SeaCoast Vegetables re: some apparently incorrect information on the nutrition facts label on their Laver. The bag pictured in this video is labeled as containing 1 oz, not 2 oz, yet the label on the back of the bag says it contains 8 7gm servings. I’ll update when I hear back from them. Nevertheless, I am planning on purchasing some Laver to get my iodine from a nutritious whole food instead of from a supplement.

  • Eric Needs

    I love you

    • Cara

      Yes, we all love Dr. Greger!

  • wickedchicken

    I am just wondering, considering the massive contamination of fish in the sea all over the world [even the Antarctic as you said!], surely seaweed is also contaminated too? It is …from the same sea after all. Any evidence-based thoughts?!!!

    • Thea

      wickedchicken: I don’t know the answer to your question as a fact, but I have some ideas that you might consider:

      1) Dr. Greger has one or more videos on this site that talk about contaminates getting concentrated the further one moves up the food chain. So, even if there are some contaminates in sea plants/seaweeds, there would be a lot more in sea animals. You should generally be able to greatly minimize exposure by sticking to the plants. In other words, it would not be appropriate to equate the two just because there might be some contaminates in seaweed.

      2) While there is sea contamination all over the world, it is probably not true that there is equal contamination in every part of the sea all over the world. Think about our air: Yes, the planet shares air. However, some cities have a lot more polluted air than others. Also, we know from Dr. Greger’s videos that some sea plants just seem to suck up the contaminants while others are not as bad.

  • chrifou

    Hi Dr Gregger,
    I use half a teaspoon of agar-agar powder in 946 ml of soymilk to make my yogurt. Unfortunatly, I was unable to find the iodine content of agar-agar. Should I stop using agar-agar until until the iodine content is known ?

  • DrDons

    Hi Chrifou, Agar-agar is a mixture of two polymers derived from red algae and should not contain iodine. So I would continue using the product.

  • PabloC

    Dear Dr. Greger:
    I live in Chile, and here I haven’t seen any of those seaweeds… ¿What about Nori and cochayuyo (durvillaea antarctica)?
    Thank you!

  • traxmom

    So how big ARE those bags of sea vegetables in your video?

    • PabloC

      I hear these are 2 ounce bags.

  • adah

    wow, thanks – this is new information to me. i probably am way overdosed on kombu kelp and hijiki – are we concerned even about organic and sustainably harvested hijiki that i get from small scale operations like natural food coop? too bad, it’s a nice sea veg in miso soups

  • Jola

    How does this guidance apply to someone who has Hashimoto’s Thyroiditis and is taking Levothyroxine on a daily basis? Same guidelines?  I’d really hate to limit my intake of flax, broccoli, cabbages, etc.

    •  Since you are taking a thyroid supplement you don’t need to worry since the supplemental hormone already contains the iodine. So you should be able to consume the flax, broccoli, cabbage etc. There are other chemicals in the environment that can affect your glands see… Of course you will need to get your thyroid level checked periodically and work with your physician to make sure you are taking enough and not too much. 

      • Jola

        Thank you, Dr. Forrester. I really appreciate your response.  I had no idea that my Levothyroxine contained iodine. 

      • Rebecca Morris

        Dr. Forrester, I also have Hashimoto’s and take a thyroid supplement (Thyrolar, which contains both T3 and T4 since my body does not do the conversion well). If I start eating seaweed, is this likely to have an impact on the Thyrolar dosage requirements? This is especially important for me because the standard thyroid tests do not seem to measure my thyroid levels accurately … (I’m told by my endocrinologist that this is true for about 1/3 of thyroid patients) … so I want to anticipate any possible problems rather than try to diagnose them later. Thank you.

  • Michael Greger M.D.

    Please also check out my associated blog post Do Eden Beans Have Too Much Iodine?

  • Vegandaoist

    As for the arsenic, would that not depend on the source and lo0cation? Is arsenic in all ocean water all over the world and why would this one sea veggie suck up arsenic and the others do not?

  • Here’s something to ponder on. Most people today get iodine from iodized salt, milk and fish. Vegans can get it from seaweed. I got thinking about when we were evolving. We didn’t always live by the sea so where did we get our iodine? Where do other primates get their iodine? Are their needs less perhaps?

    • Toxins

       Iodine is naturally occurring in plant foods in small amounts due to extraction from the soil. Current iodine levels in the soil due to current farm practices are near zero.

    • Occams_Razor

      Soil in some areas used to be undersea in previous geological ages, and has iodine in the soil.

  • mbglife

    With regards to being too iodine laden, I buy an inexpensive shaker of kelp at the health-food store of Main Coast brand’s Sea Seasonings. They tell you on the label that just 1/4 teaspoon (note: not tablespoon) is 20 times the RDA serving. So I take measure out a few little shakes on a spoon that looks about 1/20 of a 1/4 tsp and then I don’t have to worry about it.

    This isn’t much of a bother, but the reason I choose this over other methods is that while I like sheets of seaweed, they give me reflux and/or diarrhea. And I don’t like the more measured supplements because of all the added “stuff”. After just a few times of doing this I’m pretty used to what a few sprinkles should look like, so I think I am getting the right amount each time.

    Still, having said all that, I would love it if I could get a little measuring spoon, like some of those horrid little sweeteners have, that gives you a tiny but precise amount. If anyone has a recommendation for where to buy a scoop that is .0125 of a teaspoon (1/20 x 1/4), I’d love to hear the suggestion.

    • Did you ever find a tiny scoop? I recently bought some kelp powder to try out. Previously I have used Lugol’s solution for iodine. Instead of sprinkling a small amount on food I’m considering mixing 1/4 tsp of kelp powder with 1L of water then spread that water out over time drinking 50ml each day.

    • Danielle

      I contacted Maine Coast sea vegetables and they say that “Kelp Blend Granules has approximately 1450 mcg in 1 teaspoon. ¼ of a teaspoon may have as much as 362 mcg!”

      So half a 1/4 teaspoon is 181 mcg which is the RDA.

      The amount of Iodine for a healthy adult should be 150 mcg so you’re right there with 1/8 of Kelp.

      Where did you get your information? This info is directly from Maine Coast! Thanks just curious!

  • Sam

    I am thoroughly confused about eating goitrogens. A few
    years ago, my TSH tested at the upper ranges of normal. I chose to lower it to
    an optimal (less than 2.0) level by taking Armour thyroid. I have found that
    the foods that make up most of my diet—cruciferous veggies, soy nuts,
    strawberries, almonds, peanut butter, sweet potatoes, and spinach—are the foods I am supposed to avoid. I understand that it is beneficial to eat them cooked, but should I avoid them? That is a lot of nutritious food to exclude. If I
    avoided these foods, would my TSH be lower on its own (without Armour?) Should I continue to eat those foods, but take Iodoral? Help!

    • You need to maintain an adequate iodine intake and iodoral is a good choice if you are not consuming any iodized salt. See Dr. Greger’s video on goitrogens… Even moderate intake of raw goitrogens are okay if in moderation… you can overdo just about anything including iodine… see As far as the diagnosis of low thyroid it is sometimes a challenge. Medical recommendations seem to always be lowering the treatment thresholds. It would be helpful to have baseline levels for individuals to check for the need for medication. The reality is the blood markers need to be evaluated in conjunction with symptoms so it is important to work with a knowledgeable physician.

  • maya

    Dr. Greger does not recommend Kelp as a good source of Iodine, however, what about the supplements at the store that are Kelp based. I think I looked at the nutritional info on the bottle and it was 600 mcg per dose which is about in the middle of Dr. Greger’s and the WHO recommendations. Another issue I’m confused about is that some of the companies are recommending that IODIDE be present in the supplement for better assimilation…is this a factor to consider while trying to choose a good supplement?

  • Daniel

    Get the Maine Coast dusle granules instead, they have about 300-350 mcg of iodine per teaspoon so you can measure a lot more easily.
    I’ead that the Japanese have around 5-10 mg of iodine a day, which is well over the upper limit of 1 mg. They don’t seem to have any problems. Shouldn’t this mean that the upper limit should be increased? Why is that amount of iodine ok for them but not for anyone else?

  • limor

    My mother (61 y.o) had a Subtotal Thyroidectomy in 1992 due
    to Papillary Carcinoma and had a radioactive therapy (I131). Since then and to this day she takes Eltroxine and the TSH is about 0.05. In 2010 she was diagnosed with recurrent tumor
    size 12 mm that wasn’t change in follow up U.S.
    I wonder if she can eat the broccoli family and other goitrogenic food? In
    addition, can she eat food that contain Iodine?

    • laloutre

      I saw Dr Greger this morning at a conference in Montreal and told him about my thyroid cancer (i had a total thyroidectomy last december) and asked him if i should avoid cruciferous vegetables or soy. His answer was that there is no problem as lon as i make sure to eat enough iodine.

      I wanted to ask him after the conference how much iodine someone with no thyroid should eat. Is it the same amount as someone with their thyroid, but i didn’t have the chance to ask him.

      Dr Greger, if you read this could you please give more information about this?

  • Gen Collett

    then explain asians that eat alot of seaweed?

  • suzy

    Hi, I have hypothyroidism but am not taking any meds. My bloods are always within normal range, but I strugglt to lose weight, have very dry skin, eyebrows have gone on outer edges, have carpal tunnel and fatigue etc etc. I have recently changed to a vegan diet and eat plenty of kale, saur kraut, broccoli, cauliflower and nuts, among other foods. Advice please on what is good for natural treatment of hypothyroidism.

    • Mery Daae

      did you gauge any info on this? same boat here! thanks!

  • Wakame I really like. I just wonder what would be an ok daily amount. If the bag would last two months… hm… very small piece I think?

  • Jodi

    What about trans-dermal application of iodine? Does “painting” Lugol’s on your skin help with eliminating a deficit, not necessarily maintaining a balance? Does evaporation time of iodine on skin indicate deficiency, or lack of? Is selenium required to help with iodine absorption, as found in one Brazilian nut?

  • Amy

    Hey there,

    I was just wondering if for this recommended daily amount we must eat it daily or if we can just eat the daily amount all added up once per week etc. I guess this question extends to daily amounts in general.

  • Bella2

    A concerned Vegan…

    Dr. Greger,

    I love your site and watch your YouTube videos constantly –

    Thank you for the work that you do and the information that you provide to we who do not trust in the medical industry’s current philosophy – “Don’t Cure Disease, Treat It. No money in curing disease”.

    Now, my query –

    I am absolutely Vegan – even to a point of no sugar, no white flour or white potatoes, only use a trace of oils – and have been for 6 months…

    However, I just had a lipid panel completed and my Cholesterol is a whopping total of 222 (LDL 125, HDL 85, and triglycerids 61). I do have an elevated Thyroid level at 3.2 (desired range 0.3-3.0).

    I briskly walk 6+ miles a day and spend an hour in the gym.

    Is there any reason to be concerned over these numbers?
    Does an elevated Thyroid have an affect on Cholesterol levels?
    Is there anything else I should be doing to reduce my cholesterol?

    Thanks again for what you do.


    • Hypothyroidism can absolutely raise your cholesterol levels. I’d get it treated and then recheck. Thanks for your question!

      • Bella2

        Thank you so much for responding… I love watching your videos. They are funny yet so so informative. I do have to say i have been on meds for my thyroid it was levoxyl 50 mcg. When it was recalled a fews month back I started taking synthroid 50 mcg it was so strong I cut the dose in half to 25 mcg a day…. I have now started back on the 50 mcg and I am going to start taking CholestOff 2 grams a day and hopefully this will be enough to drop the LDL and Total Cholesterol. Thanks again for caring Mary

  • DontGetIt

    Why isn’t there more clinical studies on iodine supplements such as lugors? There’s a whole subculture of folks taking large doses of iodine, both on their own and with Dr.s supervision to cleanse themselves of bromine, flourine, chlorine. Is this really an issue? Sure wish there was a more definitive study of iodine’s efficacy as a supplement.

    • John

      Do a web search on Dr. Brownstein. He is one of the iodine experts. He’s been treating people for years with iodine.

      I take 25-50mg of lugols every day. My cholesterol dropped 40 points without changing my diet(I have a plant based diet). I feel more alert taking iodine. Iodine is like a plant based diet, the medical community doesn’t make any money off it.

      There’s no money in healthy and dead people. Sick people make the medical community wealthy. There’s no financial incentive for doctors to get people well.

      If you watch Greger’s videos than you are probably more informed about the health benefits of nutrition than most docs.

      BTW, seaweed has bromide in it. Take lugols.

  • Ronald Chavin

    (1)Wakame has no English name. Alaria is a brown seaweed in genus Alaria but wakame is a brown seaweed in genus Undaria. They have both been placed in family Alariaceae, order Laminariales, class Phaeophyceae, division Heterokontophyta, kingdom Chromalveolata. Technically, brown seaweeds such as kombu (kelp), arame (kelp), limu moui (kelp), mozuku, hijiki, and wakame are NOT plants (in kingdom Plantae). However, red seaweeds such as nori (laver), ogo (limu), and dulse are plants (placed inside of kingdom Plantae):

    (2)According to the following study, “When kombu is boiled in water for 15 minutes, it can lose up to 99% of its iodine content….”

    (3)According to the Linus Pauling Institute, a very high intake of iodine will slightly increase our risk of developing thyroid papillary cancers but slightly decrease our risk of developing thyroid follicular cancers. Thyroid papillary cancers are less aggressive and have a better prognosis than thyroid follicular cancers:

    (4)The Japanese in Japan who eat high-iodine brown seaweeds raw (uncooked) tend to have lower total cancer rates compared to Japanese in Japan who eat high-iodine brown seaweeds boiled (much lower in iodine):
    Apparently, this lower cancer rate among raw seaweed eaters can be explained by: (a)the good saltwater bacteria from the ocean, which provide an enzyme which allows humans to digest the polysaccharides in seaweeds, (b)the phyconutrients in brown seaweeds, (c)the phytonutrients in red seaweeds, and (d)the iodine, which like zinc and selenium, is a beneficial antioxidant.

  • Dar

    I’ve seen seaweed sold at Costco but it didn’t list the type of seaweed. Ingredients just list ‘seaweed’. Should this be avoided since it might be kelp? Also, last year my cat died as a result of hyperthyroidism. Since you put out this video, I noticed that a lot of cat and dog food contain dried kelp as an ingredient. I would think that someone in the veterinary world would have made a connection and found another source for iodine.

  • Rob Di Censo

    Would high doses of kelp be good for someone who has thyroid deficiencies?

  • Tony

    Should we be worried about radioactive iodine in seaweed, for example, from Fukushima?

  • Georgina

    I just got 100g of kelp powder from the health food store! Considering sprinkling it over my garden now! I also put a 1/4tsp of it in my breakfast porridge. It tasted a bit nasty, but forced it down because i thought it was good for me…wrong!

  • Brent N

    Dr. Greger, this was very informative and I enjoy your data-driven videos. Do you have any information on the seaweed Bladderwrack as to the iodine content?

  • Beth P

    What about other sea contaminants, such as mercury found in fish? Do these sea vegetables also soak up those?

  • Kartoffelmao
  • Chelsie Beck

    I have also read that cranberries are a great source of iodine. Is this true?

    • kimhis

      I did a simple search of ‘cranberry iodine’, and found 4 ounces of raw cranberries to contain about 400 mcg of some sort of iodine. There was no mention of whether these were coastal grown berries or what. And who eats raw cranberries?

    • Cheryl Hugle

      My endocrinologist told me the same thing and I just found this:
      (The same site also mentions that potato skins are an excellent source of iodine.)


      Cranberries have a rich color and a unique flavor. If you’re able to
      enjoy the sour taste, cranberries provide many health benefits. They
      have a high concentration of Vitamin C, Vitamin K, and fiber, and
      they’re known to prevent urinary tract infections. They’re also a
      stellar source of iodine; four ounces of these tart treats contains well
      over the recommended daily value of iodine.

      Serving Size (4 ounces), 400 micrograms of iodine (267% DV), 52 calories.

  • Luz Maria

    I am a vegan with vegan children. If i were to use himalayan salt in my cooking would that be enough to avoid an iodine deficiency?

    • Thea

      Luz: How wonderful to hear of another vegan family! Your children are so lucky to have a mom like you who gets it. I sure wish I had been vegan growing up.

      I’m not an expert on the matter of salt, but I have done my own research in the past. I don’t know how valid it is, but I was left with the impression that you can not rely on “natural” salts for sufficient iodine intake. There is either not enough and/or the amount is not consistent. If it were me, I would want to make sure my family got a reliable source of the right amount of iodine.

      Good luck.

  • Jordan

    “Until nearly five years ago, Americans who got dairy, bread, and meat in their diets got plenty of iodine, he explains. Machines used in production were cleaned with an iodine disinfecting solution, so some iodine ended up in dairy, bread, meat products. That ended when companies quit using iodine disinfectant.

    Iodized salt is rarely found in canned, frozen, or boxed food, says Maberly. French fries and other snack foods mostly contain regular salt — not iodized salt.”


  • Derrek

    Would about kelp if the concentration is controlled? I found some kelp: Iodine
    270 mcg

    (Laminaria digitata & ascophyllum nodosum)

    It has 2 scoops and lots of servings for cheap. Is that ok?

  • Dina

    Hypothyroid Questions

    I gave been a vegetarian for 17 years and a vegan for just 10 months. I was hyperthyroid in my teens and twenties and took oral medication, the name of which I don’t remember. My thyroid levels were normal in my 30s and 40s with no medication. I became hypothyroid in my 50s and now 60s. My doctor has tried me on synthroid, levothyroxin, and now, with the most success, armor thyroid. It really bothers me that this is from pigs. So, finally to my questions.

    Can hypothyroid disease be reversed to a point where no medication is needed?
    Am I getting all of the awful effects of eating pork by taking this pill?
    I have low blood pressure and now salt (iodized) my food (I don’t eat processed food) more now than I used to, which is still not very much. Is this a good idea?
    I tried nori, but noticed that the little packet of desiccant in the packages are lye. Yikes!

    I’m know that you can’t give specific medical advice to me, but I have watched you videos on thyroid, pork, animal protein, etc. and would be interested to hear any research related to my questions.

    Love your videos!!!
    Westlake, Ohio

  • thaicoffee

    I need iodine and don’t use enough salt to make it worthwhile. Like many folks who grew up on the ocean and learned to body-surf badly at a young age – I refuse to eat sea weed. I have tried to like it – I really have. It always tastes like drowning to me. Most of the sea weed I have eaten in my life has been involuntary while have my face ground into the sand and trying to figure out which direction the air is when a wave is crashing on me. So….no, No NO on sea weed. Could I please have some useful information on supplements, requirements, liquid or tablet – that sort of thing. I am already hypothyroid likely from iodine deficiency but sea weed is just not going to happen. I will go back to fish first. Please help.

  • Guest

    In Japan the serving/portion of Wakame, is only about 5 grams per person (per soup bowl) in Miso soup, or in other Japanese dishes using Wakame, the normal serving size per person is only about a handful, enough to fill a small serving dish/bowl. A little bit of a wide variety of food is served daily, and eaten often. Wakame is also good for keeping you regular.
    As to Konbu, only a 15 x 15 cm sheet is used to make broth, it is soaked for 30mins then simmered, removed before boiling point, and the actual konbu sheet is not consumed. Unfortunately nowadays a lot of packaged “instant” broth powder is used (with additives etc) instead of making the broth from scratch.
    I hope this helps people who are wondering about the portions.

  • Jordan

    Ok i need some good help here, im thoroughly confused. I’m 26 5’6″ 114 lbs, In generally well health, I’m currently on a Vegan Diet. I was taking 1g of Seaweed for Iodine supplement since i DO NOT use Iodized salt. Back when i was eating iodized salt My T4 was 1.000 ng/dl. My TSH Level was 2.22 ng/dl.

    I recently stopped supplementation as advised by my Dr. since the idea was i eat enough prepackaged foods to provide enough iodine.(and from the research i found prepackaged foods in the USA are largely using Non-Iodized salt. please see sources below.) So after 4 weeks of No Iodine supplementation either from sea weed or from added iodized salt. Now my T4 is 1.11 ng/dl. and my TSH is 3.99 ng/dl.

    So what is going on? Should I take Iodine supplementation or not, and if not where am i getting my iodine? Im so confused and this causes me lots of worry anyone that knows what they are talking about let me know what you think. btw the standard ranges are below as well as sources to support my statements.

    Standard Ranges:
    TSH 0.34-4.82 uIU/mL

    FREE, T4 0.76-1.46 ng/dl

    “Processed foods, however, such as canned soups, almost never contain iodized salt.” [1]

    “Although iodized salt is a principal source of dietary iodine, suggesting that reduced salt intake could lead to iodine deficiency, the salt in most processed foods in the United States is not iodized “[2]

    “Most of the sodium in the American diet comes from prepared or processed food, and most food companies don’t use iodized salt. “[3]

    “3.2 North America.

    In the USA, iodization is permitted on a voluntary basis at a level of 77ppm as KI, however,

    virtually none of the salt sold to food processors is iodized. “[4]






  • Brock Leham

    I use “sea seasoning” kelp granulates. 1 tsp = 900% RDV, so I just sprinkle 1/8 tsp in my shake. :-)

    It’s tough to get sea veggies around here…

  • Faizah Wehbi Downing

    What about Himalayan Pink Salt?? Can that replace Iodized Salt? And how many tsp a day?

    • Thea

      Faizah: From what I have read, the “natural” salts contain only trace amounts of minerals, and you can’t count on any specific amount of mineral being in any particular batch. So, I wouldn’t count on the Himalayan pink salt for being anything other than salt.

      That’s just what I read. I don’t know it for a fact. But for something so important, I would want to be sure before I relied on a particular food for a vital nutrient.

    • Toxins

      Sea salt typically does not contain iodine unless it is fortified with it.

      • Youcef

        And when it’s fortified, it’s usually written, at least in Europe.

  • Violet

    Dr. Gregor or NF Team,

    Could you possibly make a quick edit to this video so that the amounts of seaweed in the packages are shown? Saying “this much” contains a month’s worth (etc) of iodine is more helpful if we actually know what that “this much” is.

    Thank you for all the great information and videos.

    • Youcef

      An edit is actually much needed since Dulse and Wakame from that brand actually have very similar iodine concentrations are both equivalent to two months
      @disqus_EXJURIXKLQ:disqus @Toxins:disqus could you correct the “one month supply” to “two months” ?
      Dulse 780% DV per serving (7g) * 8 servings per 2oz (56g) pack
      Wakame 770% DV per serving (7g) * 8 servings per 2oz (56g) pack
      See iherb links and pictures :

      • Thea

        Youcef: Neither Toxins nor I have the power to change the videos or scripts. But I believe Dr. Greger tries to read every comment. And when he is able, I believe he tries to post corrections when warranted.

        Thanks for your post/links. I still find this topic very interesting and often on my mind. I appreciate any info I can get.

  • Youcef

    Here’s a heavy metal analysis of a few seaweed brands :
    I wish the video commenter went straighter to the point (30 minutes with sparse useful extra information), but you can get the website name and go straight to it. Enjoy :)

  • Anestassia

    Is it true that we can get over 200% the RDI of Iodine just from a single serving of cranberries?

    • Cheile61

      Would also like to know this as I noticed improvements when I made myself some fresh cranberry juice but A: I’m not keen on it: B: it’s an expensive source, C: I can’t find and wouldn’t want to pay out for organic cranberries really!

  • Bruce Cropley

    Hi. I came across this claim that seaweed products contain high levels of mercury. This isn’t exactly a scientific study link, but I’m wondering what your opinion is about it anyway:


    Bruce :)

  • discoteque

    I haven’s seen anybody ask this. But is there a mistake on the video?

    According to Nutrition Facts on Maine Coast Kelp it has 2110% of iodine per 7 g. (
    56g per pack = 16880% or for 169 days. Which is close to half a year but not 5 years of supply.

  • Asha

    what about spiraling? Is that a good source of iodine, I usually do it in smoothies, and how long will it last compared to other sea vegetables?

  • Asha

    What about spirulina? Is that a good source of iodine? If so, how many times a week should it be consumed?

  • Tobias Brown

    Where does arame seaweed fit on this list?

  • Tobias Brown

    A quarter gram of kelp is too much? Arame is a type of kelp. It seems that people eat fairly large quantities of this when it’s consumed. So, are they thereby eating dangerous amounts of iodine?

  • Sandra

    What about Arame — one of my favorites? Good, bad, indifferent? Thanks! ;)

  • Réflexonat

    Hello Dr. Greger,

    Are those bags 2 OZ ? Please let us know.

    And Thanks for all the work. Your help is fantastic.

  • Richard Wade
  • DiegoWks

    Do you take kelp in powder or tablets ? and the dose please maybe if you have de “g” of the tablets can be helpfull for me

  • Blaice

    If you eat 0.2 grams or less of kelp a day, wouldn’t it be fine to use as an iodine supplement? Or am I missing something? I’m not particularly fond of sea vegetable tastes, nor is my girlfriend, but I feel like taking a tiny pinky size piece from a dried sheet of kelp would be super easy, and still be right around the daily recommended intake for iodine. Am I missing something here?

    • Thea

      I’ve often wondered the same thing. For what it’s worth, here’s my thought: what if the iodine is not evenly distributed? What if some batches are more than others. What if the ends have more or less iodine compared to the part you pinched? When you start talking about taking such small amounts, what if you aren’t really getting the amount of iodine that you think you should are getting? I have no idea if this is a legitimate concern or not. I’m just sharing the thought.

      I have often sprinkled *tiny* amounts of kelp powder in my oatmeal, hoping that this would do the trick. I enjoy nori, but I’m not consistent about eating it. But adding an imperceptible amount of kelp powder to my oatmeal is no hardship. Even though I do it, I have to wonder: am I really doing myself any good?

      I’ll be curious to hear what other answers you get.

    • george

      BlaiCe: You can buy kelp tablets containing a constant and known amount of iodine, which eliminates the guesswork.

      • Blaice

        Ha, that would be handy if I hand’t bought dried kelp about half a year ago. I take half a pinkie size pieces though, so I’m not worried. Especially because it’s my main source of iodine other than potatoes, and cranberries when in season (not often).

  • Ups, it isn’t a good feeling when you recognize by your self that the intake of iodine isn’t enough… suddenly my brain was working slowly, I ‘m struggling for some words. It can be very frightening. Ok, god pleas you Mister Greger for this article. But there is still a question inside me.
    is the thought right, that I should take more then the recommend daily intake of 160 micrograms for a while now until the hidden reserves are full again, because I need the daily intake plus that was is going into the reserves or does my brain still not yet working very well again?
    Here in Germany I can take a Wakame soup, each portion has approximately 338 micrograms iodine inside, according to the labor test. good or not Good to take it daily?

  • Ringer

    Hi Dr. Greger. Thank you for your great and informative videos! I recently had a blood test done and everything was fine except that my doctor was concerns about a slightly under active Thyroid result. She said to do nothing except come back to her in two months to check it again but I was going to try to introduce more Nori to my diet to see if that helps with my fatigue. How long do you expect it takes to regain an normal thyroid function going by your suggested intake of sea vegetables in the above video?

    • Thea

      Ringer: I’m not an expert, but for what it’s worth, I think you are very wise to try to add some nori or other sea vegetable to your diet. I’m guessing we won’t know how long it would take to kick in for you, but it certainly can’t hurt to try for at least the two months your doctor wants you to wait and come back. As Dr. Greger is often saying, there’s no downside to trying adding a whole food to your diet in recommended amounts. Good luck. Let us know what happens.

      • Ringer

        Thanks so much Thea. Hopefully introducing a little be more sea vegetables into my diet will do the trick!

  • Cheile61

    Hi guys I have a few questions, not sure if they’ve been answered all ready..

    1. I’m on a budget and think I’m missing Iodine. I started eating quite a lot of mackerel a while ago and felt better so continued but I think I was over consuming and since learning about how bad toxicity is, and suffering brain fog I wondered if I was getting metal toxicity.. so I want to take seaweed or supplements but wonder if lugols or tablets are better / more affordable?

    2. I can buy some dulse for about £7-8 for 100g here in the UK which isn’t too bad I think, it would be about 75-100 days supply at around 150-200mg daily I think (v rough calculation) but supplements or lugols seem like they could be cheaper, and perhaps especially if one was needing more iodine than 200mg.

    3. What are your personal experiences? Do you find 150mg is enough? does a safe limit vary for smaller body mass? I’m pretty small of stature.


  • Cheile61

    Hi guys I have a few questions, not sure if they’ve been answered all ready..

    1. I’m on a budget and think I’m missing Iodine. I started eating quite a lot of mackerel a while ago and felt better so continued but I think I was over consuming and since learning about how bad toxicity is, and suffering brain fog I wondered if I was getting metal toxicity.. so I want to take seaweed or supplements but wonder if lugols or tablets are better / more affordable?

    2. I can buy some dulse for about £7-8 for 100g here in the UK which isn’t too bad I think, it would be about 75-100 days supply at around 150-200mg daily I think (v rough calculation) but supplements or lugols seem like they could be cheaper, and perhaps especially if one was needing more iodine than 200mg.

    3. What are your personal experiences? Do you find 150mg is enough? does a safe limit vary for smaller body mass? I’m pretty small of stature.

    The site I’m looking at says an entire 100g bag of dulse contains only between 15-55mg of Iodine, which is less than a days supply, conflicting with the information in this video. Can anyone clarify? Are the estimates wrong? I think I’ll go with Wakame (alaria) as I know it has a higher Iodine content.

    The NHS states: (Not that I believe them really..)

    Adults need 0.14mg of iodine a day.

    Most people should be able to get all the iodine they need by eating a varied and balanced diet.

    Helpful as always; am I hearing correctly; 150 mg a day at least? that’s exponentially more than 0.14 mg or am I missing something?? Confused!

    • Gatherer

      You are confusing milligrams (mg) with micrograms (mcg). There are 1000 micrograms in 1 milligram. Micro is usually written as the Greek letter mu, but not all fonts have Greek letters so “mc” is often used. The recommended daily dose of iodine is 150 micrograms per day. 150 mcg is the same as 0.150 mg. 15 mg of iodine would be 100 days worth.

  • AHHHH, please help. I’ve got two important questions, ore three?
    First: If the serum creatinine low can I be sure that the urine creatinine also is low? In Germany the urine creatinine is measured also for the iodine loading in the body. means, if the secretion of creatinine in the urine is high enough the patient has enough iodine in the body… is that right?
    Second: If the store for iodine empty, would it be not logically that the patient has to increase his intake of daily iodine because the body needs about 200 µg plus a little bit to fill up the store again? And then, if the patient is a vegan and konsum every day Dr. Gregers daily dozen with flaxseed and often broccoli would he need even more to fill up the store again? And what about the article I read in a German medical journal that humans only absorb about 40 % of the iodine intake?
    If I calculate right, I think I need for the next time about 400 µg iodine daily or is my conclusion totally wrong?
    My serum creatinine is since 3 years a little bit to low (about 63 mg/dl) and in the last time I developed strange symptoms. The TSH is still all right and so my physician is not worried – but, I’m honestly – I’m not sure he is the best. :-(
    Thanks for much for a helpful answer.

  • Kat Denton

    what about fermented kelp? i have a product that is fermented kelp & chlorella in miso…would this also be detrimental? (i do have hypothyroidism)

  • Poonam Sharma

    Hi! I am from india . I recommend my clients to stop diary and have soy products for healthy weight loss. But i am always doubtful with hypothyroid patients So which food products are good source of iodine . Alaria, Dulse , Laver are not available here. Which are the alternative sources whch we can get in India

    • Hello Poonam Sharma, I’m from Germany and I have to go in a Asia-Shop to get good seaweed. Your country is much nearer to China, Japan or Korea than Germany – havn’t you no shops running by a chinese or japanese people? What about ordering by internet?
      Here in Germany we have also salt with seaweed inside, a little bit you can get from red radish or also called small redish or white mushrooms but I don’t think you can get there in India.

  • Dos anybody knowing whether the information of iodine content on a pack of seaweeds pro 100 g seaweed means dried or mean it fresh? Unfurtenally all my packs are from a japanese factury so I’m not able to ask the factory directly.

  • Marta Sprout

    I’ve been told that we can’t be allergic to iodine and yet when iodine or Betadine is put on my skin I get hives. Before I changed to a plant-based diet I had allergic reactions to shellfish. Any suggestions for getting iodine without an allergic response?

    • Thea

      Marta Sprout: Have you tried some seaweed products? Nori is very tasty… You might also research to find out which foods are particularly high in iodine and tweak your diet to include those foods, such as being sure to include lots of whole grains. You can use that tactic combined with the site,, to see if your intake of iodine is already OK from your natural diet and thus supplementation is not necessary.
      I’m curious if you have a reaction when you eat foods fortified with iodine. Maybe you would be fine with lower iodine concentrations from fortified foods?

  • Tobias Brown

    How much laver or nori seaweed would be recommended given this sodium limit?

  • Tobias Brown

    Does potassium intake relate in some way to sodium intake? Does it make a difference how much potassium we consume?

  • Pam McCoy

    My mom use to put iodine from a bottle on the soles of her feet. Does that work to get iodine?

    • Joan_RN-Educator

      Interesting concept, Pam. I was able to find very little in this non-traditional approach to obtaining iodine.This reference may be helpful:6 selected items – PubMed – NCBI It seems absorbtion of iodine this way involves many barriers, including of course the skin itself. If you have strong iodine exposure to skin you may develop skin irritation. Skin absorption would be very limited evaporating quickly and subject to the thickness of the skin and body’s ability to transport iodine thorughout (as opposed to the much more efficient process nutrient dispersion of digestion. So while you mom’s remedy might seem logical is not practical. Check out Dr. Greger’s video for a more effective way to avoid iodine deficiency,

  • vanrein

    In the Netherlands, our iodized salt (“JoZo” means jodiumzout) contains 21 mcg/g of iodine. With a recommended 150 mcg/d of iodine, this leaves us at the need to consume 7.14 grams of salt per day. Wow. Part of that will be in bread, but it still exceeds the recommended salt intake.

    Wakame appears to be of the same intensity as Kelp, though I’m not sure if it’s the same species. At 7900 mcg/g (for dried Wakame, I’m assuming) its ratio is definately higher than JoZo’s, but we’d need to eat 0.02 grams of it per day. A package of 40 grams should be spread over 2107 person.days or 5.77 person.years. Better get some more people in, because its shelf life is a few months only.

  • Pablo Ramos

    Dr. Greger, could you please tell me what would be your recommendations and / or things to avoid while being a vegetarian with Hashimoto’s Disease? Thanks a Million!

  • Kasper

    Would you recommend using Lugol’s solution as a source of iodine?

  • Kasper

    Would you recommend using Lugol’s solution as a source of iodine?

  • Mr.DonPepinovic

    i´m from germany so please forgive me my bad english! But i need your help! The problem that i have is hypothyroidism. i´m taking medications for 11 years. They are called l-thyroxin in germany. Is it possible to get rid of these pills, because it sickens me that i have to put these chemicals into my body! I also have side effects because of them (bad mood, depression, fatigue etc.). So i would like to try to live without these pills. The question is how should i stop taking them?

    Can you please help me out of my misery?

    KInd regards


  • Dear Mr. Greger and team, I’m a bit confused about the iodine. First of all, there is no official information in german language available about the iodine content in Wakame. So my first question is: Have you got any information about the relative iodine content in Wakame? And if you have, is it the iodine content in dried or fresh Wakame?
    Second question – is there a different requirement between a couch-potato and a ambitious sportsman like me – I tried my bicycle about 300 – 400 km per week during the summer time. Does alcohol consumption, coffee consumption also raise the requirement of iodine or is this a myth ?
    I need urgent some answers because my wife and me have only the seaweed for iodine, because we avoid iodine salt and some industrial junk food (also vegan junk food )…
    Thank you for any support in advance – you can also use this email:

    Have a good week Steffen Jurisch from Germany

  • Susan

    Dr. Greger, I’m a 68 year old great-granny and you saved my life, my mind, and my future! Thank you for your videos. I’m losing my hair here recently, been plant-based for 6-months… Recently started B-12… some days it helps and some days it doesn’t? Before I got bald, can you help me?

  • Protein Deficient

    Is there any other healthy way Not to die from
    iodine deficiency than eating disgusting seaweed or taking supplements?
    This is completely illogical, It is unnatural,
    Most of our ancestors not ate seaweed for lunch, They didn’t supplement iodine also.
    I mean, must be a better way….

  • Jill

    Sea vegetables okay to use by someone with Hashimoto’s? Thoughts?

    • Jill

      Should mention that my thyroid medication does not contain iodine.

    • payoung

      Hi Jill, if you’re not getting iodine in your diet from any other source then sea vegetables should be fine and possibly even helpful with Hashimoto’s. Keep in mind that in Hashimoto’s, the underlying cause of your thyroid disease is autoimmune and you body has produced antibodies against your thyroid gland. That being the case iodine may play less of a role in your case but you still need to meet you’re iodine requirement so as I said, if you’re not getting it anyplace else then a little seaweed shouldn’t hurt.

  • George

    I don’t know if there are better/more recent sources, but the Iodine contents in different seaweed that I found are:
    Seaweed species – Total iodine μg/gDw (mcg/gram dry weight)
    L. digitata 1,886±544
    L. hyperborea 1,946±914
    L. saccharina 1,281±206
    A. nodosum 553±186
    F. serratus 365±31
    F. vesiculosus 494±175
    C. crispus 271±77
    D. sanguinea 110±17
    (source via