Natural Food Sources of Iodine

Posted: March 16, 2011 in Ask The Guyatitian, News, recipes
Tags: , , , , , , , ,

Not surprisingly, in the past few days, I’m getting numerous questions about which foods are a good source of iodine. With recent unfortunate events in Japan, many are concerned about the effects of radiation on their health and are interested in knowing how iodine might help protect against thyroid cancer. Whether we are in any real danger or risk of radiation exposure in the United States today, the truth is, the American diet is lacking iodine anyway.

Why is Iodine so important? Iodine is a mineral that is essential for proper thyroid function. Iodine, when combined with the amino acid tyrosine, produces vital thyroid hormones that control our metabolism, enzyme and protein synthesis, and are essential in the development of the skeletal and central nervous systems of developing fetuses.

Iodine deficiency  Fortification of salt with iodine occurred in 1924 when we were experiencing an epidemic of “goiters” or enlarged thyroid glands. Thyroids become enlarged in an effort to absorb more iodine from the bloodstream. Besides hypothyroidism and goiters, iodine deficiencies have been linked to mental retardation and neurodevelopmental disorders in children, mental and physical impairment in adults, increased risk of thyroid cancer, and some research suggests that there may be a link between iodine deficiency and fibrocystic breast disease.

Food sources  Iodized salt, for the most part, is the main source of iodine in our diet. Table salt usage is decreasing and with our new dietary guidelines encouraging less table salt consumption, we are at risk of inadequate iodine intake. So, where else can we get iodine in the diet?

The present Dietary Reference Intake for most adults is 150 mcg and below is a chart showing the richest food sources to meet that need. Besides iodized salt, you will see that sea vegetables are an amazing source of iodine yet are under utilized as a dietary staple in the United States. The good news is, unlike potassium iodine supplements, it is unlikely that there will be a shortage of sea vegetables anytime in the near future as there is virtually an endless supply in the sea.

So why aren’t more people eating sea vegetables? Truth be told, they taste terrible by themselves. However, made properly, you would be surprised at how good they taste!

 Selected Food Sources of Iodine
Food Approximate
Micrograms (mcg)
per serving
Percent DV*
Seaweed, whole or sheet, 1 g 16 to 2,984 11% to 1,989%
Cod, baked, 3 ounces 99 66%
Yogurt, plain, low-fat, 1 cup 75 50%
Iodized salt, 1.5 g (approx. 1/4 teaspoon) 71 47%
Milk, reduced fat, 1 cup 56 37%
Fish sticks, 3 ounces 54 36%
Bread, white, enriched, 2 slices 45 30%
Fruit cocktail in heavy syrup, canned, 1/2 cup 42 28%
Shrimp, 3 ounces 35 23%
Ice cream, chocolate, 1/2 cup 30 20%
Macaroni, enriched, boiled, 1 cup 27 18%
Egg, 1 large 24 16%
Tuna, canned in oil, drained, 3 ounces 17 11%
Corn, cream style, canned, 1/2 cup 14 9%
Prunes, dried, 5 prunes 13 9%
Cheese, cheddar, 1 ounce 12 8%
Raisin bran cereal, 1 cup 11 7%
Lima beans, mature, boiled, 1/2 cup 8 5%
Apple juice, 1 cup 7 5%
Green peas, frozen, boiled, 1/2 cup 3 2%
Banana, 1 medium 3 2%

*Source:  NIH

*DV = Daily Value. DVs were developed by the U.S. Food and Drug Administration (FDA) to help consumers compare the nutrient contents of products within the context of a total diet. The DV for iodine is 150 mcg for adults and children aged 4 and older. However, the FDA does not require food labels to list iodine content unless a food has been fortified with this nutrient. Foods providing 20% or more of the DV are considered to be high sources of a nutrient.

Photo generously provided by Kok Robin (my sincere apologies for previously omitting this credit)

Kombu is known as the “king of seaweeds” and is one of the richest sources of iodine out of all of the sea vegetables. It is an essential staple in the Japanese diet and is used to make Dashi (stock) and has a wonderful Unami taste. It can also be rehydrated and chopped up and added to stews, soups and casseroles. A strip of it added to a pot of beans, while cooking, reduces gas-producing raffinose.

Here is a traditional Japanese recipe that features kombu called Tsukudani. It is basically a kombu side dish that can be added to rice or eaten by itself. Enjoy!

  • 1 oz. kombu, hydrated
  • 1 tbsp sake
  • 1 tsp rice vinegar
  • 1 tbsp sugar
  • 1 tbsp lite soy sauce
  • 1/2 tsp. toasted sesame oil
  • 1 tsp black or white sesame seeds


Cut rehydrated kombu into thin strips. In a small mixing bowl, place kombu, vinegar and sake in and nix well. Transfer mixture to a saucepan and cover with just enough water to cover. Place a lid on the saucepan and heat to a boil. Reduce and simmer until the kombu is tender. Add sesame oil, soy sauce and sugar. Continue until the liquid has evaporated. Garnish with sesame seeds and serve by itself or with rice.
If you have eaten kombu or other sea vegetables, I’d love to hear preparation suggestions or recipes from you!
  1. Natural Food Sources of Iodine « David Grotto's Nutrition Housecall…

    Here at World Spinner we are debating the same thing……

    • uponmyword says:

      Thank you! An excuse to eat more sushi.

      • Donna says:

        No don’t ! Radiation from Japan’s Fukushima nuclear disaster has been detected in the air in five Western states and in rainwater in at least two so far. The fish are all contaminated!

    • Julie says:

      I always thought that white potatoes were a good source of iodine, have I been mistaken?

      • Naomi says:

        Just make sure your sushi is from the Atlantic and you’ll be fine. Just b/c it’s sushi in America doesn’t mean it’s from Japan. lol.

  2. Add Japanese kombu (I use a 2-3″square piece) to the water when you cook beans to make them more digestible and neutralize their gas-producing effect.

  3. guyatitian says:

    Thanks, Sharon for the extra tidbit – great advice! If you follow what Sharon suggests you should be able to say “Bean there, done that.” Sorry – couldn’t resist!


  4. […] Grotto, author of 101 Optimal Life Foods, has written a blog about the best natural food sources of iodine. For more information, click here. […]

  5. Thanks for sharing David. I am big into peas and ice cream so I will just increase my intake of them for now. 🙂

  6. Good post Dave. For patients undergoing iodine radiation therapy for thyroid cancer, I’m sure they will find this useful as well. Interestingly, I discovered that processed foods actually do NOT use iodized salt. It’s some sort of FDA law I believe. I learned that from the nice folks at Campbell (you know, the soup people) during a media training. I think that many of the iodine content tables being distributed in Dr.s offices may be outdate, just a heads up to readers out there.

  7. Mary-Lou Whitaker says:

    I wondered about processed foods using iodized salt.. . I know when doing home canning you are told to use plain salt and not to use iodized salt. Canning salt is not iodized. I do not know why this is but have been taught this from the my first experience with canning.

  8. flyingcuttlefish says:

    This is a great article!!
    I am posting a link!

  9. Robin says:

    Thank you for fixing it. 🙂

  10. I like your chart that has the food sources of iodine. And, I’m sure it helps a lot of people to know what kombu looks like. I have used it with beans before. I think it improves the flavor. I will let my friends know that it also helps with gas. Thanks to your post. I have learned a lot.

    I’m surprised that white bread has iodine. How did that happen? Wouldn’t whole grain bread be a better choice? Maybe, it indicates that iodized salt has been added.

    • Gipper says:

      It is my understanding that all breads, at least in the US and Canada, have replaced iodine with BROMIDE…which, in my opinion is not a good thing. Comments anyone…please?

      • space says:

        It is true. Bromide is a cheaper and non effective iodine like supplement that ironically blocks iodine from being absorbed. It has replaced the addition of iodine in most foods though.

    • Melissa says:

      Probably because they use enriched flours, I think. He probably means breads like Franz, or Wonderbread, the highly processed non-organic/natural kind. Just read ingredients, if it says “enriched flour” it probably has iodine in it, if not then probably little to none.

  11. Jean says:

    Sorry but the diet in the US is NOT lacking in iodine. In fact, according to the World Health Organization, the US show risk from excess iodine intake which suggests over consumption of foods fortified in iodine, like salt.
    Excess iodine intake can in fact be toxic.. I would strongly suggest to read:
    an easy map is available here too:

    • jeremy says:

      so out of 374 6-11 year olds for the sample size tested in 2001-2002 you feel you can make that broad statement about everyone in the United States? Those children are more likely to get iodine than other demographics in the population. The test for Iodine concentration in the urine is hardly done by doctors, it is certainly not routine. The only salt fortified with iodine is table salt you buy. No fast food uses iodine fortified salt. The reason the WHO has decreased the countries with salt deficiencies is iodized table salt.

      • space says:

        Right and most people are not eating cheap iodized table salt any more because it’s unhealthy, they’re buying natural sea salt or grey french salt to get the mineral benefit. Make sure it’s been iodized!

      • guyatitian says:

        Hmmmm. I wish I could agree with you that sea salt was “healthier”. Truth is, we shouldn’t be looking for health benefits from salt – it should only be viewed as a necessary seasoning to make healthy foods more enjoyable. I had a customer at the health food store I once owned who I told the same thing to as you just said to me – he nearly had a stroke from his “natural” sea salt. If you have high blood pressure you need to cut down on sodium period, whether it be from the earth or sea.

  12. […] in calcium metabolization and stimulating bone cells to add calcium to bone. It is the same Iodine which is present in Sea weed, Fish (Cod, Shrimp and Tuna etc), milk, Corn, Prunes, Banana, Cheese, Cereal, Apple […]

  13. such a beautiful post, thanks for sharing.

  14. mariemck says:

    Thanks for the list of foods that contain iodine. I use sea salt, so I don’t get iodine via table salt. Good to know that things I eat often, like cod and yogurt, have quite a bit of the mineral. When I make soups or stews, I usually add 1/2 – 1 tsp of ground kelp. It has no flavor that I can detect, but it does add iodine.

  15. mariemck says:

    Thank you for this list of foods containing iodine. Since I use sea salt instead of regular table salt, this is good information to have. I often add ground kelp to soups and stews. It has no taste that I can detect and it is a source of iodine.

  16. Emilie Unkrich says:

    Thank you for this great information.
    I have posted your URL on my Facebook Page for other’s reference as well.

  17. LuCille Peveler says:

    I’m allergic to shellfish and years ago…like 25 years ago!!!..was cautioned to avoid iodine products,tests, etc. Has this precaution been overturned? I’ve been researching iodine and foods rich in this element and I have no issues with those foods–although I have avoided kelp for some reason. Any comments on this or suggestions for further clarification?

  18. […] Iodine deficiency leads to cretinism.  And iodine deficiency is one of the worlds leading causes of mental retardation.  Most western diets have enough, because our foods are enhanced. Here’s a list of easy, good sources of Iodine. […]

  19. Layne Hackworth says:

    Iodine supplements are great specially for those people who have thyroid issues. I wont prefer taking extra seafoods instead of iodine supplements. ‘**;,

    Yours trully

  20. Aidan Moran says:

    Potatoes are also a very good source of iodine. Depending on the soil quality, they can have as low as 13% DV of iodine, and all the way up to over 50% DV. One larger sized baked potato and some iodized salt will generally get you pretty close to your full day’s need of iodine.

  21. […] you can skip to the next part of this article: According to David Grotto’s Nutrition House Call (, posted on March 16, 2011),  the following consumables (+ several others) contain iodine, in the […]

  22. Way late for a reply, but the reason iodized salt isn’t used in processed food and canning (apart from any legal issues) is that the iodide ion dissociates when exposed to high heat and makes food taste awful. Good post, helpful reference.

  23. says:

    At least seven of the “natural” food sources you list are highly process, manufactured, artificially enriched food sources. I would think and article call “Natural Food Sources of Iodine” would only include sources that are truly natural, not man-made.

  24. anass nashiru says:


  25. sean says:

    yeah i also appreciate u for taking a bit of trouble out of my way

  26. […] great salt, like Celtic sea salt, and some pepper, and lots of ground seaweed. Seaweed is full of iodine, which is something that most of us are low in.  Let the whole thing simmer for 24 hours. Then […]

  27. Dorothy says:

    I have been applying iodine to my toenails in an attempt to cure toe nail fungus
    It stopped it in its tracks but when I stopped applying it the fungus began to increase any advise would be appreciated.

  28. qatheworld says:

    When I was a kid we used to put iodine on cuts to disinfect them and you could buy it at the drugstore. But it seems no longer to be available in stores, I haven’t seen it for years. Why? :/ Where are you getting it?

    • nudrnanna says:

      Have Iodine Tincture in hand… it is a first aid Antiseptic to help prevent skin infections in minor cuts, scrapes, and burns. It is only 2% iodine and has caution POISON on label… not the same iodine as that in table salt. It has been taken off the shelves, but one can purchase it if they ask for it at the counter…. please don’t drink it !!!!

  29. Chinelo nwosu says:

    I am really impress, my elder sister has thyroid problem that motivate me to seek source of iodine because i dont want to fall a victim, thanks.

  30. China Frazier says:

    can I just eat a sheet of nori each day and get enough iodine?

    • guyatitian says:

      Hi China:

      In fact, that’s what I do! I love nori seaweed which is the type commonly used in making sushi. Many companies offer it flavored and I typically eat about a gram to two grams, of the wasabi variety, per day . Its a yummy way to get your iodine in!


  31. oluwakemi thompson says:

    I want to know more about a source of iodine

    • Hi david, due to the Japanese environmental degradation I have stopped looking for food sources and just take iodoral.

      • guyatitian says:

        Hi Anita:

        I can certainly appreciate your concern. However, most of the seaweed manufacturer’s have vouched for the safety of their products. Though there has been rising arsenic levels, I haven’t seen reports that edible seaweeds, that are sold in the marketplace, contain enough arsenic or radiation to be a concern at this time. Hopefully this continues to be the case. Thanks for your thoughts!


  32. oluwakemi thompson says:

    I want to know more about (source of iodine).

  33. Katherine says:

    My understanding is that we need a source of iodide (the isomer to iodine with an extra electron). Any chemists out there that can tell me why we can’t convert iodine to iodide in the body? Can you confirm what I have heard about the need for iodide as well as iodine in a proportional balance? Iodine Plus 2 supplements for instance have 7.5 mg of iodide for every 5 mg of iodine. Does seaweed/kelp/kombu have iodide as well as iodine? I understand from Dr. Brownstein’s book that some tissue prefers iodide to iodine and we need both. Thanks in advance for the help finding natural sources

  34. ピューマ スーパースター

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