Saturday, May 2, 2009


Iodine is an essential trace mineral. It's required for the formation of activated thyroid hormones T3 and T4. The amount of thyroid hormones in circulation, and the body's sensitivity to them, strongly influences metabolic rate. Iodine deficiency can lead to weight gain and low energy. In more severe cases, it can produce goiter, an enlargement of the thyroid gland.

Iodine deficiency is also the most common cause of preventable mental retardation worldwide. Iodine is required for the development of the nervous system, and also concentrates in a number of other tissues including the eyes, the salivary glands and the mammary glands.

There's a trend in the alternative health community to use unrefined sea salt rather than refined iodized salt. Personally, I use unrefined sea salt on principle, although I'm not convinced refined iodized salt is a problem. But the switch removes the main source of iodine in most peoples' diets, creating the potential for deficiency in some areas. Most notably, the soil in the midwestern United States is poor in iodine and deficiency was common before the introduction of iodized salt.

The natural solution? Sea vegetables. They're rich in iodine, other trace minerals, and flavor. I like to add a 2-inch strip of kombu to my beans. Kombu is a type of kelp. It adds minerals, and is commonly thought to speed the cooking and improve the digestion of beans and grains.

Dulse is a type of sea vegetable that's traditionally North American. It has a salty, savory flavor and a delicate texture. It's great in soups or by itself as a snack.

And then there's wakame, which is delicious in miso soup. Iodine is volatile so freshness matters. Store sea vegetables in a sealed container. It may be possible to overdo iodine, so it's best to eat sea vegetables regularly but in moderation like the Japanese.

Seafood such as fish and shellfish are rich in iodine, especially if fish heads are used to make soup stock. Dairy is a decent source in areas that have sufficient iodine in the soil.

Cod liver oil is another good source of iodine, or at least it was before the advent of modern refining techniques. I don't know if refined cod liver oil contains iodine. I suspect that fermented cod liver oil is still a good source of iodine because it isn't refined.


David Moss said...

Apparantly a cup of milk, yoghurt or one egg contain 87%, 58% and 23% of the RDA respectively, so hopefully most readers are pretty set anyway. That said sea vegetables blows all of the above away (276% for a quarter cup). (tried to check but couldn't find any data for it).

Tom Jeanne said...
This comment has been removed by the author.
Richard Nikoley said...

My favorite way to get a bit of extra Iodine is some Ikura sushi.

For 25 years, my favorite.

Bonus: some K2 (MK-4) to boot!

Tom Jeanne said...

Stephan, any opinion on the merit of high-dose iodine therapy as advocated by Guy Abraham and David Brownstein? The idea being that with the high amounts of bromine, fluorine, and chlorine in today's environment, many people are iodine deficient and require large amounts to correct thyroid problems. 50-100 mg a day is a typical dose.

Stephanie said...

Stephan- how do you cook beans w/ the seaweed?

Robert M. said...


For kombu, take a sheet, cut some slits into it with scissors, and drop it on the top of the water. I don't eat beans but traditional sushi rice recipes include it.

Unknown said...

RDA=Ridiculous Daily Amount

For good information and research...

ItsTheWooo said...

Does tincture of iodine raise blood level? I notice on days when I paint my abdomen with it, I seem to have more energy. But this could easily be incidental/placebo.

What about iodine induced hYPOthyroidism? The thyroid decreases its uptake of iodine to compensate for a high level in blood... this is a risk if we overdo iodine like from abnormal excessive intake of sea veggies or supplements.

I have heard iodine was banned from maternity units because of the risk it might pose to the fetus if it got in eyes/mouth (and hypothyroidism, even if temporary, can damage a neonatal nervous system permanently)

Jacqueline said...

Yes, you can absorb it that way - through the skin I mean. In fact, how fast the stain disappears is an indication of your iodine status I believe.

gunther gatherer said...


Those two doctors prescribe Iodoral at 12.5 mg iodine per tablet, and claim therapeutic effects at doses of even up to a gram daily.

Just doesn't seem very paleo to me.

I think the problem is the factors that are blocking iodine in the body, especially in the thyroid and prostate. Seems to me if we stop eating the toxins, preservatives, flouride, receptor-binders, etc. which are found in high numbers in White Man's Food in the first place, you don't need so much iodine to flush these things out.

BTW Stephen, don't eggs contain a fair amount? So any paleo diet approach containing them should cover us, no?

Unknown said...

The problem with the refined salt is same as refined sugar. Your body expects to receive more than sodium cloride, it is looking for the minerals that were there before the refining process. So your body is put out of balance with too much sodium chloride and not enough of the minerals to balance it. The result is everyone is being told to eat less salt to bring down their blood pressure when they should be told to eat real salt. Paul

Jenny Light said...

A theory as to why the Japanese can consume so much soy (a thyroid inhibitor) is because they eat seaweed daily.

In traditional households, they consume miso soup with each meal (in a fish stock base, made with the whole fish including the heads).

Asian's believe strongly in the balance of all things. A terrific thing for all of us to remember!

Malibu said...

i just wanted to let you know i have printed out like 80% of your archived blogs to read and am SO fascinated and learning so much. i just want to say thank you for putting time into getting health out there. i am amazed by the lectin and leptin response i read last night. as well all the sultures you have touched on. i will never again touch wheat, sugar or unnatural oils. thank you so much for you blog you have changed my life! btw- im only 23 so i still got a lot of learning to do!

Malibu said...

i grew up in MD and a lot of my relatives lived in West virginia. they use to have problems there with iodine and goiters(sp?) but it was supposidly linked to imbreeding? is there a link to iodine and goiters and imbreeding? kinda gross i know but i was just curious.

homertobias said...


Take a deep breath. I almost 100% agree with you. If you haven't checked out the New England Journal article on the lack of iodine in prenatal vitamins (last November I think), its interesting. That iodine is preferentially excreted in breast milk, and that postpartum depression is linked to subclinical hypothyroidism fascinates me.
Tom - as Jennylight says, all things in moderation - I suspect Guy and David are over the top. My experience with trace minerals is that they need to be in balance. If you take too much of one, you inhibit the absorbtion of another.
Itsthewoo, Jacqueline, yes, you can absorb iodine through the skin. But the absorbtion rate is highly variable depending on skin thickness,skin hydration, etc. I have read data that the "iodine depletion test" using lugols on the skin and measuring absorbtion is bogus.

David Moss said...

Holly, Lots of rda's are ridiculously low certainly. I've never come across any research suggesting benefits to huge doses of iodine before, so I was provisionally taking between the rda and tui to be reasonable (150-1100), and since even the media American gets up to 300 per day, I was asserting that most readers (presumably eating lots more proper dairy, eggs and seafood) were pretty much sorted.

As to the links to The Iodine Group and the supplement company you sent me, their research seems almost exclusively to be by the Abraham and Browstein chaps being discussed above. Since I've never hitherto come across any of their arguments though I'll abstain from picking sides in the debate!

NB I bought some iodine rich sea vegetables today, inspired by the blog nonetheless. Typically, I found out on my return that I'd managed to get hijiki- the only seaweed that the UK FSA recommends totally avoiding because of high arsenic levels in it being carcinogenic. Great!

Stephan Guyenet said...


Delicious. I'm going out for sushi tonight and I think I'll get some. Fish eggs were pretty much universally prized among cultures that had access to them.


I don't know but anything outside of a natural range of intake makes me suspicious.


I just throw it right in the cooking water- one 3-inch strip per pot.


I don't know if iodine tinctures are absorbed (but Homertobias says it's absorbed in her comment below). Excessive iodine is associated with high rates of hypothyroidism in some places but I haven't looked into it enough to have a well-formed opinion.


Eggs do seem to be a good source. As with dairy, the amount will depend on what the animals are eating. In the midwest, dairy and eggs didn't keep them from getting goiter before iodized salt because the soil is deficient.


Glad you're enjoying the blog. I've been learning a lot too! I don't know anything about goiter and inbreeding.


What, are you feeling all right?? I think all the problems that emerge during/after pregnancy are fascinating. Dental health goes down (ex, the folk claim that you lose one tooth per pregnancy), depression, brain shrinks, skin often becomes puffy, acne. People chalk it up to hormones but I think that's bogus, or at least not the fundamental cause. Pregnancy is a time when nutritional deficiencies are exacerbated because the baby is sucking up nutrients: DHA, AA (is that why the mother's brain shrinks?), vitamin K2, A, minerals, etc. That continues throughout lactation.

Healthy non-industrial cultures generally had a much wider margin to make it through periods of increased nutritional demands, such as growth, pregnancy, sickness, physical exertion, etc. In modern times, we eke by most of the time, but we don't have the physical resources to deal with stressors effectively.


Sorry about that. I don't have much experience with hijiki.

Phil said...

Stephan, thanks for this blog. I stumbled onto it almost a year ago. That was the catalyst for my wife and I to make some changes, like drastically reducing vegetable oils and eating more animal fat and offal. We've lost weight (25 lbs for me) and are healthier overall. If anyone's interested, this is how we're eating these days.

I wondered about your comment about the volatility of iodine, because miso soup and dried seaweed is part of our standard weekday breakfast. Do you think drying makes the iodine less available? Or is it just that fresh is better than stuff that's been sitting around for a while?

Aaron Blaisdell said...

Just bought a bag of Kombu. I think this will make an excellent addition to my stocks and soups.

Thanks for the 411 Stephen!

Stephan Guyenet said...


Fantastic. You guys eat like kings! Squid stew in a Le Creuset pot, that's classy. If only people would stop wasting squid on deep-fried calamari...

Iodine slowly evaporates out of dried seaweed, so the longer it sits on your shelf, the less iodine it contains.

Cheeseslave said...

I think most Americans are iodine deficient. Due to all the soy in our diet, as well as fluoride, perchlorate, etc. in the water. I think the RDA is woefully low. It was set as base amount just to prevent goiters.

Women who have given birth and breastfed have the highest risk of deficiency. Iodine is stored in the thyroid first then the breasts then the ovaries. I think this has a lot to do with the high rate of breast cancer and ovarian cancer in this country. As well as the very high rate of thyroid disorders.

Interestingly, in the traditional Japanese diet, they consume about 13 mg of iodine per day -- and they have one of the lowest rates of breast cancer. It would be very hard to eat enough seaweed to get that much iodine. Traditionally the Japanese eat miso soup (with bonito broth -- with the heads of fish) at every meal. The iodine is in the heads of the fish (where the thyroid gland is).

Also it is traditional in Asian cultures for the grandmothers to make fish head stock for their daughters when they have babies.

I started on 50 mg of Iodoral after my daughter was born. After one year, I am dropping down to a maintenance dose of 13 mg per day and will continue with that indefinitely to prevent breast cancer, to help support my thyroid, and also to help kick out the heavy metals I am exposed to.

Bill Cutting said...


How would someone consuming Meat and Water get Iodine? Taubes said the only mineral or vitamin in question on an all meat diet was C.

Cheeseslave said...

If you're only eating meat, you could just eat the thyroid gland of the animal to get iodine. Traditional cultures ate the glands and organs first.

Bill Cutting said...

I would think if your eating just animal meat, that animal would have had to eat food with Iodine or else you would develop low thyroid function or Goiter.

MangoManDan said...

Stephan, have you found any reputable analysis of the amount of various minerals in unrefined sea salt?

Have you found a particular sea salt that you feel is especially rich in iodine or other minerals?


Stephan Guyenet said...


I wouldn't necessarily credit the low rate of breast cancer in Japan to their iodine intake. The omega-6/3 balance seems to be critically important in breast cancer, and that's something they're doing right as well.


If all you're eating is muscle tissue, yeah you would end up with some deficiencies in the long run. Although Steffanson managed to survive that way for a year under the supervision of the AMA. But of course hunter-gatherers that had meat-heavy diets ate the organs, which is how they got most of their micronutrients.


Sea salt is not a good source of iodine, unless it has been iodized. The problem is the iodine is volatile and evaporates before it reaches your kitchen. I don't have any resources on hand for the mineral content of salt but I think you can find them online.

Phil said...

Thanks for the compliment, Stephan. We're different from royalty in at least one respect -- a policy of eating the whole animal, and the whole plant where it makes sense, is cheaper than the standard Western practice, as well as better. The fifth quarter in particular is ridiculously cheap because people are squeamish and afraid of dietary cholesterol.

I confess that I didn't believe you literally meant "volatile." I wasn't expecting much in the way of vapor pressure from iodine compounds, but I see now that some have quite respectable ones. My dried nori is tightly bagged, which helps. Maybe I should throw it in the fridge for good measure.

Can anyone tell me where to get fresh nori? We're in southern Maryland.

Stephan Guyenet said...


Yes, elemental iodine is quite volatile. I don't know where to get nori in your area but dulse is traditional in the northeast.

Anna said...

What's sad is how hard it is to source things like fish heads, etc. to make broth. I live within 5 miles of the Pacific coast and it looks like I might have to take up fishing to get what I want. I've tried several stores along the local section of the coastal cities, renowned for their seafood counters, but most of the seafood is flown in and much is already cleaned (similar to the primal cuts for land mammal meat). Believe it or not, they discard the egg casings, too. Said there was no demand for it.

Some phoning around in SD (the fishing/seafood area is about 30 miles drive away, plus traffic considerations ) indicated hit-or-miss possibilities for "fish offal". It's really a shame that such valuable resources are usually discarded due to such low demand. Probably the collection of scarps for pet food manufacturing is worth more than keeping it fresh for the very few customers that express interest.

Cheeseslave said...

Anna - I see wild-caught whole Thai snapper regularly at Whole Foods here in LA. They have the heads on. Just throw the whole fish in to make stock.

I've also used whole lobster bodies (heads intact, sans tails) to make stock.

Anna said...

Thanks, Cheeseslave, very good to know. I don't get over to WF very often, because it's at least 2-3X farther drive than somewhat similar locally owned stores and beyond a major traffic pitfall that I try to avoid (plus with a CSA box and bulk meat buys from ranches, I don't make as many food shopping trips anymore). But perhaps I could combine some errands and pack a cooler with ice.

I heard just this week from a woman I met in a local boutique/studio ( who is also really into real food) that there's a new WF coming to my town, perhaps next year, as part of a controversial coastal redevelopment project, with shops at street level & residential units above, so that will be convenient when the need arises (and right around the corner from a favorite local coffee house). I'll still try to spend my bucks first with the locally owned businesses, though.

Stephan Guyenet said...


Yeah I'm really lucky here. I can buy whole salmon heads from the fish vendor. They're huge and they have about 1/2 lb of meat on them. They barely fit in my soup pot. I think I pay $2 a piece.

Anna said...

Ooohhh, I get so jealous of you folks in the PNW and Northern Cal sometimes (other places, too). People go on and on about our mild SD weather and beaches, etc. and ask why anyone would move away, but I can think of a number of reasons, food sourcing being a major one. I've enjoyed living in different regions in the US (NE, SE, and now coastal SW, but the grass IS greener in other places in some ways, literally and figuratively. Though SD is a good place to "be stuck" :-).

However, things are looking up, food-wise. Just stopped in to take a peek at a new local restaurant's menu today, The fish is line caught and harpooned by local fishermen (not sure if that means the fish are local though, or if the local fishermen travel afar). And I learned their beef is raised on grass within the county, sourced through this place: We don't eat out very often, but this one looks like a place worth considering.

And I've got to pay that butcher a visit. It's in La Jolla, so it'll be pricey, but I'm not after premium steaks like everyone else, I want the freaky bits, so they'll be cheaper (I hope.

Iodine has been on my mind lately, thanks to your post & Dr. Davis's. So I have been playing around with some very nice wildcrafted Mendocino dried sea vegetables (, a gift from a wonderful friend last year for my birthday. If the iodine can evaporate, I guess I need to use it up! Tonight I made a huge "terre-mar" salad of land and sea vegetables, with yellowfin ahi sashimi. I just didn't buy enough tuna - my son liked it more than I realized and nearly ate half of it before we put on the breaks (he didn't go for the seaweed vegetables though (he did try them). Guess I need to find some sashimi that is lower on the food chain though.

Anna said...

My Mendocino friend sent me these links:

Keep in mind dried seaweed is very light. Easy to store and order online (shipping charges should be fairly low) if local stores don't stock it. The packages can seem expensive, but there's no water to pay for and a little can go a long way if you toss it with a regular green salad or garnish with it. When plumped up in a water soak for 15 minutes, dried seaweed can double or triple in bulk. I cut the longer strands with kitchen shears. Some of it is good to eat dried, like a crunchy snack. The dried sea palm fronds I have are slightly salty and are great broken up and mixed with nuts for a custom trail mix.

cees said...

I'd be careful with seasalt. I've read that it can have some adverse effects, as per the studies of Dr. Hal Huggins. I know personally, I've been using it for 15 years and have been having health issues. I have always been allergic to shell fish, thus there maybe a correlation with that.

I don't know if I can explain it good enough, but Dr. Huggins is saying that the unbound Minerals in Sea Salt are not in the form to assist your body and can damage your chemistry. He recommends the use of Morton's Canning and Pickling Salt. It is in a pure state without Aluminum additives used for the free flow of the product.

I think it's worth checking out especially if someone is having thyroid issues.

Ed said...

I e-mailed Green Pastures to ask if their fermented cod liver oil had been tested for iodine content (knowing that it is likely to vary by batch, but one data point might still be interesting.) Dave Wetzel replied with "Tested one time 22ppm." Hrmmm. I wonder how you would convert that to micrograms per milliliter. Any chemists out there feel like taking on the challenge?

Stephan Guyenet said...

Hi Ed,

Assuming the "parts per million" is referring to parts per million triglyceride molecules (the oil should be mostly triglycerides), and assuming an average triglyceride molecular mass of 476 Da (may actually be higher), it comes out to about 12 micrograms of iodine per serving. That's about 1% of the US recommended daily allowance.

I don't know if my assumptions are correct. If there are a lot of smaller molecules in the mixture, it would mean the concentration of iodine is higher. It's hard to say for sure without knowing the measurement in grams per liter. That would have been a much more useful number.

Stephan Guyenet said...

I also assumed a serving size of one teaspoon.

Ed said...

Without checking your other math, 12 micrograms is 8% of US RDA for adults.

US RDA for iodine table at the Linus Pauling Institute

And 1 teaspoon of high-vitamin fermented cod liver oil is quite a bit of vitamin A. So I suppose one would not want to depend upon their FCLO to provide sufficient iodine.

Stephan Guyenet said...

Ha, you're right. I actually went to the same site but I was looking at the tolerable upper limit rather than the RDA.

8% is a meaningful contribution to iodine status. So I guess CLO really is a good source of iodine.

Lynnlake said...

Stephan, I am amazed at what you have done with your blog - and thankful! But with respect to iodine, I would urge you to look further, especially to the work of Dr. Brownstein in Michigan and Dr. Flechas in North Carolina. The RDA for iodine is wholly inadequate. Many tissues in the body use iodine, not just the thyroid. There is a mainstream fear of iodine, evidenced in one vein by the many who believe it causes goiters. In fact, it reduces them and helps with countless other issues. Refined salt is bad for us and the iodine added to it is negligible. Trying to meet iodine requirements from seafood is a challenge, too, and poses the added risk of exposure to PCB and other contaminants. If you would like additional resources, I would be happy to share what I have. Again, thank you so much for all of the information you have provided in your blog!

Lynnlake said...

Another note about eliminating the need for high-dose iodine supplementation by cutting out the junk in our diets: it's only part of the picture. We are exposed to problematic chemicals, especially bromine, in the environment, as well as our diet.

As for the Japanese, I have read that they don't eat as much soy as we've been led to believe and that what they do eat is fermented (like miso).

Sorry, I read the comments after I posted! I wonder if we ever really will "get it" all. It seems every time I try to do something good for me, it turns out to be bad. But, lately I've been thinking along the very same lines as all of you in terms of what is good. It's encouraging.

mtflight said...

Hashimoto's thyroiditis, the most common presentation of hypothyroidism in the US, is an autoimmune condition. Purportedly iodine supplementation can send this attack into overdrive. I thought I'd throw this in, in case Hashimoto's patients were considering supplementing iodine.

vizeet srivastava said...

I would add my comment to it because I am recently diagnosed with Hashimoto. Most of the hypothyroid patients today have Hashimoto's thyroiditis.
This is not caused by iodine deficiency but because high amount of Iodine. Iodine causes hydrogen peroxide to get formed in thyroid gland which causes Glutathione peroxide to get formed. Selenium protects thyroid gland from Glutathione peroxide. Which is possibly the cause of autoimmunity. Our body created TPOab against it. Vitamin D deficiency increases the problem.

People who lack iodine mostly also lack selenium. People are also not getting enough Vitamin D.

I think iodized salt has created more problems than it solved. It is better to take sea salt and take sea food along with it instead of supplementing iodine.

Diana Rose said...

Great ideas flow from your mind.Aside from iodine, I take bovine for my thyroid hormones, too.

jewiuqas said...

I have just bought some dried kombu in an organic grocery. Could anyone provide me with some guidelines as to the dosage with view to get enough, but not too much iodine? Is iodine to be consumed daily like vitamin-C, for example, or is it more like liposoluble stuff, like vitamin-A and the rest, that your body can accumulate, so that you can function alright by consuming higher doses sporadically? Cooking them with your beans is a good method as far as you are making a bean soup. If you discard the cooking water, however, you discard most of the iodine as well, I reckon. A convenient solution would be to put some kombu in my tea, as I am drinking it every day anyway. I am afraid though that it would result in a somewhat fishy flavored concoction. Anyway, I’ll give it a try, some green teas or tisanes might be compatible with seaweed. But again, how much kombu to put in a cup of tea to cover my daily requirement in iodine? The sachet contains 50 grams of dried kombu. In how many days am I supposed to use it up? Does it release all the iodine if I let it steep for ten minutes in hot water (like tea), or it needs longer cooking? In fact, as I have no sign of severe deficiency, my main concern is not to overdose, but on the other hand I wouldn’t like to fiddle around for no substantial benefit. I would be thankful for any useful information.

Grey said...

"I don't know if iodine tinctures are absorbed (but Homertobias says it's absorbed in her comment below)."

I tried this as an experiment and it had a dramatic effect on my sleeping patterns (in a good way) so I've been doing it since - just dabbing some on my forearm every 2-3 days.

The first few times the yellow had all gone within a few hours whereas now it's there for most of the day.

It's only been a few weeks so who knows long term but I thought I'd throw that in.