Iodine

A place to get your questions answered from McDougall staff dietitian, Jeff Novick, MS, RDN.

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Postby dagnabit » Sun Feb 17, 2008 12:47 am

Caroll, good question ... worth bumping up to the top so we can hopefully get some more discussion.

In areas where there is little iodine in the diet—typically remote inland areas where no sea foods are eaten—iodine deficiency can give rise to goiter and cretinism, which results in developmental delays and other health problems. Iodine deficiency is the leading cause of mental retardation, producing typical reductions in IQ of 10 to 15 IQ points. It has been speculated that deficiency of iodine and other micronutrients may be a possible factor in observed differences in IQ between ethnic groups.

Because iodine is hard to come by for populations not consuming sea foods (including seaweed, which is an excellent source), many countries have mandated or encouraged its supplementation in common table salt. That is why much of the salt we purchase in the supermarket is labeled "iodized salt".

Iodine deficiency is a real problem affecting an estimated 2 billion people world-wide and it is not just confined to 3rd world countries where iodine might not yet be added to salt. What concerns me as far as a vegan diet is concerned, is that many of us are health conscious and are trying to limit our intake of salt. Unlike meat which is often heavily doused in salt to make it palatable, veggies tend to be very low in sodium and high in potassium. I have a bit of a problem with low blood pressure (hypotension). This diet tends to make it even lower. So I make sure I don't forget the salt, especially during summer months.

We tend to stress that a plant-based diet is sufficient, and no supplementation is needed except for vitamin B12. Should we also be supplementing iodine? I know I don't eat a lot of seaweed. I probably get sufficient iodine from salt, but I'm sure many of us do not.

Any thoughts on this Jeff?

http://www.sciencedaily.com/releases/2008/02/080204090923.htm
http://www.iccidd.org/pages/iodine-deficiency/faqs.php
http://www.vrp.com/articles.aspx?page=LIST&ProdID=1781&qid=&zTYPE=2
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Postby JeffN » Sun Feb 17, 2008 12:55 pm

Hi Carol

There were some studies, including the Oxford study, that did find some indications of abnormal thyroid function in European vegans who did not supplement. However, the same studies found that iodine deficiency is not as much of a problem for U.S. vegans as it is for European vegans whose food supply has less iodine in it.

Iodine is found in plant foods but it is dependant on the iodine content of the soil the food is grown on with food that is grown near the ocean tending to be higher in iodine.

There are components in soy that counteract iodine. Therefore, avoiding large amounts of soy, as I recommended in another post this week, would also apply here.

Some people choose to add seaweed to their diet for the iodine content and it is possible to get adequate iodine from the seaweed. However, you are right, the amount and the availability of iodine from seaweed is variable and if overdone, it can also provide too much iodine.

If someone is avoiding packaged products they are avoiding one of the main sources of salt in the American diet. However, if they eat out at restaurants, the odds are there is salt added to the food and often much more than people think and/or restaurants say.

Unlike iodized salt, which has iodine added to it, sea salt is not a good source of iodine as it generally lacks high concentrations of iodine.

In the US, iodized salt has about 76 mcg per 1/4 teaspoon of salt added to it which the package will state whether it has been iodized or not. This amount of salt also provides around 550 mg of sodium. Therefore, one can easily add 1/2 teaspoon of salt per day to their food and get the recommended amount of iodine and not exceed the recommended limits of sodium from the Institute of Medicine. But make sure this "added" 1/2 tsp is not in addition to a diet that is already high in sodium from packaged products and restaurant foods

Since you are already adding a "pinch" of salt to your diet, if this pinch is about a 1/2 tsp per day, this may be your best option. You will cover the iodine issue and not exceed the sodium recommendations.

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Postby JeffN » Sun Feb 17, 2008 3:23 pm

Hi Dagnabit and Carol

dagnabit wrote: We tend to stress that a plant-based diet is sufficient, and no supplementation is needed except for vitamin B12. Should we also be supplementing iodine? I know I don't eat a lot of seaweed. I probably get sufficient iodine from salt, but I'm sure many of us do not.

Any thoughts on this Jeff?


My other thought, besides the above is this is not much different than the selenium issue. It may not be a true dietary issue as much (though it has become one), but a soil, erosion and agriculture issue. Selenium deficient soils produce foods lower in selenium. Iodine deficient soil produces foods lower in iodine.

Carroll wrote: and then getting the healthier natural sea salt option (with all the minerals and none of the anticaking agents and other gunk)?


Sea salt is not really any healthier. Most of the minerals in sea salt are in very small amounts. So, if you were to try and take in enough sea salt so that you would get in enough of these minerals, you would also be taking in an extremely high level of sodium from the sea salt at the same time. Sea salt is a very poor delivery system of those few minerals. In addition, I would be much more concerned with the sodium in the regular salt than any of the anti-caking agents or other "gunk" you speak of.

Carroll wrote: I'm quite in a panic about it having only fairly recently discovered this was an issue and considering both my husband and I developed thyroid issues (in our early 30s), while it is too late for him (he had a thyroidectomy), I realize I really need to address this issue for our children... and it is troubling for me to think that possibly I didn't need to be on medication (in the form of levothyroxine), but rather just needed more iodine (I do not have an autoimmune form of hypothyroidism). I don't want my children to end up in the same situation, if it is something that is easily within my control. I think this is a tough issue because I read so much to be cautionary about overdoing iodine, but I don't know if that is just again based on the assumption that most people are eating a lot of processed packaged foods and heavily salting everything with iodized salt.


General health guidelines are based on the assumption that most people are consuming a typical American diet and typical American intakes.

My above comments were more general comments about iodine intake and vegans for general health and would also apply to your children, and are easy to control. These forums are generally not the best medium to discuss specific personal medical/health issues.

However, if we are discussing a specific medical issue and someone needed to ensure iodine intake and there is currently no way to ensure its adequacy in their food sources, and they choose not to consume any of the known food sources of it, then yes, adding iodine may be necessary. And yes, these can often be tough issues and decisions on how best to proceed.

Also, to me, there would be little philosophical or health difference between whether it is done through a food that has been fortified with it (iodized salt) or directly as a supplement (potassium iodide), as in the end you are accomplishing the same result. Just a slightly different delivery system.

Some people beleive they do not ingest any supplements and are against them but they then choose to eat food that is highly fortified and enriched, which is basically refined food that has had the exact same chemicals that they think they are avoiding in supplements just added to the food they eat by the manufacturers. In the end, it is the same thing. Some people will not take a medical drug, but will take a supplement with the exact same drug in it, thinking somehow it is safer and or better as a supplement. Yet it is the exact same chemical. Plus the pharmaceutical industry is regulated and the supplement industry is poorly regulated at best, if at all.

Sometimes, you have to do what you have to do. And shouldn't feel bad about having to make a tough choice if and when faced with one.

A health philosophy should not interfere with ones ability to achieve optimal health.

I hope this helps

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Postby JeffN » Sun Feb 17, 2008 4:38 pm

Carroll,

Carroll wrote: Right, I'm not really counting on sea salt for any health benefits, I just feel it is a better choice than a heavily refined processed version... and we try to avoid it altogether for the most part (especially since we already get sodium in the form of miso, tamari, etc.)


While I understand your point about trying to personally avoid iodized salt,; sodium chloride, without or without iodine is still sodium chloride and still a health concern. 1 TB of Braggs or 1 TB or even low sodium Tamari is still around 700 mgs per TB which in and of itself, is around 50% of the recommended intake and about 1/3 of the upper limit set by the IOM.

To me, the known adverse health effects of excess sodium is much more of an issue to vegans that I personally worry about than the potential iodine issue. However, 1/2 tsp of salt, solves one without aggravating the other. Since the problems associated with the intake of sodium chloride remains equal regardless if one was to use Braggs, Tamari, Soy Sauce, Sea Salt or Iodized salt: and one of them could easily solve the iodine issue, then to me, the choice seems simple. Pick the one that solves the issue.

If someone was to totally avoid all sources of sodium chloride, than that is a separate issue.

Carroll wrote: I guess I'm just trying to figure out if this IS a concern and it sounds like to me it is, understanding that it is ultimately a soil deficiency... I guess I'm just looking for how to best go about getting that iodine. Is it necessary to include some form of sea vegetable in most vegan diets... and if so, which one is the best choice to avoid overdoing it while still getting enough? and is it necessary on a daily basis? Or, rather, is a 1/2 teaspoon of iodized salt a day necessary, and if someone chose to iodize the salt themselves, how would you go about that? And if you did go that route, including all that salt, would you then have to avoid sodium in all other areas (i.e. no more miso soup or popcorn sprayed with bragg's, etc.)?


I do not know of it to be an issue here in the USA for most vegans or vegetarians and maybe that has to do with their intake of processed foods and/or table salt, and/or restaurant foods.

In my own personal and professional experience, I have not seen this as a problem in anyone in over 20 years of working with vegetarians and vegans. In addition, I recently wrote an article on the health and longevity of vegans and reviewed most of the data available and did not see this as an issue in the studies.

However, for general health, if it was a concern, or if someone just wanted to avoid ever having to deal with the issue, there are some simple solutions that someone could choose from depending on their own personal philosophies and/or preferences. But remember, if they are consuming processed foods, even vegan healthy lower sodium ones, and/or eating out in restaurants (even healthy vegan restaurants), it is probably not an issue due to the amount of salt still used in these situations. And, if they were avoiding both of those situations 100%, simply including 1/2 tsp of iodized salt, or consuming some sea vegetables, would address the issue.

If it was a known medical issue, this is a separate situation and then a choice would have to be made.

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Postby dagnabit » Mon Feb 18, 2008 1:07 am

AnnaS,

It would be nice to have some kind of home test that could give us some indication whether or not we are deficient in iodine or B12. Otherwise it is kind of a crapshoot. We just cross our fingers and hope for the best.
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Postby JeffN » Mon Feb 18, 2008 9:15 am

dagnabit wrote:It would be nice to have some kind of home test that could give us some indication whether or not we are deficient in iodine or B12. Otherwise it is kind of a crapshoot. We just cross our fingers and hope for the best.


First, in regard to B12, if you are a 100% vegan and consume no foods fortified with B12 and no supplements with B12 in them, and have been doing this for at least 2 years, you should be taking a B12 supplement. If you do not want to wait the 2 years you can start at any time as there is no harm from a B12 supplement. The human liver can store enough B12 to last around 3-5 years in the average person, but you do not want to push it to the end of your reserves,

Second, you can also have a urinary MMA test done which can diagnose B12 deficiency. Because it involves only the collection of urine, this test can be done at home and then sent off to a few labs who will analyze the results for you. Many walk in clinics can also do this for you (call ahead and check) and/or the blood tests also. The MMA may be the more accurate then the blood tests.

In regard to Iodine, while there are no home tests for iodine deficiency available as of now, there are simple blood tests to check thryoid levels that can be done to identify the situation. My guess is there are no home tests due to the lack of demand for them in the USA.

This is also a simple and common test (though blood has to be drawn) and they test for T3, T4 and TSH (which is the main one needed for proper diagnosis).

But remember, you would need to be a 100% vegan and consume no table salt, not eat out at restaurants regularly (where salt is added) and/or consume no packaged processed foods (that have salt added) and no other supplements that may contain iodine.

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Postby JeffN » Mon Feb 18, 2008 12:34 pm

Carroll wrote:I guess what I'm really asking is, is there a way to get the same effect as iodized salt, without the salt?


Sure.

Iodized salt is salt with iodine added to it.

You can buy the iodine, which is readily available, and take it directly without adding it to the salt.

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Re: Iodine

Postby Jeff55 » Wed Aug 19, 2020 8:19 am

Hi Jeff,
This was very helpful. I follow your guidelines and also don't add salt to my diet. How much seaweed would I need to eat to get adequate iodine? I'm not clear how much iodine is naturally in my food and how much is in seaweed. Thanks!
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