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An Update on Iodine And Thyroid Health

Published September 12 2016

Many people with thyroid and autoimmune thyroid conditions are confused with regards to iodine supplementation.  While some healthcare professionals still recommend large doses of iodine to their patients, other healthcare professionals recommend for people with thyroid conditions, and especially those with autoimmune thyroid conditions, to completely avoid iodine.  Although I consider myself to be “pro-iodine”, over the years I admittedly have become more cautious when it comes to recommending iodine supplementation to my patients.  In this blog post I will be discussing my personal experience with iodine over the years, my current perspective, the benefits and risks of iodine supplementation, and I’ll also talk about some of the different forms of iodine supplements.

My Personal Experience With Iodine Supplementation

When I followed a natural treatment approach for my Graves’ Disease condition, the healthcare professional I was working with recommended for me to supplement with higher doses of iodine.  Before doing this she did recommend for me to obtain a test for iodine…she recommended the 24-hour iodine loading test, which involves taking a 50 mg tablet which consists of iodine and potassium iodide prior to collecting the urine samples.  After a deficiency was discovered I began supplementing with a product called Prolamine Iodine, as I started by taking a 3mg tablet each day, and I gradually increased the dosage until I was taking three tablets three times per day, for a total of 27mg.  I don’t remember exactly how long I took this dosage of iodine for, but it was for at least a few months, and I eventually did a retest of the iodine loading test, and upon seeing an improvement I began weaning myself off of the iodine.

I did very well when taking the iodine, and I didn’t experience any adverse effects.  And when something works well for you, it’s natural to assume that the same approach will work for others with similar conditions, and so when I initially began helping people with thyroid and autoimmune thyroid conditions I would recommend for just about all of my patients to do a urinary test for iodine, and if they were deficient I would have them supplement with iodine.  However, I would also have them take certain precautions, which I’ll discuss later on in this article.  Of course supplementing with iodine wasn’t the only thing I did when I followed a natural treatment protocol, as I ate whole healthy foods, did things to manage my stress, took supplements to support my adrenals and gut, etc.

My Patient’s Experience With Iodine

So how have my patients fared with iodine supplementation?  Throughout the years most of my patients have tolerated iodine pretty well.  In fact, I don’t recall any of my patients having serious side effects when supplementing with iodine, although not all of them have done well with iodine supplementation, and I have received a few emails from non-patients who had a bad experience.  My perspective of iodine began to change when I started attending nutritional conferences taught by healthcare professionals who presented research about the risks of iodine triggering an autoimmune thyroid condition.  This was especially true with regards to Hashimoto’s Thyroiditis.

With that being said, since I received good results with most of my patients, and since most of my patients took iodine, not surprisingly I was resistant to stop recommending iodine testing and supplementation to my patients.  However, it was hard to argue with the research, as some studies show a higher incidence of autoimmune thyroiditis in populations that were exposed to iodine (1) [1] (2) [2] (3) [3].  However, there is also some evidence that the reason for this might be due to these populations being deficient in selenium.

The Connection Between Selenium and Thyroid Autoimmunity

But how can being deficient in selenium increase the risk of developing thyroid autoimmunity?  Well, hydrogen peroxide plays a role in the oxidation of iodide to iodine.  And it is well known that hydrogen peroxide is a source of free radicals (4) [4] (5) [5].  These free radicals cause an increase in proinflammatory cytokines, which is a factor in autoimmune conditions such as Graves’ Disease and Hashimoto’s Thyroiditis.  Selenium is important for the formation of selenoproteins.  These selenoproteins are powerful antioxidants, and they help to neutralize the effects of oxidative stress by reducing these free radicals.  So if someone has a selenium deficiency, this will result in a decrease in selenoproteins, and this in turn will cause an accumulation of hydrogen peroxide, which will produce more free radicals, and this results in a greater number of proinflammatory cytokines, etc.

As a result, anyone who supplements with iodine will also want to make sure they have healthy levels of selenium.  Taking 200 mcg of selenium per day is commonly recommended.  Other nutrients which should be taken include vitamin C, magnesium, and the B vitamins.

Would I Have Received The Same Results Without Iodine Supplementation?

Even though I received excellent results when I followed a natural treatment protocol for my Graves’ Disease condition, I do wonder if I would have received similar results without iodine supplementation.  In other words, would I have gone into remission if I didn’t supplement with iodine?  Well, iodine supplementation was only one component of the natural treatment protocol I followed.  In addition, I’ve had patients with Graves’ Disease in the past who didn’t supplement with iodine and went into remission.  But with that being said, there is no way to know if I would have received similar results had I not taken iodine.

However, over the last few years I’ve had many patients not supplement with iodine while following a natural treatment protocol.  The results have been mixed, as many people who didn’t take iodine still received great results and were able to get into remission.  Keep in mind that even when I was commonly recommending iodine I didn’t have everyone supplement with it, as it depended on the test results.  In other words, if someone didn’t test positive for a deficiency then I wouldn’t have them supplement with iodine.  Although correcting an iodine deficiency might be necessary to achieve optimal health, correcting an iodine deficiency won’t necessarily play a role in reversing the autoimmune component.

For example, if someone has a gluten sensitivity that resulted in a leaky gut, and if this was responsible for the development of the autoimmune response, then supplementing with iodine will have minimal impact on reversing the autoimmune component and restoring the person’s health.  This doesn’t mean that if someone in this situation has an iodine deficiency that this isn’t important to eventually address, but in this situation, correcting the iodine deficiency probably won’t be a factor in reversing the autoimmune component.  However, if someone has a gut infection, while this might not be related to an iodine deficiency, we need to keep in mind that iodine is an excellent antimicrobial, and it plays a role in inhibiting biofilm disruption (6) [6] (7) [6].  Iodine is also important for optimal immune system health (8) [6] (9) [7].  As a result, in this situation, having an iodine deficiency might have been a contributing factor in the development of the gut infection.

5 Reasons Why Some People Experience Problems With Iodine Supplementation

When someone supplements with iodine and doesn’t do well, there are typically five main reasons for this:

1. They don’t have an iodine deficiency.  Although many people are deficient in iodine, the truth is that not everyone has an iodine deficiency.  This is why I recommend testing before anyone supplements with iodine.

2. They are taking too large of a dose.  Some people take massive doses of iodine.  And while some people might do well on very high doses of iodine, everyone is different.  For example, one person might feel great taking 25 to 50mg of iodine, while another person feels awful when taking a much lower dose.  Of course one has to keep in mind that you can’t always go by symptoms.

3. They have low levels of antioxidants.  As I mentioned earlier, having low levels of selenoproteins can lead to an increase in oxidative stress and free radicals upon supplementing with iodine.  Taking selenium with iodine might help, but many times it’s necessary to first increase one’s antioxidant status before supplementing with iodine.

4. They experience a “detox” reaction.  I’ll actually talk about this more next when I discuss some of the benefits of supplementing with iodine.  Although it’s a bummer to have negative symptoms, if this is associated with the detoxification of halides then this probably is a good thing.

5. They react to another ingredient or contaminant.  This can be true with any supplement, as it might not be the nutrient or herb someone is reacting to, but other ingredients or fillers.  This is one of the downsides of taking kelp supplements, as while it’s great that kelp is a food source of iodine, kelp supplements are often contaminated with heavy metals, and so it’s possible that the person who has a negative effect when taking kelp isn’t reacting to the iodine, but instead is reacting to the toxic metals.  Of course if someone has a negative reaction with different forms of iodine then one can be more confident that they are reacting to the iodine, and not a different ingredient.

What are the benefits of supplementing with iodine?

Iodine has numerous health benefits.  Here are some of the more important ones:

1. Iodine is important for the production of thyroid hormone.  Because of this, most endocrinologists will recommend for people with hyperthyroidism and Graves’ Disease to avoid iodine.  And while it might make sense to avoid iodine if you are hyperthyroid in order to avoid producing more thyroid hormone, in most cases, supplementing with iodine won’t cause excessive levels of thyroid hormone.  In fact, in the past iodine was commonly recommended as a treatment for hyperthyroidism, before radioactive iodine was used.

2. Iodine helps with the detoxification of halides.  Bromide, fluoride, and chloride have chemical structures similar to iodine, and thus they compete for the same receptor sites.  As a result, being exposed to larger amounts of fluoride, bromide, or chloride can result in an iodine deficiency.  On the other hand, supplementing with iodine can displace these other halides from the receptors, which is a good thing since these other halides have toxic effects.

3. Iodine has antimicrobial properties.  Many people reading this know that iodine makes a great antiseptic.  Iodine is bactericidal, fungicidal, tuberculocidal, virucidal, and sporicidal (10) [8].  The antimicrobial action of iodine is rapid, even at low concentrations, as iodine rapidly penetrates into microorganisms and attacks key groups of proteins, nucleotides, and fatty acids, which results in cell death (10) [8].

4. Iodine plays a role in regulating estrogen metabolism.  Iodine modulates the estrogen pathway, which seems to explain why those who consume larger amounts of iodine have a reduced risk of developing breast and prostate cancer (11) [9] (12) [10].

5. Iodine can help prevent damage from radiation exposure.  Iodine supplementation can prevent the negative effects caused by radiation, as it helps to block radiation from being absorbed by the thyroid gland.

What Are Some Of The Risks Of Supplementing With Iodine?

Risk #1: Iodine can be an autoimmune trigger.  As I mentioned earlier, the research does show a relationship between iodine consumption and thyroid autoimmunity in susceptible individuals.

Risk #2: Large doses of iodine can induce hypothyroidism.  There is also evidence of iodine exposure leading to subclinical hypothyroidism (13) [11].  However, it’s important to understand that most cases of Hashimoto’s initially result in subclinical hypothyroidism.  In other words, the person will have high TSH levels, but the thyroid hormone levels will be normal.  However, exposure to high doses of iodine can also result in hypothyroidism without involving autoimmunity, and this hypothyroid state is usually temporary.

Risk #3: Large doses of iodine can induce hyperthyroidism.  Since iodine is necessary for the production of thyroid hormone, take very large doses can potentially cause hyperthyroidism.  However, as I briefly mentioned earlier, this isn’t too common.

Iodine and Thyroid Nodules…What Does The Research Show?

So what does the research show with regards to iodine and thyroid nodules?  One study showed that thyroid nodules are four times more common in women than men and their frequency increases with age and low iodine intake (14) [12] (15) [13].  Another study showed that autonomous thyroid nodules gradually disappear from the population after iodine deficiency has been properly corrected (16) [14].  However, the same study showed that too much iodine can cause the nodules to overproduce thyroid hormone and thus might cause iodine-induced hyperthyroidism (16) [14].  Another study looked at the natural course of benign thyroid nodules in a moderately iodine-deficient area, and showed that 40 months later, only one third had nodules which decreased in size, as one third of benign nodules showed continuous growth, while another one third of thyroid nodules remain unchanged (17) [15].  A recent study did show a strong association of high urinary iodine with an increased incidence of benign and malignant thyroid nodules (18) [16], and while most patients I have tested for iodine over the years haven’t had a high urinary iodine content, this is still another reason why it is a good idea to get tested before supplementing with iodine.

So based on the research I presented, would it be a good idea for people with thyroid nodules to supplement with iodine?  Well, once again, I think it’s important for anyone who is considering taking iodine as a supplement to first conduct a test for iodine.  After all, not all thyroid nodules are caused by an iodine deficiency, and so if you have one or more thyroid nodules you might want to consider doing a urinary test for iodine.

The Role of The Sodium-Iodide Symporter System

I don’t want this article to get too technical, but I did want to briefly mention the role of the sodium-iodide symporter system.  Most people are able to maintain normal thyroid hormone secretion, even when consuming very large amounts of iodine.  The sodium-iodide symporter system contributes most to this stability (19) [14].  In addition, when someone consumes excessive amounts of iodine this actually blocks the second step of thyroid hormone synthesis, which is known as the organification of iodide (19) [14].  In certain individuals the sodium-iodide symporter fails to shut down, and this causes the intracellular concentration of iodide to remain high can can result in chronic hypothyroidism (19) [14].

The Different Forms of Iodine Supplementation

Since I always get questions about different types of iodine supplements I figured it would be a good idea to discuss them here.

Lugol’s Iodine/Iodoral.  Lugol’s iodine, which is also known as Lugol’s solution, consists of iodine and potassium iodide mixed in water.  It typically comes in 2% or 5% concentrations.  The 2% solution consists of 3 mg per drop, while the 5% solution consists of 6.25 mg per drop.  Iodoral is essentially Lugol’s solution in tablet form, although other companies have similar formulations that come in a tablet.

Nascent Iodine.  Instead of using molecular iodine, Nascent iodine supposedly consists of atomic iodine, and some claim that Nascent Iodine is a purer form of iodine and is more bioavailable than the iodine in other supplements.  I wasn’t able to come across any research which confirms this, and to be honest I don’t have much experience with this type of iodine.

Kelp.  The advantage of kelp is that it is a food-based form of iodine, as it is rich in other minerals besides iodine, and some people do better with kelp when compared with other forms.  The downside is that kelp has toxic metals such as mercury and arsenic, and while some sources are cleaner than others, this still can be a concern.

Other Forms Of Iodine

Prolamine Iodine.  This consists of 3mg of molecular iodine bound to a protein.

Tri-Iodine.  Tri-Iodine is very similar to Iodoral, as it consists of molecular iodine, potassium iodide, but it also has sodium iodide.

What’s The Best Method Of Checking Iodine Status?

Urinary testing seems to be the most accurate method of measuring iodine levels.  However, there are a few different types of urinary iodine testing available.  As I mentioned earlier, when I was dealing with Graves’ Disease I used the iodine loading test, which involves taking a 50mg tablet of iodine and potassium iodide and then measuring the excretion of iodine over a 24 hour period.  I also have recommended this test to my patients in the past, and while some have questioned the validity of the test, I must admit that I find this test to be useful.

However, although my patient’s overall experience with the iodine loading test has been positive, there can be risks when taking a large dosage of iodine/potassium iodide prior to collecting the urine samples.  And so another option is to do an iodine spot test, as this doesn’t involve consuming iodine prior to collecting the urine sample.  Some labs give the option of adding bromide, and if doing the spot urine test I think it’s a good idea to add this.  And the reason for this is because while a normal spot iodine test doesn’t always rule out a deficiency, since bromide competes with iodine, if someone has high levels of bromide then this usually indicates an iodine deficiency, regardless of what the iodine levels look like.

Should Pregnant Women With Thyroid Autoimmunity Supplement With Iodine?

There is no question that iodine is important to the developing fetus.  And so while it is controversial if a pregnant woman with an autoimmune thyroid condition should take a separate iodine supplement if an iodine deficiency has been confirmed, I think it’s a huge mistake to completely avoid iodine during pregnancy.  I discussed this in greater detail in a blog post entitled “Should Pregnant Women With Hashimoto’s Thyroiditis Take Iodine? [17]

In summary, there is a lot of controversy involving iodine supplementation and thyroid health.  Although I personally had a positive experience with iodine supplementation when I was dealing with Graves’ Disease, and while many of my patients have also benefited from iodine supplementation over the years, not everyone does well with iodine.  Iodine has many benefits, as it is important for the production of thyroid hormone, it helps with the detoxification of halides, it has antimicrobial properties, it plays a role in estrogen metabolism, and it can help to prevent damage from radiation exposure.  However, there can be risks with iodine supplementation as well, as in some cases iodine can trigger thyroid autoimmunity, and it might induce hypothyroidism or hyperthyroidism in some individuals.  Making sure someone has healthy antioxidant levels will reduce the risk of iodine triggering or exacerbating the autoimmune response.  Some of the different forms of iodine supplements include Lugol’s iodine, Iodoral, Nascent iodine, kelp, Prolamine Iodine, and Tri-Iodine.  Urinary testing seems to be the most accurate method of measuring iodine levels.