Article by Sheila Dobson, BA, NC
Do You Know Your Iodine Status?
I have been recommending testing of iodine levels frequently for clients these days. Iodine is a critical nutrient for not only thyroid function but also proper immune function, brain function, the health and function of all the endocrine glands, detoxification capability and mechanisms, mood, emotional resilience, and really, the health of every bodily tissue, organ and gland.
Given that iodine is so critical we should know whether we need to supplement it and also keep tabs on how we are doing as we strive to reach a state of sufficiency. Not every nutrient requires this kind of vigilance, but in the case of Vitamin D, and iodine, I feel this is best for nearly everyone. Bear in mind that these two nutrients are deficient in almost everyone!
Difficulties in Assessing Iodine Status
The trouble with assessing iodine status is, as we shall see, not all testing options are very accurate, and furthermore, most doctors, even naturopathic and holistic doctors quite often, are afraid to recommend supplementing with more than tiny amounts of iodine. However, if all you ever use are tiny amounts, when defiency is serious, you will never get to a state of sufficiency. And that means you will lose out on the feelings of well-being and robust health that a proper iodine level can provide.
In this article I cover basic facts about testing the body for iodine sufficiency. I hope to help you understand the various options, how interpreting results is done and clarify why I believe there is really only one good option for assessing iodine status.
Iodine Levels In Different Tissues – Blood, Urine and Hair
Iodine levels can be assessed in blood or blood plasma, as well as urine and hair.
Iodine in Hair
Ideally we would choose hair mineral analysis for determination of iodine status because it is inexpensive and convenient, however this is not a realistic option. Iodine levels in hair tissue can be measured and research has demonstrated the normal values, however, the two labs we utilize for hair mineral testing do not perform an assay for iodine. The reason for this is that iodine, being such a volatile element, quickly oxidizes or combines with other elements and this makes spectroscopic analysis of iodine levels a less useful measurement than it would seem to be.
Given the above limitation, in this article we will discuss testing for iodine in urine and blood. When urine is tested, there is more than one approach. We will see why the 24 hour “loading” test in which a person takes a dose of a known quantity of iodine before collecting urine for 24 hours, is in many ways the most helpful way to test, though a “spot” or random urine test can also be useful.
Iodine Levels in Blood
Iodine levels in whole blood or blood plasma can be ordered by a physician. This test is commonly performed by commercial medical laboratories in the US such as Quest and LabCorp. In some cases you may be able to order these tests directly without visiting a physician for a requisition.
Blood Iodine Levels – What is a Normal Result?
The answer depends upon whom you ask. Typical blood iodine reference ranges used by laboratories in the US are between about 52 and 109 mcg/L. Other sources state a much higher upper level for normal blood levels, for example, a reference book of mine gives a range for blood iodine levels of up to 300 mcg/L (Dinicolantonio, 2021).
The limitations of blood testing for iodine are similar to those for any other mineral in the sense that what is found in blood may be quite different from that found in tissues in the body. For example, minerals like calcium and magnesium may show at sufficient concentrations in the blood, while tissue levels are low or high. In other words, the amount of a mineral found in the blood is often not a good reflection of bodily sufficiency for the mineral. This, in fact is one main reasons why we like to use a hair mineral analysis to assess mineral nutrition.
There is still some usefulness to doing a blood iodine test. A low level is likely to actually indicate a deficiency. However, a reading that is “normal” doesn’t necessarily mean a person has adequate body stores of the mineral.
The Problem with Laboratory Reference Ranges
The reference ranges provided by labs for this measurement are like those for many other laboratory tests today; the range reflects the degree of illness and deficiency of the modern population. This is because modern medical lab tests at least in this country are referenced to the “norm” (in other words typical levels found in a sample of about 40 “normal, healthy” people in the modern world. It is also because people are considered normal and healthy as long as they don’t qualify for a disease diagnosis. A better way to determine reference ranges would be to use levels known to produce the best health outcomes.
Iodine Measurements In Urine
Urinary iodine excretion is a standard medical lab test used to measure iodine sufficiency in a person’s diet.
Most Western medical doctors will assert that so long as enough iodine is present in a person’s diet, there is no need to be concerned about a deficiency of intake.
Limitations Of Urinary Iodine Measurements for Determining Sufficiency
A random or “spot” urinary iodine level has some value in determining your status just like a blood level does. However, this method can be problematic due to the way levels may change based on one’s recent diet and other factors. The meals a person has eaten in the last day or so, and the body’s need for iodine and ability to uptake iodine into the thyroid and into body cells, will impact how much iodine is excreted in urine. If you ate lobster and seaweed soup for dinner the day before the test, the levels might show up much higher than if you had had a burger and fries.
What shows up in urine is what the body is eliminating. If you eliminate very little iodine, it could be that you are lacking it so badly that the body holds onto it very tightly. So a low result would indicate a deficiency. However, it could also be that you just have had a very low consumption of that nutrient in the recent past but your tissues, organs and glands are not terribly lacking in the nutrient. If on the other hand you eliminate a good amount of the mineral, iodine in this case, it could be for various reasons, not just because you have plenty of that nutrient; you could have a problem absorbing it, you could have toxins sitting in the spaces where iodine should go, and the body is just not dumping those toxins, or you could actually be sufficient in that mineral.
By itself one measurement of iodine in urine is somewhat useful, but less than optimal for determining body sufficiency. And the reference ranges again are a problem.
Reference Ranges for Urinary Iodine Levels
The World Health Organization reference range for urinary iodine for children over age 6 as well as for adults (excluding pregnant and lactating women) is 100-199 mcg/L. For pregnant and lactating women, the reference range is 150-249 mcg/L. The WHO acknowledges that urinary iodine levels are not useful for assessing an individual’s status, but only for gauging such measures as the degree of sufficiency of this nutrient in a given population – in other words – are most German’s eating adequate amounts of iodine rich foods to avoid deficiency. This is because, of course, the day-to-day fluctuations will average out in a population when a survey of a population group is done.
One of the biggest labs in the US has a reference range for this test of 28 – 544 mcg/L. This gives one a sense of how wide the range can be that is considered “normal” for what a person might excrete in urine.
The Best Approach for Determining Whole Body Sufficiency For Iodine; a 24-Hour Urinary Iodine Excretion Test
Iodine is such an important mineral that we don’t want to risk being deficient in it. People who are low in iodine risk a higher chance of getting cancer, thyroid disease, and chronic fatigue and weakened mental function, among other problems; virtually any health problem from neurological disorders to recurrent miscarriages, could have a connection to deficiency of this important nutrient.
Given that blood and urine measurements are not very good ways of determining the body’s sufficiency for iodine, we have to be a little more sophisticated to get an accurate picture of a person’s iodine status.
In recent years there are a number of laboratories that have begun offering a 24-hour urinary iodine excretion test. The original laboratory to offer this test is Hakala Labs, which was created by one of the physicians involved in the original “Iodine Project” — a project of three physicians that determined how to measure and supplement iodine correctly. This is a test, which, if done properly after a test dose of two forms of iodine (such as that found in Iodoral or LugoTab), can yield a fairly useful picture of the iodine status of a person.
To do this test, a person collects urine over a 24-hour period after consuming a known quantity of iodine/iodide, usually 50 mg. Although urine for the whole 24 hours is collected, only a small sample from this collection needs to be submitted to the laboratory. Based on the total urinary volume and the concentration of iodine in the sample that is analyzed the laboratory calculates the total amount of the 50 mg dose of iodine that was excreted in the urine. The percentage of the dose that is excreted helps gauge how sufficient a person’s iodine stores are. The more deficient a body is, the more it will retain of a given dose of iodine. An arbitrary sufficiency level of 90% excretion of a standard test dose of 50 mg of iodine/iodide has been set by the developers of this test, Dr. Guy Abraham and his associates. Based on this criterion, nearly everyone in our modern society is deficient.
Of course, there are other factors besides just the body’s need for iodine that can affect how much of a given dose of iodine is absorbed versus how much is excreted. For example, even if a person’s body is very “hungry” for iodine, it may excrete the majority of the test dose simply due to an inability to uptake iodine. This is a problem known to occur in some people, and it is due to what is called the iodine symporter defect. There are other potential interfering factors also, including the problem of toxicity with other halides such as bromide and fluoride. Some labs, including Hakala labs, will check for these toxins if you wish to do so.
Often a “spot test” which is just a random urinary iodine excretion test will be ordered at the same time as the 24-hour iodine “loading” test. These two measurements together can be very helpful.
While I believe it is important to be sure that you are not vastly deficient in iodine, I do not necessarily believe you must reach a level of 90% excretion in order to obtain great benefits from iodine supplementation. Rather, I think it makes sense to get a measurement to find out where you stand, and then if you are not at a fairly high level of sufficiency, undertake the remediation of that deficiency in a slow and careful way. And of course also, if you are showing “sufficiency” based on the 90% excretion of the test dose criterion, yet are experiencing symptoms that may be related to iodine deficiency, it would be important to asses for the symporter dysfunction and possibly the presence of the toxic halides.
My Experience
In My Own Case
Within the past couple years, I have attempted to have blood iodine levels measured three times for myself; they were actually only measured twice however. A little background on me….I have a history of poor thyroid function going back decades, and in recent years was told by a naturopath that according to her guidelines I qualified for a diagnosis of Hashimoto’s hypothyroidism.
The first blood iodine measurement I obtained was when I was having some fairly severe low-thyroid symptoms. The test revealed a value of 45.9 mcg/L. The reference range for this lab was 40 – 92 mcg/L (micro international units per milliliter). At that time my TSH was 3.82. The normal range for TSH for this lab is 0.45 – 4.50. Clearly, a TSH reading of 3.82 is toward the upper end of the acceptable range. According to many naturopaths and natural health experts, anytime a person has a TSH level over about 1.5 is an indication of a need to check whether there might be a problem.
The second measurement was made when I was supplementing iodine with fairly large (by conventional standards) doses of iodine – in the range of 12 to 36 mg per day of Lugol’s solution. My blood iodine level then was 195.2 mcg/L – more than double the upper end of the reference range which was 92. At that point, my TSH was 1.06 — a much more moderate “in range” value compared to 3.82.
During this time, if I carried on supplementing the higher doses of iodine past a certain point, about 2-3 months, I would reach a sort of roadblock and need to stop supplementation. I would have some thyroid swelling at these times. Nonetheless, up to that point, I would see many improvements in my overall health that I attribute to the improvements in thyroid health and other health measures like brain function, mood and energy.
The third time I tried to get this test done, I never received results because the sample was either lost or damaged according to the lab. My TSH at that point was 0.98.
At the time I received the TSH result of 0.98, I had returned to supplementing iodine at fairly high levels during the few months prior — this time using an iodine/iodide tablet. The amounts were slightly higher than in the previous supplementation spell. I suspect that the lab did perform the iodine test and found a level so high that they concluded it “must be in error” since it was so high. This may sound like a strange assertion since mistakes happen all the time, of course. However, if you study the iodine literature, you will find that there is a phenomenon in the medical community in this country that a leader in the field of iodine nutrition, has dubbed, “iodophobia.”
Iodophobia – An Important Factor
Many doctors and professionals in the medical field would think that a person with a blood iodine level of 350 ng/L or maybe 500 ng/L was “toxic” with iodine and would surely come to harm. However this is in most cases not likely to be true. Iodine is really not a scary nutrient that is likely to result in toxicity whenever someone supplements with milligram (as opposed to microgram) amounts, except in a very few, rare cases. However, this is what medical people have been trained to think will happen to just about anyone who supplements with higher amounts. Naturally, supplementing higher amounts will result in higher readings on blood and urine tests.
Not long after that third blood iodine test, I had a 24-hour urine “loading” test done, and the results showed that I excreted 76% of the loading dose and the “spot” test (random urinary iodine level) revealed an excretion of 120 mcg/L. This (spot level) level is actually LOW by the WHO standards of 150 mcg/ml minimum.
What this shows us is that a person can have a blood iodine level that is high by conventional laboratory standards (I’m referring to the first blood iodine test that showed I had an iodine level around double the high end of the reference range), while at the same time showing a level that is low by WHO standards for urinary iodine excretion. Furthermore, around the same time, a 24-hour iodine loading test showed an excretion of 76%, indicating I was well below the 90% considered to be an indication of full body sufficiency.
My experiences also show that at least for some people, iodine supplementation resulting in improved levels can dramatically influence the TSH. TSH or thyroid stimulating hormone, is a measure of how hard the thyroid has to work to produce enough hormone. In some people the TSH will actually increase when iodine is first supplemented, and often it increases into the very high numbers, but this is temporary, and later it will go down.
My Experience With Clients and The 24-Hour Loading Test
I have access to the results of 5 people’s 24 hour iodine loading tests. Four of these people also got the “spot” test.
Two of these five individuals showed spot tests with values of 110 mcg/L (remember the low end of the WHO reference range is 150 mcg/L), and both of them excreted 50% of the loading dose of iodine. Another individual had the same spot test value of 110 mcg/L but had an excretion level of 63%.
Another person had an excretion level of 66%. This is someone who had standard blood tests indicating a diagnose-able thyroid condition.
The final person is myself, with a spot test revealing 120 mcg/L levels and a loading test showing 76% of the loading dose eliminated.
This shows me that when a person takes a few capsules of kelp daily (this is the case with four of the five individuals mentioned), they will likely show a fairly low level of iodine sufficiency (around 50% of a loading dose excreted). When relatively aggressive supplementation is underway, it will result in as much as a 10% greater excretion of the loading dose – indicating the person is that much closer to sufficiency.
The Usefulness of the Loading Test
To me, the true usefulness of the test is to get a baseline, and have a way of comparing from year to year, how a person is doing in their quest to become as iodine sufficient as possible.
My Philosophy
I don’t believe it is necessary to attempt to reach an arbitrary goal, but rather, to see the results in conjunction with other factors and use these to guide supplementation. Symptoms and important life-quality indicators such as mood and brain function are the best guide. When a level of well-being is reached, it is not necessary or advisable to push too hard with supplementation, but rather, to simply hang out at that level with steady supplementation, and keep an eye on one’s status and adjust or stop iodine supplementation appropriately when something changes.
Words Of Caution
Before attempting iodine supplementation on your own, I advise you to find a knowledgeable practitioner to guide you. This is because there are other nutrients that need to be supplemented when you use high dose iodine supplementation. Most notably these are selenium and vitamin C, but also at times vitamin B2, niacin and potentially others. Also, there ARE cases of people who have thyroid conditions which become aggravated if too high a dose of supplemental iodine is used. And there are instances where iodine is not properly taken up by the body (which can be determined by doing a loading test) and then this problem needs to be properly addressed. If you need a practitioner, Hakala Labs maintains a list of iodine-literate practitioners — see their website for more information — www.hakalalabs.com. I would be happy to assist you myself, as well.
Summary and Conclusions
When done correctly, iodine supplementation can help us attain a degree of health that would otherwise be elusive. Having adequate iodine levels can impact issues we may be fighting with other nutrients when it is really iodine that we need, for example, blood sugar problems, brain fog, depression, cancer, immune dysfunction – this list goes on.
Iodine is such a critical nutrient that there is really no substitute for adequate levels.
While the conventional medical professionals use blood testing and spot or random urine testing to gauge iodine sufficiency in the body, these methods are lacking. The reference ranges are problematic because they are based on the absence of diagnose-able disease rather than the presence of robust health and a high functioning brain and cheerful and resilient mental state.
The best test for assessing iodine status is the 24-hour urinary iodine loading test. This can provide a guide and a baseline that will help practitioner and client choose appropriate supplementation when needed. I suggest that if you are looking for this test, you go directly to Hakala Labs, though there are other labs now that offer it as well.
It is my opinion that actual sufficient levels may not be quite as high as the arbitrary 90% of the 50 mg loading dose being excreted within the 24 hour period following the dose. However, the jury is still out on this. I am open to the possibility that this is what is needed. Even while I’m uncertain about this, I believe the test is useful to get a feel for how aggressive supplementation might need to be in any person’s case. Symptoms and how a person feels are other important indicators.
REFERENCES
Dinicolantonio, J., & Siim Land. (2021). The mineral fix : how to optimize your mineral intake for energy, longevity, immunity, sleep and more. Independently Published.
Iodine Reference Articles., https://www.hakalalabs.com/Research_ep_41.html