Fatigue, minor weight gain, depression, and brain fog may all be early warning signs of iodine deficiency.
Iodine is an important trace mineral that is required for thyroid function in your body.
Deficiency, due to a variety of reasons, is more common due primarily to soil depletion and the standard American diet (1).
Learn more about iodine deficiency including other symptoms of this condition, what to do about it, how to know if you should supplement with iodine, and more in this post.
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Iodine Basics & Thyroid Function
So what is iodine?
It turns out that iodine is a critical micronutrient required for proper thyroid function and for the function of other cells in the body.
Each T4 contains 4 iodine moieties, which means you need 4 iodides to make thyroid hormone (2).
Lack of iodine results in serious consequences such as thyroid disease or low thyroid hormone production.
We’ll talk more about how iodine deficiency manifests, but for now, let’s stick to the basics of iodine.
Your body can hold up to around 15-20 milligrams of iodine total.
Of this amount, around 70% is stored in your thyroid gland.
Each day your body uses about 150mcg (NOT milligrams) of iodine per day (3).
Of this 150mcg, around 120mcg or so is used up by the thyroid gland to produce thyroid hormone.
This leaves around 30mcg of iodine which is used up by breast tissue and skin tissue (important for later as we discuss the symptoms of deficiency).
What’s important to realize here is that other cells in your body need iodine as well, not just your thyroid.
Your body has a built-in mechanism, or storage capacity, to help buffer against deficiency.
15-20 milligrams (abbreviated mg) may not seem like much until you realize that 1,000 micrograms are equal to 1 milligram.
So your body stores around 15,000 to 20,000 micrograms of iodine in cases when you may be deficient.
This means that you can tolerate a few days to weeks of sub-optimal iodine intake without suffering the side effects of iodine deficiency.
But what if you don’t consume iodine in that time frame?
There is a real risk of developing iodine deficiency simply because the primary source of iodine in humans is found in the diet (4).
And the concentration of iodine in foods depends upon the concentration of iodine in the soil.
So what foods are high in iodine?
Iodine is found in significant concentrations predominately in sea vegetables (kelp, seaweed, etc.).
But when was the last time you ate seaweed or kelp?
Probably not recently.
And this is why iodine has been added to salt and other foods in the United States.
This was done because it is recognized that many people probably do not consume adequate iodine from natural food sources.
But even though foods (such as salt) are iodinated, doesn’t mean that you can’t develop iodine deficiency.
It’s now more common to use specialty salts such as Himalayan pink salt or Celtic sea salt which do not necessarily contain iodine.
This, combined with soil depletion, may explain why so many people may develop iodine deficiency even while living in the United States.
Symptoms and Warnings Signs of Iodine Deficiency
As I mentioned previously, we know that much of the iodine that your body needs is used by the thyroid.
It makes sense, then, that the symptoms associated with iodine deficiency have to do with thyroid dysfunction!
Indeed, hypothyroid symptoms tend to be the most prominent symptoms seen in patients who are iodine deficient.
At least 30mcg per day of iodine is utilized by other tissues in the body as well.
Tissues such as breast tissue and skin tissue need adequate iodine intake.
A reduction in iodine in these tissues may present with cyst formation.
In breast tissue, this manifests as fibrocystic breast disease and in skin tissue, this may present as cystic acne.
So, when it comes to iodine deficiency, it’s important to realize that this nutrient will affect more than just your thyroid.
Below I’ve included a list of the most common symptoms and warnings signs associated with iodine deficiency:
- Goiter formation – Goiter is a term used to describe a general enlargement of the thyroid gland. Iodine deficiency is known to cause goiter formation but the exact mechanism is not well understood. Goiter is often found accidentally by physical exam at a Doctor’s office visit but it can also be visualized with ultrasound testing.
- Hypothyroid symptoms – Hypothyroidism is a condition caused by a reduction in thyroid hormone production. Because many cells in your body have thyroid receptors, low thyroid hormone causes many wide-ranging symptoms. The following symptoms may be associated with iodine deficiency (caused by hypothyroidism from decreased iodine): fatigue, weight gain, hair loss, muscle pain, cold intolerance, low body temperature, infertility, high cholesterol, menstrual irregularities, and so on. You can read more about the symptoms of hypothyroidism here.
- Developmental issues in young children/kids – Iodine is required for brain development, especially in younger populations. Inadequate iodine intake, especially during pregnancy, has been associated with lower IQ in some populations. For this reason, it is very important that pregnant women and lactating women get adequate iodine intake (5).
- Pregnancy-related problems – Iodine deficiency has been known to be associated with miscarriage, preterm delivery, and congenital abnormalities (6). Because of this connection, it has been recommended that women who are looking to conceive supplement with at least 150mcg of iodine daily. These abnormalities can be completely prevented with adequate iodine intake, but supplementation may be required.
- Fibrocystic breast disease& Breast cancer – Iodine has been proposed to act as a protective agent against breast cancer and the development of cysts. Iodine replacement has been shown to treat fibrocystic breast disease in several studies (7).
- Cystic Acne – Supplementation with iodine can cause the eruption of papules which is thought to be secondary to the elimination of halides in the body. On the flip side, iodine deficiency may also be causing acne in some individuals (especially cystic acne) (8). Treatment with iodine is sufficient to eliminate acne.
Risk Factors for Developing Iodine Deficiency
Are some people at more risk than others for developing iodine deficiency?
The answer is yes.
There are several conditions that can increase the demand for iodine in your body and some conditions which can increase the amount of thyroid hormone your body is producing.
If you put increased demand on the body but don’t increase the amount of iodine that you are consuming, then you may risk becoming deficient.
The same concept holds true for those who are producing more thyroid hormones.
If your body requires more thyroid hormone production then more iodine will be required because iodine is an integral component of the thyroid hormone compound.
Other conditions may block the uptake of iodine into the thyroid gland which can cause iodine deficiency even though iodine consumption is sufficient.
So the question is:
What states cause the body to require more iodine?
Pregnancy and breastfeeding are probably the most common.
Pregnant women require higher doses of iodine because during early pregnancy the developing fetus is reliant upon the mother for thyroid hormone.
That means, during early pregnancy, the mother must make enough thyroid hormone for both the baby and the mother – increasing the demand for thyroid hormone production in the mother.
For this reason, it is recommended that pregnant women take almost double the normal daily recommended amount.
The same idea is true of lactating women or women who are breastfeeding their children.
The demand during lactation is not quite as profound as during pregnancy, but women who are breastfeeding should still take more iodine than normal adults.
Other conditions which increase your risk of developing iodine deficiency include conditions that block the uptake of iodine by the thyroid gland.
Conditions such as smoking (tobacco use), exposure to environmental factors (especially halides) (9) and consumption of goitrogenic foods/chemicals can all have this effect.
In these conditions, it’s possible to be consuming adequate iodine in your diet, and yet still have “iodine deficiency” because the iodine that you are consuming is not being used by the body.
This condition may be responsible, at least in part, for the prevalence of iodine deficiency symptoms even in areas that are said to be iodine-replete (10).
How & When to Supplement with Iodine
If you have the symptoms of iodine deficiency does that mean that you should supplement with iodine?
The answer is not as clear as you might think.
It was previously thought that we could easily erase iodine deficiency by simply increasing the intake of iodine in the general population.
This was accomplished by iodinating certain foods (such as salt) to help increase iodine intake.
Some studies have suggested a link between increasing iodine intake and the development of the autoimmune disease Hashimoto’s thyroiditis (11).
At first glance, it seems that we are in somewhat of a difficult situation.
Low iodine increases the risk of developing conditions such as goiter and hypothyroidism and high iodine intake has been shown to increase the risk of developing Hashimoto’s.
This probably isn’t the entire story, however.
It turns out that other studies have shown that adequate iodine intake is probably safe if it is also accompanied by adequate zinc and selenium.
It is perhaps more likely that our reductionist approach to nutrient supplementation is the main problem here.
What do I mean?
We have to consider that even though our bodies need certain nutrients, we almost never find those nutrients in high concentrations alone.
More often, as is true in foods, nutrients always come in combination with OTHER nutrients.
When you eat an apple you get fiber, vitamin C, phytochemicals, anti-oxidants, and so on.
With this logic in mind, it may be that over supplementing with iodine is only dangerous if it is also accompanied by deficiencies in zinc and/or selenium which may exacerbate the problem.
And studies seem to confirm that this may be the case, at least in some individuals (12).
So how should you approach supplementation?
It’s probably safest to supplement with low doses of iodine in the following ways:
- Supplement with iodine only if you are deficient
- Use iodine in small doses and in combination with Zinc & Selenium
- Find natural food sources of Iodine
- Use doses of 100-200mcg per day for most adults or 200-300mcg per day if breastfeeding/lactating
I recommend using a supplement such as this which combines zinc, selenium, and iodine together.
Is Supplementing with Iodine Dangerous?
In most cases, using small doses of iodine is probably not dangerous as long as it is accompanied by nutrients such as zinc and selenium.
It is certainly the case that many people, even those within the United States, may be slightly iodine deficient without realizing it.
Remember that the primary way that humans get iodine is through diet.
And dietary levels are largely dependent upon soil concentration of iodine.
Soil depletion of iodine and a lack of consumption of sea vegetables may increase your risk of experiencing sub-optimal iodine levels in the body.
So in many cases, supplementing with iodine is actually helpful.
But that doesn’t mean that it is without side effects.
Some individuals may experience side effects when using iodine and for this reason, it’s safer to start low with supplementation and closely monitor your body.
What kind of symptoms might you experience when supplementing with iodine?
- Gastrointestinal effects (Diarrhea)
These side effects are not common, but if present they may indicate that you are taking too much iodine.
Iodine plays a critical role in the function of thyroid hormones in your body.
In today’s world of soil depletion and poor nutrient intake from diets like the standard American diet, iodine deficiency is more common than once thought.
Iodine deficiency, even a relatively minor deficiency, may result in symptoms such as fatigue, hair loss, minor weight gain, and depression.
The best way to fight iodine deficiency is to use supplements that contain iodine in combination with other critical thyroid nutrients such as zinc and selenium.
Whenever possible, do your best to get iodine from natural food sources.
In most cases, supplementing is safe, and very few people experience negative side effects.
Certain conditions such as pregnancy, lactation, and smoking, can increase your risk of developing iodine deficiency because these conditions increase the demand for iodine in your body.
Most healthy adults need around 150mcg of iodine per day, but pregnant and lactating women should aim for 250-290mcg of iodine per day.
Now I want to hear from you:
Are you suffering from the symptoms of iodine deficiency?
Have you been able to tolerate iodine supplementation?
Do you also have thyroid disease?
Leave your comments below!
22 thoughts on “Early Signs of Iodine Deficiency & How it Affects Your Thyroid”
I have had my thyroid nodule for 20 yrs, Dx” hypothyroidism. I have been taking kelp 150mcg for this. TSH values have been the high end of normal. My MD knows I have been taking kelp. I have also stopped smoking for 10 months now. I feel my metabolism has slowed down, some weight gain of approx 8 pounds, since stop smoking. Any suggestions for me to get the weight gain down. I am on an exercise program, good water intake, I take HCTZ 12.5 mg fluid retention lower extremities, Metoprolol 50mg for HTN, blood pressure is stable now. Xarelto 20mg- A-Fib, which Cardiologist stated it started when I had Bronchitis April 2017, irregular heartbeats. Have had no further irregular heartbeats since being on Xarelto. I wait for your feedback. Thank you. Lynne Green email@example.com. 4/19/18 1631.
You can learn more about how to lose weight with hypothyroidism in this post: https://www.restartmed.com/lose-weight-hypothyroidism/
For the past month, I’ve been taking 250mcg of sea kelp. I noticed my heart rate was slightly increased. but I continued taking it because of all the benefits. After taking it for a month I noticed that I feel on edge. Anxiety. Along with a very high resting heart rate. I use to run 55-65 and now it is a constant 90 even while sleeping. I checked my blood pressure and it too has gone up to high levels 145/99. Now I hear my heart beat at night as well when I lay my head on my pillow. The only thing I can think of is this sea kelp vitamin I’ve been taking. Have I ruined my thyroid? I’m not going to take it anymore, but after taking it for a month, I’m afraid I did some damage. When will my heart rate come back down to normal and my blood pressure as well? Any help would be greatly appreciated.
Thanks for your article on this subject but I would ask that you question where the official RDA of iodine comes from just as you have questioned the appropriate levels of blood work. I’ve just discovered your work and am reading your back articles and appreciate all that you are doing to educate the public.
I noticed on your personal page that you ingested a lot of Mt. Dew during your residency and I wondered if you realized that it was made with bromide, which is one of the three “villains” along with chlorine and fluoride that combat the “superhero”, iodine. These four elements are all the halogens that we ingest.
It’s my opinion that the RDA of iodine was set at the minimal amount needed and not the optimal amount needed.
There was a study of the native women of New Caledonia that lends credence to this theory.
The Japanese who live on the mainland ingest about 80 times(13mg) the iodine of the RDA that you referred to, which they obtain naturally through their seaweed on a daily basis.
As a population the people who live in Japan have a longer, healthier life despite having had two atomic weapons dropped on them; having about twice as many smokers per capita as the US; having denser living conditions than the US (~1/3 of the population of the US living in an area smaller than California); and spending ~1/3 per person on healthcare than the US.
When they move to the US the Japanese adopt the US statistics with regards to breast cancer, lung cancer, and obesity, so it couldn’t be because of genetics.
In the US, you can’t purchase seaweed with the levels of iodine in it that the Japanese do on their homeland because it is blocked by the FDA.
Most of us in the US don’t get iodized salt in addition to the sea salt that you mentioned above because either our doctors told us to cut back because of the unproven causation between hypertension caused by increased salt ingestion and heart disease or we eat our meals in restaurants or processed. Restaurants and food processors don’t use iodized salt.
In my opinion, the flawed Wolff-Chaikoff (1948) study established mental blocks in the scientific community regarding iodine’s effect on the thyroid.
great observations! I use a toothpaste with nascent iodine & colloidal silver. As well, I rub a few drops of iodine on my chest from time to time. My grandmother expired from a goiter in 1927, my Father was four. Michigan is in a region of the country called the ‘Goiter Belt’~
My 19 year old daughter has had two blood tests indicating she is deficient in iodine. After much research, I’ve been told that one cannot rely on blood results at all and that she should have a urine loading test done. If blood results are false, why would any doctor order them, including her functional doctor? Thank you.
You’ll find that no test is 100% accurate in any way. It’s simply impossible to look at something floating around in the blood and make assumptions about what is happening inside the cells. Doctors use various tests to help them get an idea as to what is happening but they never give the full picture.
Hi – I understand that 150 mcg is the RDA for iodine, I’m wondering what is the absolute minimum mcg of iodine one must eat a day to stay healthy? I am on a very low sodium diet and therefore add no salt to my food; when cooking/baking I eliminate it altogether and never add it as a seasoning or for any other reason. I would estimate I’ve had a total of a tablespoon added salt in the last 8 years. My seafood intake is low, perhaps a serving of tuna once a month and I am dairy-free. I never made a connection to my diet and hypothyroidism and iodine deficiency until I was googling reasons for hair loss and discovered a link. The doctor says I’m fine – he tells me my TSH is normal (ranges from 1.02 to 2.23) and I’m getting enough iodine from what I’m eating, the body only needs a tiny bit. So I’m wondering, am I getting enough? I doubt I’m getting 150 mcg but am wondering how little would be enough to keep me going. Symptom wise – yes, good chance I am hypo but since my symptoms are so generic the real problem could be one of many things.
The RDA is set such that it fits the needs of 95% of the population. There will always be 2.5% of people who need less and 2.5% of people who need more than that RDA, though. Where you fit on that spectrum is anyone’s guess, but you will probably notice if you don’t consume enough because you may start to feel hypothyroid.
Hi Doc. I’ve been eating keto for years in December. I’ve had fabulous health benefits. #freeofDepression #freeofAnxiety #freeofSuicidalIdeation #freeofSelfHatred #freeofBrainFog #freeofFibromyalgia #freeofUnemployment #freeofRages and more. I will never go back to bread, rice, pasta, processed foods and the like. However, I’m severely low in iodine. My recent blood tests and urine test, including a thyroid panel, are ‘textbook perfect’ as is everything else. Just the iodine is a BIG problem. I eat plenty of sodium — iodized, Redmonds and Himalayan. I eat at least 20 eggs a week. I take a kelp supplement daily. I feel less than happy, have up and down emotions, no energy, and no motivation. I’ve got over 80lbs to lose (no weight loss since going keto) — 50yrs, 5’4″, female, ovulating, 110kg. I want to know if it would be safe to take iodine drops (molecular iodine colloid) and how much? Thanks for any help.
I was born RH Factor complication. Had to have blood transfusion after birth. Growing up as,a child I was very skinny, bruised very easily and often, sick more then not and suffered migraines since age 2. Dr’s could not figure out what was wrong. Until 12 years ago it was found I have Microcytic Anemia Thalassemia trait. The bone marrow is not absorbing iron and what red blood cells,are produced are extra small mutated, not able to adequately carry enough oxygen to the rest of the body, thus in turn causes a domino affect to other symptoms. Body inflammation, in turn causes diarrhea, muscles & tendons cramping, & tightening, Hypothyroidism, belly weight gain, black eyes, fatigue, brain fog, headaches. I have tried all thyroid meds but nothing worked or I had negative reactions to it. Is it possible, that its all due to the red blood cell issue? Are they connected to the thyroid?
My husband was just diagnosed with iodine deficiency. But his TSH leans on the hyper end. How can that be explained? Could he need more testing?
My iodine came back low on my blood test. I’m also on armour for low functioning thyroid. I already take your t-3 conversion supplement, but wonder if I should add an extra iodine supplement ? I have everyone of those symptoms you listed
Serum iodine tests are not accurate so I wouldn’t use that as a metric of your iodine status.
It would be great if you could address a few questions, to complete this article.
What is the best Iodine test?
What are the lab results we should have as to decide if we need to take iodine? (low, optimal and too high)
Should we take iodine with iron if we are also iron deficient, or should we wait till iron is normal and then start iodine?
I’ll write an article on that topic. In general, I don’t recommend using iodine tests because they all have limitations and just aren’t necessary.
What if you have an allergy to things like kelp, shellfish, and betadine? This there anything we can do for an iodine deficiency?
Yes, you can use supplements that contain iodine that do not have traces of those ingredients.
Interesting as my functional doctor told me to take Lugols Iodine which is a very high concentrate. She said I was very deficient in Iodine. I have ovarian cysts and fibrous breast tissue. I am also hypothyroid. I did this for a year and felt it helped immensely with my ovarian cysts. My thyroid numbers stayed the same. I did stop taking it for about one year and found when I started again I had so much more energy. During that time I stopped Lugols I was taking your supplement with Iodine in it. Is it possible that some people need the high dose like in Lugols?
There’s no question that some people benefit from high dose iodine. The issue is that there are a significant number of people who also do worse when taking higher doses which is why I generally don’t recommend the very high doses of iodine unless you know what you are doing. You can read more here: https://www.restartmed.com/high-dose-iodine/
Dr. Childs, I have had a goiter since my first trimester carring twins.
The doctor said let’s just watch and see. The twins were born good birth weight and that was the end of that. Over the years the goiter as enlargeda and now I have one on each side. Had a fine needle aspiration three different times and no cancer. Recently had iodine levels tested and yes I am deficient along with being deficient in Vitamin D3. Symptoms are dry skin, depression, thinning hair, and low energy. What is the dosage and supplement you would recommend. Want to shink multi-nodules. Thank You.
The standard dose is 150 to 300mcg of iodine per day but there’s a lot of variation in dosing. I would recommend looking at a combo such as this for your situation: