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Iodine: The Most Misunderstood Supplement For Your Thyroid

Let’s dispel the confusion about iodine supplementations for your thyroid. The truth is all in the details – as long as you are getting enough iodine from your food, no supplementation is truly necessary. Too much, or too little, can be quite harmful (whether you have thyroid disease or not). Read on to learn what makes iodine important, and you can get the right amounts for your thyroid.

Iodine’s Role In Your Thyroid

Think of your thyroid gland as a factory for thyroid hormones. Iodine is an essential building block in the factory. In other words, the human body is not able to “produce” iodine, it has to get it from food.

The thyroid gland uses iodine to create a hormone called thyroxine1. This hormone is also known as T4. T4 is then sent all over the body where tissues convert thyroxine to a more powerful hormone called triiodothyronine or T3. T3 directly stimulates every tissue in the body. T3 is responsible for engaging all cellular metabolic function.

Interested in learning more about your thyroid? We recommend you start here…

The Thyroid Reset Program - Dr. Alan Christianson

Key Insight: Since iodide is necessary for health, our body has a very strict mechanism for its regulation. For example, if too little iodine is present, the thyroid gland enlarges to have more surface area to absorb more iodine (which commonly referred to as a goiter) (1)2.

The fact is that too much iodine leads to overproduction of thyroid hormone. If left unchecked, this would lead to rapid cell turnover and excess oxidative damage. The body has a mechanism that shuts down your thyroid from accepting iodine, in order to prevent excess production of thyroid hormone. This mechanism is what we know as the “Wolff-Chaikoff effect”3.

Bottom Line: Iodide is a necessary nutrient, and thus is considered an essential nutrient. Because of its importance, iodide is highly and carefully regulated by the human body.

Is Iodine The Cause Of Thyroid Disease?

In other regions of the world, it had been observed that if iodine was endemically deficient, the levels of hypothyroidism were more prevalent. To avoid this problem, industrialized countries began fortifying table salt with iodine as a precaution4.

Unfortunately, people with thyroid disease are more sensitive to supplementation, in fact, it has been reported that levels of Hashimoto’s hypothyroidism increased in the areas where iodized salt was introduced5.

You need to know what’s in your supplements, and to take supplements you can trust. Here’s a great place to start…

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Iodine & Hyperthyroidism

When iodine levels in the body are higher than the normal levels found in nature, the thyroid begins to overproduce thyroid hormone even if the body does not need it6.

This commonly happens after patients are given drugs such as amiodarone (a drug used to control heart rate) or iodine-based contrasts often used in radiography. Unfortunately, the introduction of iodized salt and the growing popularity of supplements expose people to high levels of iodine every day.

Some symptoms of hyperthyroidism include:

  • Nervousness
  • Heart palpitations
  • Hair loss
  • Heat intolerance
  • Osteopenia
  • Excessive hunger

Bottom Line: It is true that drugs can predispose people to excess iodine, but iodized salt and supplements are sources of iodine that should definitely be acknowledged. These excess amounts of iodine signal the thyroid to create more hormone – predisposing you to hyperthyroidism.

Iodine & Hypothyroidism

High levels of iodine can cause your thyroid to “shut-off.” In a study, it was observed that 18% of people who received iodine-based contrast for radiography had an increase in their TSH levels7.

This is especially concerning for people with autoimmune thyroiditis (like Hashimoto’s disease) and thyroid operations because the body tries to protect the already stressed thyroid and it shuts it off by way of the previously mentioned Wolff-Chaikoff effect8.

Iodine hypothyroidism is also seen in patients that take supplements with iodine9,10. You can imagine how frustrating this can be, you may be trying to help your thyroid problem and you decide to increase your levels of iodine, but in fact, taking too much iodine may make your thyroid problem worse.

Bottom Line: Excess amounts of iodine can cause both hypothyroid and hyperthyroid, which is why you should keep your iodine levels to natural levels (like the ones found in natural foods).

Not Too Little, Not Too Much

Fortunately, in the United States, the addition of iodine to table salt was very effective in correcting iodine deficiency. In fact, in 1920, measures were taken to lower the intake of iodine in the United States11.

The dietary recommendations for iodine intake are 150 mcg for adults with slightly higher numbers for women who are pregnant or breastfeeding. This is easily obtained through a nutrient-dense diet.

For example, a cup of plain yogurt can supply around 56 mcg of iodine, a single serving of cod can provide you with 87 mcg of iodine. As you can see, a nutrient dense diet can provide easily with enough iodine for proper thyroid function.

In contrast, a single teaspoon of iodized salt contains 380 mcg of iodine! For this reason, we recommend our patients avoid processed salt and opt for natural occurring salts such as Himalayan Pink Salt or Celtic Salt.

Taking Thyroid Hormone?

Thyroid hormone medicine contains iodine, which is why we recommend using well-standardized thyroid medications to avoid excess iodine consumption.

Armor Thyroid is standardized to iodine content not hormonal content and can contain anywhere from 0.17% to 0.23% iodine. We prefer thyroid medications that are standardized to hormonal content like NatureThroid and WP Thyroid.

Secondly, excess iodine from supplements or food has to be excreted through our sweat and urine. If you have problems with detoxification, having too much iodine can be a problem and could put you in a hypothyroid or hyperthyroid state.

Bottom Line: It is for this reason that all of our supplements are iodine-free.

Can Iodine Cause Thyroid Problems?

We have written about excess iodine extensively over the years, and we believe that there is a lot of misinformation on this important micronutrient. If you would like to educate yourself more on this subject, you can feel free to start reading more about iodine and thyroid health today (2).

Interested in learning about your thyroid, more generally? Please feel free to take the Thyroid Quiz (3) today, to give yourself a big-picture understanding of this incredibly important part of your body.

1. Roti E, Uberti ED. Iodine Excess and Hyperthyroidism. Thyroid. 2001;11(5):493-500. doi:10.1089/105072501300176453.
2. Kirsten D. The Thyroid Gland: Physiology and Pathophysiology. Neonatal Netw J Neonatal Nurs. 2000;19(8):11-26. doi:10.1891/0730-0832.19.8.11.
3. Markou K, Georgopoulos N, Kyriazopoulou V, Vagenakis AG. Iodine-Induced Hypothyroidism. Thyroid. 2001;11(5):501-510. doi:10.1089/105072501300176462.
4. Zimmermann MB. Iodine Deficiency. Endocr Rev. 2009;30(4):376-408. doi:10.1210/er.2009-0011.
5. Camargo RYA, Tomimori EK, Neves SC, et al. Thyroid and the environment: exposure to excessive nutritional iodine increases the prevalence of thyroid disorders in Sao Paulo, Brazil. Eur J Endocrinol. 2008;159(3):293-299. doi:10.1530/EJE-08-0192.
6. Stanbury JB, Ermans AE, Bourdoux P, et al. Iodine-induced hyperthyroidism: occurrence and epidemiology. Thyroid. 1998;8(1):83-100. doi:10.1089/thy.1998.8.83.
7. Gartner W, Weissel M. Do iodine-containing contrast media induce clinically relevant changes in thyroid function parameters of euthyroid patients within the first week? Thyroid. 2004;14(7):521-524. doi:10.1089/1050725041517075.
8. Bürgi H. Iodine excess. Best Pract Res Clin Endocrinol Metab. 2010;24(1):107-115. doi:10.1016/j.beem.2009.08.010.
9. Teng W, Shan Z, Teng X, et al. Effect of iodine intake on thyroid diseases in China. N Engl J Med. 2006;354(26):2783-2793. doi:10.1056/NEJMoa054022.
10. Pedersen IB, Laurberg P, Knudsen N, et al. An increased incidence of overt hypothyroidism after iodine fortification of salt in Denmark: a prospective population study. J Clin Endocrinol Metab. 2007;92(8):3122-3127. doi:10.1210/jc.2007-0732.
11. Li M, Li M, Eastman CJ. The changing epidemiology of iodine deficiency. Nat Publ Gr. 2012;doi(10). doi:10.1038/nrendo.2012.43.

Written by Dr. Guillermo Ruiz of Integrative Health. Dr. Ruiz is an Associate Physician with Integrative Health, interested in the treatment of endocrine disease with a focus on thyroid health. Under the mentorship of Dr. Alan Christianson, Dr. Ruiz expanded his knowledge on the treatment of Hashimoto’s and Grave’s disease and has completed advanced endocrinology training in order to better address and resolve endocrine disease.

Learn more about Dr. Ruiz here