Updated: Apr 26, 2019
If you are like many of my health-conscious patients who seek to eat a wholesome diet, you may be at risk for iodine deficiency. Iodine deficiency was a common problem until the 1920s when they started adding iodine to salt. Then the problem virtually went away. Now iodine deficiency is making a comeback because many people avoid salt, and when they do use salt, they opt for Himalayan sea salt, Celtic sea salt, and other forms of sea salt—which are not fortified with iodine. Iodine was once used in the commercial bread-making process, but now bromide is used instead. Bromide may worsen the problem because bromide, chloride, and other halogens displace iodine. With concerns about mercury toxicity, people are eating less and less seafood, which is one of nature’s richest sources of iodine. For all of these reasons, it is the most health-conscious individuals who are the greatest risk for iodine deficiency.
The latest statistics show that 36% of women of childbearing age in the United States do not consume enough iodine, and 15% have moderate-to-severe iodine deficiency. Why is this happening, why should we care, and what can we do about it?
What is iodine?
Iodine is a vital trace mineral that is essential for thyroid hormone production and metabolism. Most iodine in the body is sequestered in the thyroid gland, but iodine also accumulates in the breast tissue, eyes, salivary glands, ovaries, and the mucosa of the stomach.
In addition to its central role in thyroid hormone production, iodine also influences estrogen metabolism and acts as an antioxidant. Iodine is a useful therapy to relieve symptoms of fibrocystic breast disease and may reduce the risk of breast cancer. 
Iodine is critical for development of the nervous system in utero. Babies who are born with iodine deficiency have a lowered IQ or a severe condition called cretinism, leading to developmental delays and mental disabilities.  Iodine deficiency in children and adults is characterized by a goiter, or enlarged thyroid gland.
Clearly iodine is a mineral we do not want to lack.
What foods supply iodine?
Seaweed and Seafood
Iodine is found mostly along coastal areas and in seawater, making seaweed and seafood the richest food sources. With concerns over heavy metals and toxins in fish, health-conscious individuals are eating less and less of these iodine-rich foods.
Before the 1920s, obvious goiters were present in 26% to 70% of children in certain areas of the United States: the Great Lakes, the Appalachians, and the Northwestern regions were known as the “goiter belt.” Then in a public health initiative to address endemic goiter, the first iodized salt became available on US grocery store shelves in 1924. Iodized salt has been a huge public health success, and about 120 countries have adopted programs that require iodine be added to salt. Fortification of salt in the US is not mandatory, however. It is completely voluntary. Most processed foods are made with salt that is not iodized. This means that the primary source of iodized salt is household use. Himalayan sea salt or other forms of sea salt provide an array of trace minerals but do not provide adequate amounts of iodine.
Small amounts of iodine are present in plant foods, but the amount depends on the amount of iodine in the soil and groundwater used for irrigation. Most foods in the United States are grown inland and accumulate negligible amounts of iodine. Plant-based diets are promoted as a healthy pattern of eating, but we must be purposeful in eating foods like seaweed that will provide sufficient iodine.
For more information on what to eat, click here.
How much iodine is too much?
The recommended daily intake of iodine is 150mcg for men and women who are not pregnant, 220mcg during pregnancy, and 290mcg while breastfeeding. One teaspoon of iodized salt provides about 400mcg of iodine. A typical multivitamin provides 150 to 200mcg of iodine per day. For patients who are deficient in iodine, we offer a supplement that provides an amount as high as 12.5mg.
There is some controversy over how much iodine is too much. The American Thyroid Association warns the general public not to consume more than 500mcg per day of iodine and says that 1100mcg per day might create thyroid disease. Some say that excessive intake of iodine might trigger Hashimoto’s disease and aggravate existing thyroid disease.   The risks of taking too much iodine can be virtually eliminated by taking iodine along with selenium and by working with a physician to be sure that you are taking the right amount for your body.
How do I know if I need more iodine?
The best way to determine if you are iodine-deficient is to test your levels. With a urine test. We offer this test to our patients and always recommend testing before taking an iodine supplement. (If you are interested in this test, schedule an appointment with one of our nutritionists here)
Iodine is such a vital nutrient for health. It is required for health of the thyroid, breasts, and other organs. Iodine deficiency is making a comeback, and it is happening more and more in the most health-conscious individuals. Do yourself a favor and get your levels checked today.
Call our office to schedule a consultation today: 303-343-3121
You may also be interested in:
 Caldwell KL, Jones R, Hollowell JG. Urinary iodine concentration: United States National Health And Nutrition Examination Survey 2001-2002. Thyroid. 2005;15(7):692-699.
 Patrick L. Iodine: deficiency and therapeutic considerations. Altern Med Rev. 2008;13(2):116-127.
 Ghent WR, Eskin BA, Low DA, Hill LP. Iodine replacement in fibrocystic disease of the breast. Can J Surg. 1993;36(5):453-460.
 Smyth PP. The thyroid, iodine and breast cancer. Breast Cancer Res. 2003;5235-238.
 Doggui R, El Atia J. Iodine deficiency: Physiological, clinical and epidemiological features, and pre-analytical considerations. Ann Endocrinol (Paris). 2015;76(1):59-66.
 Leung AM, Braverman LE, Pearce EN. History of U.S. iodine fortification and supplementation. Nutrients. 2012;4(11):1740-1746.
 Ajjan RA, Weetman AP. The Pathogenesis of Hashimoto’s Thyroiditis: Further Developments in our Understanding. Horm Metab Res. 2015;47(10):702-710.
 Fiore E, Latrofa F, Vitti P. Iodine, thyroid autoimmunity and cancer. Eur Thyroid J. 2015;4(1):26-35.
 Prete A, Paragliola RM, Corsello SM. Iodine Supplementation: Usage “with a Grain of Salt”. Int J Endocrinol. 2015;2015312305.
 Negro R. Selenium and thyroid autoimmunity. Biologics : Targets & Therapy. 2008;2(2):265-273.
 Soldin OP. Controversies in urinary iodine determinations. Clin Biochem. 2002;35(8):575-579.
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About The Care Group: We promote optimal wellness by providing an individualized, functional medicine approach to address root causes rather than simply treating symptoms. We help patients with a wide range of issues including autoimmune/ inflammatory disease, digestive disorders, hormone imbalances, and mood disorders. To learn more about our practice, click here.
About the Author: Dr. Gerard Guillory, MD is Board Certified in Internal Medicine and has published two books on Irritable Bowel Syndrome (IBS). In 1985, he opened The Care Group, PC. Today, his clinic is a Primary Care facility that is a hybrid of functional and traditional medicine treating patients with digestive disorders, autoimmune disease, and other conditions. You can learn more about Dr. Guillory here.