Learn to love your thyroid gland- a metabolic maestro that regulates growth and metabolism. Your thyroid must be working properly for you to maintain a healthy weight. One of the most important micronutrients to nourish your thyroid- and with it, healthy energy levels, tissue repair, and waistline- is iodine, a lesser known but highly important mineral!

Iodine supports tissue growth and is critical in the womb and throughout our lives. You may have heard of iodized salt- the processed food that helps our population avoid widespread iodine deficiency. So why is iodine so important? Read on to learn more about this metabolism-boosting mineral – what it does, why you should care, who may be deficient, and where you can get it!

Iodine Deficiency Increases Disease Risk

The oldest known documentation of using iodine for medicine comes from China in 3600 BCE: using seaweed and burnt sea sponges to cure goiter. Although at that time the mineral had not been isolated, the use of sea vegetables as a remedy for goiter continued for thousands of years. In 1813, Joseph Louis Gay-Lussac published the first paper presenting this new element, named iodine after the Greek word ioeides (“violet”), and over the next several decades, research continued to reveal the connection between iodine and goiter. Finally, in 1896, Eugen Baumann reported the discovery of iodine in the thyroid gland, and our current understanding evolved from there.[1] Most of the 20 to 30 milligrams of iodine that your body contains is in your thyroid gland; smaller quantities of iodine are also found in the mammary and salivary glands, eyes, cervix, stomach lining, and blood.

In the 1830s, the French nutritional chemist Jean Baptiste Boussingault suggested iodizing salt to reduce the incidence of goiter. Because iodine naturally occurs in salt found in the Earth’s upper crust and goiter was not found in people consuming it, iodizing salt was a logical way to increase iodine intake in areas where goiter was common. Iodizing salt was not, in the 1800s, a cheap activity, so this accepted idea wasn’t actually implemented until the early 1920s, starting with the United States and Switzerland.[2] Data supporting the value of fortification was stunning: in 1917, for instance, David Marine, a physician in Ohio, showed that 2100 schoolgirls treated with iodine had 0.2% incidence of goiter compared with over 25% in children without iodine supplementation.[3] Iodized salt has been available ever since May of 1924, when iodized salt first hit the shelves in Michigan, a state in the heart of the iodine-deficient “goiter belt.” Although over 90 percent of the United States currently has access to iodized salt, it is estimated that only 70-76% of households consume iodized salt, a number stable since the 1950s.[4]

Signs of iodine deficiency include:

  • Extreme iodine deficiency during pregnancy can cause a fetus to develop cretinism, a syndrome pairing thyroid failure with brain damage and mental retardation. This occurs primarily due to iodine deficiency in the fetus and secondarily due to the mother’s lack of thyroid hormone.[5] Cretinism is a developmental syndrome with irreversible effects and mom’s micronutrient status is very, very important!
  • [6] You may be interested to know that both too much and too little iodine can cause goiter, though the most common condition is to have too little. Goiter is a large lump in the throat that occurs when the thyroid gland expands dramatically in size. The thyroid filters your blood and sifts out the iodine it needs. With too much iodine, it gets bigger to process it. With too little iodine, it gets bigger to sift more blood more quickly in a desperate effort to collect what little iodine is there.
  • Depression and mental lethargy. In children, these symptoms may be linked to iodine deficiency during development. In adults, iodine deficiency is linked to subclinical or overt hypothyroidism due to less thyroid hormone production. Depression is a classic symptom.
  • Weakness and fatigue. As your master thermostat, your thyroid helps to control energy regulation in your cells. When that system derails, your energy levels can plummet.
  • Weight gain. Turning down the dial on thyroid activity means you decrease body temperature, use less energy, and gain weight. Think of these changes like going into a lockdown hibernation mode to conserve energy. While you may appreciate that this response can keep you alive in a state of energy and/or nutrient deficiency, it certainly doesn’t do much good for your waistline!
  • Slow wound healing. Iodine helps to stimulate the growth of new cells. Your overall metabolic rate, regulated by thyroid activity, primarily regulates the speed at which your tissues turn over.

Are You At High Risk For Iodine Deficiency?

Most people deficient in iodine simply do not consume enough.[7] Beyond inadequate intake, people at the greatest risk of iodine deficiency include:

  • People who live in an area with iodine-deficient soil (such as the iodine deficiency belt across the Northern United States)
  • People who consume low salt diets
  • People who consume a “Standard American Diet”
  • People who consume vegan or vegetarian diets
  • People who do not consume seafood

Benefits of Getting Enough Iodine

Iodine is essential for growth and repair, performing many key functions:

  • Revs your Thyroid! Your body primarily uses iodine to make the T4 (thyroxine) and T3 (triiodothyronine) hormones you need to grow, develop, and regulate your daily systems. Your thyroid affects important processes like reproduction, body temperature regulation, fuel usage, neuromuscular function, protein synthesis, and even skin and hair growth. Damage to the thyroid from other sources or insufficient iodine can reduce one’s metabolic rate by up to 55 percent, resulting in weight gain, a lower body temperature, and slow tissue repair.
  • Stimulates Growth and Brain Development. If you are planning on becoming pregnant, listen to this – iodine requirements increase by over 50% during pregnancy and lactation! Iodine deficiency during pregnancy can cause hypothyroidism in both mother and fetus and impair brain development. In fact, every level of iodine deficiency- mild, moderate, and severe- can have life-altering negative impacts on your child’s cognitive ability.[8] When deficiency is severe enough, a child is born with cretinism. Cretinism can be completely eliminated with appropriate iodine levels during early pregnancy, which is also associated with better birth weight, improved development scores and infant mortality, and better maternal mortality.[9] Considering the role that a healthy thyroid plays in stable blood sugar, immunity, and mood, it is likely that iodine deficiency could increase the likelihood of postpartum depression.
  • Cognitive Capacity and Mood. Due to its role in mental development, iodine has been shown to be critical for improving cognitive ability. A healthy thyroid boasts more stable blood sugar and serotonin production, both of which support a stable mood. Iodine population studies in meta-analyses determined that iodine deficient populations have an average drop in IQ scores of 12 to 13.5 points![10]
  • Speeds Wound Healing. In addition to supporting cell growth and speeding your damage repair, iodine is often used in first aid to disinfect topical wounds. This antimicrobial ability of iodine makes it popular to sterilize water in otherwise undrinkable situations.

Considering its many roles, iodine may be used in the prevention and/or treatment of cancer, chronic fatigue, depression, obesity, hypothyroidism, and goiter! With all these amazing benefits of adequate iodine status, let’s break down how to get it with a focus on foods, mindful lifestyle choices, and smart supplementation.

Ingest Some Iodine!

STEP ONE – FOOD: Choose foods rich in iodine – and don’t necessarily skip the salt.

  • Choose foods rich in iodine. Iodized table salt is the main source of iodine in the U.S. diet, but seafoods, especially sea vegetables (seaweeds), have the most naturally occuring iodine. Great sources include cod, kelp, kombu, and digitata, but all seafood contains some iodine. Lesser but meaningful sources of iodine include dairy foods (especially milk and yogurt), as well as eggs, unpeeled potatoes, turkey, navy beans, and strawberries. At the end of the day, though, if you do not consume seafood, you will need to consume iodized salt or supplement to ensure your iodine needs are met. In some parts of the world where it is not practical to use iodized salt, other common foods (like bread) may be fortified with iodine. Processed foods containing the red coloring agent erythrosine (aka. Red No. 3) also contain significant amounts of iodine, though we are certainly not advocating brightly dyed red foods.
  • Savor the sea. Consider diversifying your iodine intake from multiple seafood sources. For instance, add seaweed to your soups, stocks, smoothies, grains, or beans to make a thicker, smoother texture loaded with iodine and other healthy electrolytes. Choose kelp, digitata, kombu, and other thick seaweeds (like nori, for instance) to get your iodine levels met with great ease.[11] Grind kelp and mix it half and half in your salt shaker to use less salt and get more iodine per shake! With no seafood intake, vegan and vegetarian diets are associated with iodine deficiency, although vegans could make friends with seaweed and certainly get all the iodine they need naturally.
  • Curb the competition. Consider that bromine and fluorine, chemically, are very similar to iodine. They can compete with iodine in your body and lead to lower iodine levels in your thyroid. Bromine is found in non-organic white flour that has been “brominated,” which is most white flour in the United States. Fluoride has its own fortification history, but excess levels may be encountered in certain waters, ingestion of fluoride-filled toothpastes, and excessive consumption of black tea.[12] The order of reactivity is fluorine, then bromine, then iodine, meaning that fluorine and bromine will compete with iodine for absorption and displace it, but iodine does not react strongly enough to displace them, so exposure to these elements may compromise iodine levels.[13]
  • Say Maybe to Soy. Soy is called a goitrogen- a food that can cause goiter- because isoflavones have been shown to interfere with your thyroid’s ability to use iodine, meaning those at high risk for hypothyroidism or those with hypothyroidism should avoid soy. For those choosing soy for other reasons, such as its robust phytoestrogen content, consider reducing your use of this food, increase your iodine intake, and strive for balance.
  • Consider your cooking methods. Iodine is lost to the air when heated without water, so prepare iodine-rich foods in water to make the most of it. Making soups, stocks, and slow cooker meals with added seaweed is one of the best ways to avoid losing iodine while cooking.

STEP TWO – LIFESTYLE: Consider your digestion, medications, and overall health to support your iodine status.

  • Reduce your Bromine Exposure. Many household chemicals can be toxic in some way to the human body, and excessive bromine exposure is no exception. Bromine is common in flame retardants (consider your pillows and other flame-free fabrics) and pesticides, so while a gluten-free diet will eliminate the bromine in wheat flour it won’t eliminate your exposure entirely.
  • Mind your Medications. Amiodarone (Cordarone), a cardiovascular medication, contains iodine and for some may disrupt thyroid function. Dentist-prescribed high-fluoride toothpastes, while great for boosting dental enamel, may cause excessive fluoride absorption while reducing iodine absorption.

STEP THREE – SUPPLEMENTATION: Iodine is essential- but don’t overdo it.

  • Avoid excessive supplementation of iodine. Iodine toxicity can cause goiter and thyroid dysfunction as well. Luckily, iodine toxicity is rare. While iodine is a relatively benign trace element, we recommend sticking to the RDI of 150 micrograms per day. The tolerable upper level intake for iodine is set at 1100 micrograms per day because that level can cause hyperthyroidism.[14]
  • Seek Synergy. Nutrients can support each other’s activities, and a deficiency in vitamin A, vitamin E, iron, or zinc will exacerbate an iodine deficiency. In addition, adequate selenium levels help you make iodine available to your thyroid, so a selenium deficiency can slow thyroid activity- and act much like an iodine deficiency.
  • Choose beneficial forms. Potassium iodide, sodium iodide, iodine caseinate, elemental iodine, and kelp are commonly supplemented forms. Because of potenital contamination issues with kelp, we provide potassium iodide in Nutreince, which is safe and very easy to absorb.
  • Roll with the Recommended Daily Intake (RDI). The adult RDI for iodine is 150 mcg, the amount we provide in Nutreince. Because we can obtain iodine from a balanced diet, the RDI is a good insurance policy and more should not be necessary to obtain micronutrient sufficiency- unless you know you are at high risk of deficiency. Planning on getting pregnant? Because iodine is required for normal brain development in utero and during the early postpartum period, the recommended intake in the United States jumps to 220 micrograms during pregnancy and 290 micrograms during lactation,[15] while the WHO simply recommends 250 micrograms of iodine during both pregnancy and lactation.[16]

For anyone who wants to maintain healthy energy levels, grow and repair tissues effectively, and maintain a healthy weight, iodine is an essential mineral that should not be ignored. Enjoy the foods of the sea, add a bit of iodized salt your home-cooked meals, or supplement regularly with a well formulated multivitamin like Nutreince to avoid missing out on this mineral! Interested in learning more about micronutrients? Curl up in a warm bath with a brand new copy of Micronutrient Miracle!


[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3509517/

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3509517/

[3] https://www.ncbi.nlm.nih.gov/pubmed/18936198/

[4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3509517/

[5] https://www.ncbi.nlm.nih.gov/pubmed/10828176

[6] https://www.ncbi.nlm.nih.gov/pubmed/23750439

[7] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3724376/

[8] https://www.ncbi.nlm.nih.gov/pubmed/10828176

[9] https://www.ncbi.nlm.nih.gov/pubmed/22742605

[10] https://www.ncbi.nlm.nih.gov/pubmed/22742605

[11] https://thyroidresearchjournal.biomedcentral.com/articles/10.1186/1756-6614-4-14

[12] https://www.ncbi.nlm.nih.gov/pubmed/21593111

[13] https://www.britannica.com/science/halogen-element

[14] https://www.nap.edu/read/10026/chapter/10

[15] https://ods.od.nih.gov/factsheets/Iodine-HealthProfessional

[16] https://apps.who.int/iris/bitstream/handle/10665/61278/WHO_NHD_01.1.pdf