Iodine: An In-Depth Guide To Its Potential Benefits



  • Iodine is abundant in foods like sea vegetables and grass fed yogurt, but it can also be found in high-quality supplements
  • This mineral is needed by your body to produce thyroid hormones essential for optimal function. Iodine also helps ensure proper fetal and infant development
  • Sadly, iodine deficiency is a rising problem in many parts of the world due to multiple environmental and lifestyle factors

Maintaining optimal iodine levels has been recommended by researchers1 and health experts alike.2But you may wonder: What makes iodine so important for your body, and why is a deficiency of it considered alarming?

What is iodine?

Iodine is a trace element mineral that can be sourced from foods, although it’s also found in potassium iodide or sodium iodide supplements, or used in multivitamin, mineral or dietary supplements (like iodine-containing kelp).3 According to an Indian Journal of Endocrinology and Metabolism article, 15 to 20 milligrams of this element are found in your body, with 70% to 80% in your thyroid gland.4

There are multiple types of iodine. The American Thyroid Association (ATA) explains that when it’s in the form of iodide, iodine is made into two radioactive forms: iodine-123 or I-123 (harmless to thyroid cells), and iodine-131 or I-131 (harmful to thyroid cells). Both are used in people with thyroid diseases, and given orally in pill or liquid form.5 If you want to know where your iodine levels stand, you doctor may recommend that you undergo a urine or blood test.6

Don’t confuse active forms of the chemical element iodine7 with that found in table salt, even if the label says it contains iodine because iodized table salt is technically potassium iodide8 added to sodium chloride, the chemical name for table salt.9

The same principle applies if you encounter povidone iodine. This substance, commonly known by the brand name Betadine10 and used topically as an antiseptic,11 is composed of iodine and a synthetic polymer called polyvinylpyrrolidone or povidone.12

A brief history of iodine

Did you know that iodine was accidentally discovered? A French chemist named Bernard Courtois discovered iodine in 1811, while helping his father manufacture saltpeter, an ingredient used in gunpowder. After running out of wood ash, which was their source of potassium nitrate, Courtois burned seaweed instead, then washed the ash with water.

However, he added too much sulfuric acid to the washed ashes, and a cloud of violet gas appeared from the ashes. When it condensed, purple crystals appeared on a cold surface.

Suspecting it might be a new element, Courtois took the crystals to other scientists to examine. When they confirmed that, indeed, it was a new element, a French chemist named Joseph Louis Gay-Lussac named it “iode,” from the Greek word ioeidēs meaning “violet-colored.”13

Why iodine deficiency is alarmingly rising

Iodine deficiency is a rising problem worldwide, affecting 2.2 billion people, predominantly in countries where iodized salt is not available.14,15 According to the ATA, average urinary iodine levels (which may be utilized to measure dietary iodine intake16), have dropped by half since the 1970s.17There are nutritional and environmental factors linked to an iodine deficiency, namely:18

Shifts in food preparation and consumption — More Americans are consuming prepackaged and ready-to-eat foods or eating in restaurants, instead of preparing home-cooked meals. This increases their exposure to high-salt foods that may not have sufficient amounts of iodine.

Thiocyanates in foods — Thiocyanates are metabolites19 found in vegetables from the Brassica family, as well as in cassava and soy. Frequent consumption of high-thiocyanate foods, according to the World’s Healthiest Foods, may disrupt your thyroid gland’s ability to process iodine. This may cause you to think you’re dealing with an iodine deficiency, even if the problem isn’t present at all.

Iodine-deficient soils — In North America overuse of alkaline fertilizer and intensive cropping contributes to iodine depletion in the soils, which then prevents food crops from getting iodine naturally from the soil.20 In the Midwest in the U.S., soils are lacking in iodine anyway, due to their distance from ocean waters.21

There are also certain groups who may be at risk for an iodine deficiency:22

Vegans and vegetarians23 — Authors of an Annals of Nutrition and Metabolism article highlighted that plant-based foods have fewer iodine contents than animal-based products.24

Pregnant women — Iodine facilitates thyroid production essential for the baby, although the mineral is oftentimes released through the mother’s urine.25 Some studies showed that pregnant women in countries like Brazil,26 China,27 Ethiopia28 and Ghana29 aren’t getting sufficient amounts of iodine.

People living in regions with iodine-deficient soils and who eat mostly locally grown foods — Soils in these areas tend to have low iodine levels, producing crops that have few amounts of this mineral. The Himalayas, the Alps and the Andes regions and some river valleys in south and southeast Asia tend to have the most iodine-deficient soils.30

In the early 20th century, certain areas of the U.S. were once known as “goiter belts” because regional soils were so lacking in iodine that up to 70% of children had goiter, a symptom of iodine deficiency. An iodine supplement program in the affected regions — the Appalachians, Great Lakes and Northwestern areas — and the introduction of iodized salt in 1924 addressed the issue.31

People consuming fewer amounts of iodine — Increasing iodine levels should be done via your diet since the body doesn’t produce it. If you don’t consume enough iodine-rich foods, this could lead to an iodine deficiency.32

People who eat foods containing goitrogens — These are naturally occurring substances33that could negatively impact your body’s usage of iodine. They’re present in soy and cruciferous vegetables like cabbagebroccolicauliflower and Brussels sprouts.

An iodine deficiency can also be problematic since it can lead to your body’s inability to make sufficient amounts of the thyroid hormone. This can lead to negative effects like:34

  • Inhibited growth, brain development35,36 and sexual progression in babies born to an iodine-deficient mother
  • Very low IQ levels in infants and children
  • Reduced ability to work and think clearly among adults
  • Increased risk for brain damage37

Some iodine deficiency symptoms to watch out for include:

  • Swelling of the thyroid glands in the neck,38producing a visible lump called a goiter39
  • Weakness or tiredness
  • Weight gain
  • Hair loss
  • Dry skin
  • Increased tendency to feel cold
  • Slower heart rate
  • Cognitive issues like low IQ levels and trouble learning40
  • Hypothyroidism or low thyroid levels41

An iodine deficiency can also trigger a rare but life-threatening hypothyroidism complication called myxedema. Warning signs include unconsciousness, goiter, reduced energy levels, seizures, confusion and coma.42 Myxedema requires immediate medical treatment, so if you notice someone exhibiting these symptoms, seek medical attention right away.43

Iodine rich-foods to try

To help manage your iodine levels, there are various foods high in this nutrient you can add to your diet, namely:

Sea vegetables like kelp, nori, kombu and wakame44  Iodine is highly abundant in the Earth’s oceans, especially among these sea vegetables.45 According to this 2014 study, out of the different seaweed varieties, kombu had the highest iodine content, followed by wakame and then nori.46

Organically grown cranberries or fresh cranberry juice — One ounce of cranberries (about one-third cup) contains 100 micrograms of iodine.47 Ideally, consume fresh and organic cranberries in moderation because they do contain 4.27 grams of fructose per cup.48 If you want cranberry juice, make your own drink at home, without added sugars, or by adding Stevia to it.

One caveat: If you’re struggling with kidney stones, avoid consuming cranberry products because they contain oxalates that may trigger development of more stones.49 Mayo Clinic also advises that you avoid drinking cranberry juice if you’re taking warfarin (an anticoagulant medicine), because it may enhance this drug’s effects and increase your bleeding risk.50

Yogurt made from organic and grass fed milk51  Apart from being a good source of iodine,52organic, grass fed yogurt is a good source of probiotics.

Iodine’s uses and health benefits

Your body needs iodine to facilitate production of thyroid hormones that aid in maintaining optimal metabolism and other important functions. This mineral, according to the National Institute of Health’s Office of Dietary Supplements, is particularly important if you’re pregnant or breastfeeding,53since it can help babies grow and develop properly.54

Breast milk is a good iodine source for babies.55 However, the amount of iodine in breast milk relies on the mother’s intake of this mineral. According to WebMD, iodine may also:56

  • Help inhibit iodine deficiency and complications linked to it
  • Relieve cutaneous sporotrichosis, a skin disease caused by the Sporothrix fungus57
  • Address fibrocystic breast disease
  • Alleviate diabetic ulcers
  • Deliver expectorant capabilities
  • Lower someone’s risk for eye disease, diabetes, heart disease and stroke
  • Eliminate fungi, bacteria and amoebas
  • Purify water

Topical iodine applications may also aid in eliminating germs and reducing your risk for chemotherapy-caused mucositis, or soreness inside the mouth.58

Studies on iodine

One study found that iodine may help reduce the risk of cardiovascular diseases like hypercholesterolemia. The study, published in The Journal of Nutrition in September 2015, noted that iodine supplementation may reduce hypercholesterolemia risk in overweight women with a moderate to severe iodine deficiency.59

As mentioned above, iodine is also crucial to a child’s well-being, as iodine deficiency may lead to impaired neurodevelopment in children. According to a July 2017 study in The Journal of Nutrition, women whose maternal iodine intake levels fell below the Estimated Average Requirement during their pregnancy may bear children who’ll develop issues like language delays, behavior problems and decreased fine motor skills once they turn 3 years old.60

Furthermore, being deficient in this mineral may increase the risk for thyroid cancer. Results from a study published in Thyroid Research in June 2015 suggested that an iodine deficiency is a possible risk factor for thyroid cancer, follicular thyroid cancer (FTC) and anaplastic thyroid cancer (ATC).61

Iodine side effects to watch out for

If you’re interested in taking iodine supplements, it’s imperative to talk to your doctor to determine the ideal dosage for your condition. This may help lessen your risk for adverse effects like iodine overdose and acute iodine poisoning.62

Consuming high amounts of iodine can lead to hypothyroidism,63 which may block thyroid hormone production. Other side effects of taking a very large dose of iodine include:64

  • Goiter, or enlarged thyroid gland
  • Thyroid gland inflammation
  • Higher risk for thyroid cancer
  • Metallic taste
  • Soreness of teeth and gums
  • Worsening of conditions like hypothyroidism, goiter or thyroid tumor65
  • Burning sensations in your mouth, throat and stomach
  • Fever
  • Stomach pain
  • Nausea
  • Vomiting
  • Diarrhea
  • Weak pulse
  • Coma

Some people may not tolerate iodine or products containing it, like those diagnosed with an autoimmune thyroid disease. If you’re sensitive to iodine, the following complications could develop:66

  • Severe bleeding and bruising
  • Joint pain
  • Face and lip swelling
  • Contact dermatitis, a type of itchy rash that gradually develops
  • Urticaria or hives67

If you’re struggling with a rash called dermatitis herpetiformis, be aware that iodine could exacerbate this health issue.68 Medical News Today adds that an iodine intolerance may be fatal since it might trigger anaphylaxis, which could progress into a life-threatening anaphylactic shock. This is a sudden allergic reaction characterized by hives, low blood pressure, dizziness or lightheadedness, palpitations and breathing difficulties.69

According to the National Institutes of Health’s Office of Dietary Supplements, there can also be instances wherein iodine supplements may interact with medicines you’re taking:70

Anti-hyperthyroidism medicines like Methimazole (Tapazole) — Taking iodine supplements alongside antithyroid medications may deplete your body’s production of this important hormone.

ACE inhibitors like benazepril (Lotensin), lisinopril (Prinivil and Zestril) and fosinopril (Monopril) — ACE inhibitors are recommended for people with high blood pressure levels. If you take iodine supplements alongside ACE inhibitors, there’s a risk that the potassium in your blood may rise to an unsafe level.

Potassium-sparing diuretics like spironolactone (Aldactone) and amiloride (Midamore) —Using potassium iodide supplements together with potassium-sparing diuretics can significantly raise your blood’s potassium content.

Inform your doctor before using iodine supplements, especially if you have a medical condition, so they can advise whether your current medicine will interact with the supplement without causing any side effect.

Iodine is an effective mineral for your health

Iodine is crucial in maintaining ideal health and well-being, but most people take it for granted and don’t monitor their daily intake of this mineral. This leads to iodine deficiency, which now affects millions of people globally.

You can avoid iodine deficiency by eating iodine-rich foods or taking high-quality supplements and multivitamins containing this mineral. However, always exercise caution about raising your iodine intake, since this mineral has been linked to side effects, some of which are life-threatening and could exacerbate your condition.

Frequently asked questions (FAQs) about iodine:

Q: What does iodine do?

A: Your body needs iodine because this mineral can help:71

Produce vital thyroid hormones

Promote babies’ development

Improve cognitive function during childhood

Lessen risk for radiation-induced thyroid cancer


Q: What is iodine used for?

A: Some of iodine’s uses include:72

Acting as an expectorant

Removing fungi, bacteria and amoebas from your body

Purifying water

Alleviating fibrocystic breast disease

Helping address cutaneous sporotrichosis, which is a skin disease caused by the Sporothrix fungus73

Q: Is iodine a metal?


A: According to LiveScience, iodine is a nonmetal, although it does exhibit some metallic qualities.74

Q: Where do you get iodine?

A: You can increase your body’s iodine stores by consuming foods high in iodine or taking high-quality supplements or multivitamins containing this mineral.75

Q: What foods have iodine?

A: Iodine-rich foods you can add to your diet include kelp, nori, wakame and other sea vegetables,76 organically grown cranberries or fresh cranberry juice77 and grass fed yogurt.78,79

Q: Does sea salt have iodine?

A: Yes, but in very low qualities.80 However, sea salt, which is usually minimally processed, has some amounts of calcium, magnesium and potassium.81

Q: Is iodine poisonous?

A: Iodine can be poisonous and can have dangerous side effects if you take too much of it.82,83,84Before taking iodine supplements or significantly increasing your intake of iodine-rich foods, talk to a doctor to know about the amounts your body may need to prevent adverse effects.

Q: How much iodine do I need?

A: According to the National Institutes of Health’s Office of Dietary Supplements, the amount of iodine that you need typically depends on your age. The upper limits for an adult are 1,100 micrograms.85

Sources and References:

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