Iodine—The Most Misunderstood Micronutrient

Friday Aug 8 | BY |
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Earth’s oceans are the main repositories of iodine,
and nowhere is iodine as highly concentrated as in seaweed.

Have you ever wondered what nutrient you’re lacking most? Is it vitamin D3, B12, folic acid, or iron?

These nutrients are among those that get a lot of media coverage and clinical attention. Even vitamin K2 is getting more press. But, iodine—the most misunderstood nutrient—needs more attention, and rightfully so.

The Amazing Iodine Molecule

Iodine is one of the most beautiful of all elements. When solid, it is a heavy gray metallic material. When heated, it does not melt. Instead, it sublimes. Sublimation is the process by which a solid turns directly to a gas without first melting. When iodine sublimes, its vapor gives off a violet glow.

Iodine Deficiency

The consequences of iodine deficiency are well known by scientists. Yet despite this knowledge, rates of iodine deficiency have reached epidemic levels, increasing fourfold over the past 40 years. A startling 74% of normal, “healthy” adults do not get enough iodine. So why don’t doctors know more about the effects of not enough iodine? Let’s take a closer look.

Iodine is critical to healthy thyroid function. The thyroid hormones—triiodothyronine (T3) and thyroxine (T4)—are tyrosine-based hormones produced by the thyroid gland that are necessary for healthy metabolism. Iodine is a key component in the production of T3 and T4. Not enough iodine causes reduced production of T3 and T4, which results in an enlarged thyroid gland.

Iodine deficiency can cause weight gain, low energy, depression, and is associated with cardiovascular disease, cognitive decline, and with a variety of cancers—all health risks that are also associated with low thyroid hormone.

When iodine deficiency is severe, it causes goiter and cretinism, mental retardation, infertility, and increased perinatal death. Iodine deficiency is a significant global public health problem. Even borderline low levels undermine your personal wellness.

What Happened To Our Iodine Supply?

There are two main reasons why iodine deficiency is making a comeback: (1) lack of iodine in the food chain, and (2) interference by toxic chemicals.

Until recently, about 25% of the iodine in the diet was from wheat, because iodine was used in the processing of flour. But now, a lot of flour in the U.S. is processed with a chemical cousin of iodine, bromide (potassium bromate), which helps makes flour doughier, rise higher, and gives the loaf a better appearance. Bromide has its own problems, though. Not only has it replaced iodine in bread, which is an important source of energy from starch in the American diet, but it can block the activity of iodine.

Sources of Bromine:

  • Baked goods
  • Citrus flavored soft drinks
  • Fabric fire retardants
  • Hair dyes
  • Prescription medicines
  • Pesticides used on strawberries
  • Plastics
  • Toothpaste and mouthwashes

This is also true for two more of iodine’s chemical cousins: chlorine and fluoride, both of which are found in tap water. Fluoride is by far the worst iodine disrupter. It’s found in commercial toothpaste and in most of our public water supply, so every time you take a shower, brush your teeth, or drink from the tap, the body gets a little fluoride. Eventually, it builds up and over time leeches out iodine.

If you are on a wheat-free diet and don’t drink tap water, you can avoid bromide, chlorine, and fluoride, but you may not get enough iodine unless you eat seaweed or take iodine supplements. All seaweeds are excellent natural sources of iodine.

Women’s Health and Iodine Deficiency

Women need more iodine during pregnancy and while nursing, due to increased thyroid hormone production, increased iodine loss in urine, and higher fetal iodine requirements. Adverse effects of iodine deficiency in pregnancy include enlarged thyroid in the mother and fetus, and in the infant it can cause cretinism, intellectual impairments, and low thyroid activity in the newborn. Dietary iodine requirements are also higher when nursing due to the concentration of iodine in breast milk.

Breast health also requires sufficient iodine. The link between breast cancer and thyroid disease reveals that there is an increased prevalence of autoimmune thyroid disease like Hashimoto’s in patients with breast cancer.

One area in which thyroid and breast functions overlap is in the uptake and utilization of dietary iodide. Researchers found that iodine supplements or iodine-rich seaweed inhibits breast tumor development. This is not surprising because Japanese women, who consume a diet containing iodine-rich seaweed, have much lower incidence of breast cancer than American women.

Iodine Synergy

Scientist and doctors know that thyroid hormone metabolism depends on getting enough iodine. What’s not on your doctor’s clinical radar is that iodine deficiency may produce conditions of oxidative stress creating toxicity in the cells. Healing cytotoxic effects depends on enough antioxidant enzymes and correcting selenium deficiency, one of the most important dietary antioxidants. For iodine to work best, you need enough selenium.

How Much Iodine Do You Need?

The recommended dietary allowance of iodine is 100 micrograms/day for adults and adolescents, 60-100 micrograms/day for children aged 1 to 10 years, and 35-40 micrograms/day in infants aged less than 1 year. Is that recommended enough?

Common Sources of Dietary Iodine:

  • Dairy Products
  • Eggs
  • Iodine-containing multivitamins
  • Iodized table salt
  • Saltwater fish
  • Seaweed (including kelp, dulce, nori)
  • Shellfish
  • Soy products

Low iodine might also contribute to chronic fatigue syndrome (CFS) and fibromyalgia, both associated with low thyroid function. One study showed that people with low body temperature and fatigue felt better and had more energy when they took a daily supplement of 1,500 micrograms of iodine, 15 times the RDA.

Most integrative medicine physicians agree that it’s reasonable for those with hypothyroidism, CFS, or fibromyalgia to take more iodine. The standard recommendation starts with between 6-12 mg (6,000 – 12,000 mcg) of iodine daily for three months to see if it helps. If iodine deficiency is the source of the problem, you’ll feel an increase in energy within the first month. But these initial high levels are too much, and over time may become toxic levels.

Symptoms and Conditions Associated with Low Iodine:

  • Breast cysts or tenderness, or breast cancer
  • Chronic fatigue syndrome
  • Fibromyalgia
  • Thyroid disease or thyroid cancer
  • Low body temperature under 98 degrees Fahrenheit
High Potency Iodine/Potassium Iodide Supplements

Iodoral® is a tablet form of Lugol solution available in two strengths: 12.5mg and 50mg. One 12.5 mg. tablet of Iodoral supplies a level of elemental iodine that is comparable to the average daily intake of Japanese, a population with a very low prevalence of fibrocystic disease of the breast and breast cancer.

To avoid the risk of excess body burden of too much iodine, which occurs even among Japanese, such high dosages are considered orthomolecular and should only be administered by a physician knowledgeable in iodine supplementation.

Best Source of Iodine—The Sea

Earth’s oceans are the main repositories of iodine, and nowhere is iodine as highly concentrated as in seaweed. Seaweeds such as kelp and bladderwrack can concentrate and store iodine at astonishing levels. Scientists speculate that these primitive plants accumulate iodine to protect themselves from oxidative stress in the open ocean. When consuming seaweed regularly, humans reap the benefits of this natural process, because the iodine in these seaweeds is in the most biologically available forms. For iodine health, I recommend regular addition of small amounts of edible seaweed in the daily diet.

How Do You Know If You Need More?

Until recently, there are no readily available and accurate tests, so iodine deficiency wasn’t diagnosed in individuals. Most doctors still don’t routinely test for iodine. However, since iodine is released form the body in urine, the best way to determine iodine deficiency is to measure the amount of iodine in urine samples. Iodine deficiency is defined as a median urinary iodine concentration less than 50 ?g/L.

Iodine is now also easily measured in a blood test. The laboratory reference range is 40.0-92.0 ?g/L. Iodine deficiency is below 40, but clinically those with less than 50 require iodine supplements.

Can You Take Too Much?

Like all trace minerals, too little causes health problems, but too much is toxic. Acute iodine poisoning is rare and usually occurs only with doses of many grams. Symptoms of acute iodine poisoning include burning of the mouth, throat, and stomach; fever; nausea; vomiting; diarrhea; a weak pulse; and coma. If you experience any of these symptoms, reduce your dosage of iodine, and if symptoms persist discuss your concerns with your doctor.

Symptoms Caused by Iodine Excess:

  • Acne
  • Stomach pain
  • Burning mouth and tongue
  • Fever
  • Nausea
  • Vomiting
  • Diarrhea
A Note on Radiation-Induced Thyroid Cancer

Radioactive iodine is released into the environment as a result of nuclear reactor accidents. Thyroid accumulation of radioactive iodine increases the risk of developing thyroid cancer, especially in children. The increased iodine trapping activity of the thyroid gland in iodine deficiency results in increased thyroid accumulation of radioactive iodine. Thus, iodine-deficient individuals are at increased risk of developing radiation-induced thyroid cancer because they will accumulate greater amounts of radioactive iodine.

Potassium iodide administered in pharmacologic doses of 50-100 mg for adults within 48 hours before or eight hours after radiation exposure from a nuclear reactor accident can significantly reduce thyroid uptake radioactive iodine and decrease the risk of radiation-induced thyroid cancer.

Dr. J. E. Williams


Dr. Williams is a pioneer in integrative and functional medicine, the author of six books, and a practicing clinician with over 100,000 patient visits. His areas of interest include longevity and viral immunity. Formerly from San Diego, he now resides in Sarasota, Florida and practices at the Florida Integrative Medical Center. He teaches at NOVA Southeastern University and Emperor’s College of Oriental Medicine.

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  1. June Hanson says:

    Sure glad, you take care of my thyroid. It is complicated. I do have low body temperature, when I kept tract of temperature, in a.m. before arising. Very rare to be a normal 98.6. so, according to you, I need seaweed. No wonder, I love to be in salt water! With you, I was, (emphasis on was) always in hot water. Things have changed, aren’t you glad, my dear doctor? So, You are going to have to show and tell me how on earth to prepare seaweed!! You,ve helped me with my fibromyalgia, surgeries, infections, angina, pains, even being stiff-necked, that one took a miracle worker!! Do I, have confidence in you, you’d, better believe it. My life, is in your hands. I feel, very safe and secure, with you. That, must work, with, both of us. It is called, trust, which. gets results, that lasts.

  2. I am having problems loosing the last few pounds to get to my desired target weight. I had my doctor check my thyroid function and my iodine level was low. I do not eat table salt and stopped eatting seaweed due to concerns about contamination. Where can I get seaweed that is not contaminated? How much seaweed should I eat daily?

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