Iodine in a nutshell
Iodine is essential in the production of the thyroid hormones T3 and T4. A deficiency of iodine can cause Functional Hypothyroidism or goiter, Too much iodine can result in Hyperthyroidism.
Best source of Iodine for Juicers
Iodine is found in pineapple, lettuce, spinach and green peppers.
Alternative names: Iodine. Our bodies absorb iodine in the form of iodides, most commonly sodium iodide.
In 1998 a tiny Albanian town called Propisht sent out an urgent call for help. Every town has a few children who are developmentally delayed, but in Propisht, every child was developmentally delayed.
One of the first officials to arrive in the town was a child psychologist. He gave the children an eye-hand coordination test involving putting beads on a string. Not a single child in the town could complete it. Worse, many of the children were simply not growing any taller or heavier after the age of 10.
The problem, it was later discovered, originated in the school cafeteria. The schools had instituted an all you can eat soup bar. All the children filled up on cabbage soup. A little cabbage soup is not a bad thing, but eating huge bowls of cabbage soup every day can flood the body with sulfur-containing goitrogens. These are compounds that stop the thyroid from absorbing the iodine it needs to make thryoid hormone.
The remedy for the catastrophe in the Albanian town was as simple as telling the children “no more soup for you.” Along with iodine supplements, the simple change of diet stopped the plague of developmental delays for nearly every child in town, and prevented a generation of suffering.
What Is Iodine?
Iodine in its elemental form is a gas that almost instantly combines with the oxygen in the atmosphere to form solid iodine compounds. Various compounds of iodine accumulate in rocks and are released as the rocks weather into soil.
Iodine is famous as the essential element for the production of thyroid hormone, but since plants don't have thyroids, why should they absorb iodine? It turns out that iodine is useful for plant life but not essential for plants in the ways that it is for humans. In plants, iodine can transform fatty acids into a form that is less likely to be attacked by heat and light. This increases the survival of the plant and its seeds, but iodine is not essential for the life of the plant in the same way that it is essential for life in animals and human beings. Until the twentieth century, animals and people who lived in certain locations did not get enough iodine in plant foods to prevent disease.
What Does Iodine Do in the Human Body?
Iodine also helps transform certain kinds of saturated fats into unsaturated fats in humans. Its far more fundamental role in human health, however, is as the essential component of the two forms of thyroid hormone, T3 and T4.
The thyroid gland is a butterfly-shaped gland in the front of the neck, just below the Adam's apple. A healthy thyroid gland is about the size of a walnut, about 8 to 10 mm across. The thyroid hormone it produces is critical for every cell in the human body.
If you were to compare the basal metabolism of the human body to a car, you could liken the thyroid gland to the accelerator. Thyroid hormone travels through the bloodstream and attaches to each cell. When this hormone is present, a protein called thyroid hormone receptor binds to DNA.
Activating DNA in this way gives the cell “permission” to respond to growth hormones and stress hormones. DNA activation enables the cell to use proteins, carbohydrates, and fats. Thyroid hormone stimulates cells to generate heat to keep the body warm.
The more of the active, T3 form of thyroid hormone the thyroid releases into the bloodstream, the faster these processes occur. The less active thyroid hormone released into the bloodstream, the slower these processes occur. But making thyroid hormone is impossible without iodine.
What Happens When We Don't Get Enough Iodine?
If you live in North America, it's really rare to suffer an iodine deficiency. In the USA and Canada, iodine is added to salt. Most Americans and Canadians actually get 8 to 10 times more iodine than their bodies can use. Most people in Scandinavia and Japan also get very large amounts of iodine in their diets due to high consumption of fish.
In the rest of the world, however, iodine deficiency is quite common. Up to 72% of people who live in Africa have iodine deficiencies causing thyroid problems. Up to 70% of people in the United Kingdom also have deficiencies in iodine.
But it isn't just iodine that is needed for thyroid health.
In the first step of the production of thyroid hormone, the thyroid combines four atoms of iodine to one molecule of an amino acid known as tyrosine to make one molecule of levothyroxine, also known as T4.
T4 is the form of thyroid hormone the thyroid stores for long-term use. Most of the time, about 99% of the body's total supply of thyroid hormone is in the form of T4. This kind of thyroid hormone cannot flow through the bloodstream unless it is attached to a specialized carrier protein.
The form of thyroid hormone that actually stimulates the metabolism is triiodothyroine, which is also known as thyronine or T3. The thyroid makes T3 by stripping one iodine atom off T4. It's actually T3 that stimulates energy production and activates cells to respond to hormones all over the body. T4 is the form of thyroid hormone that doctors measure but T3 is the form of thyroid hormone that really makes a difference.
The thyroid can't make T4 without iodine. But it can't make T3 without selenium, zinc, and vitamin C. And you need magnesium to balance selenium and copper to balance zinc. It isn't enough to get iodine without also getting selenium, zinc, vitamin C, magnesium, and copper, along with the tyrosine the thyroid needs for making T4.
What happens when your body can't produce enough T3? People who have functional hypothyroidism may experience any or all of the following symptoms that may come and go.
- Loss of energy, chronic fatigue
- Weight gain
- Decreased appetite
- Sensitivity to cold
- Blurred vision
- Decreased hearing
- Decreased perspiration
- Dry skin
- Forgetfulness, impaired memory, inability to concentrate
- Fullness in the throat, hoarseness
- Menstrual disturbances, impaired fertility
- Mood swings or mental impairment
- Muscle pain, joint pain, weakness in the extremities
- Partial paralysis and nerve entrapment syndromes
- Patchy hair loss
Most people who develop hypothyroidism do not, however, develop a condition known as goiter, which is described below.
Are You at Risk for Iodine Deficiency?
Iodine deficiency sometimes actually is just a matter of not getting enough iodine in the diet. In the Middle East, South Asia, and Africa, the symptoms of hypothyroidism are likely to be due to simple iodine deficiency. Taking an iodine supplement and making sure to get enough tyrosine (an amino acid that is abundant in fermented protein foods such as fermented fish or cheese) treats the problem.
In much of Europe, however, iodine deficiency isn't caused by consuming too little iodine but rather by consuming too many goitrogens. This was the problem for the school children in the Albanian town of Propisht.
A goitrogen is a food substance that blocks the thyroid's ability to absorb iodine. When the thryoid's iodine receptor sites are blocked by goitrogens, it behaves as if the diet were deficient in iodine, even though it is not.
Cabbage and other vegetables in the cabbage family contain sulfur-bearing goitrogens known as isothiocyanates. These are the same compounds that fight cancer (although their ability to fight cancer depends on whether the individual eating the vegetable has a gene that responds to the compound). Isothiocyanates are abundant in cabbage, cauliflower, kale, collards, kohlrabi, bok choi, broccoli, Brussels sprouts, rutabagas, turnips, and watercress. Isothiocyanates are most abundant when these vegetables are served raw or steamed, although they are broken down if the vegetable is boiled, microwaved, or used in a stir fry.
Three starchy foods that are often eaten in tropical South America also release goitrogens. Even properly prepared manioc root (the source of tapioca), agave, and yuca release natural cyanides in the stomach. (Improperly prepared manioc root can release fatal amounts of cyanides into the stomach.) These cyanides become isothiocyanates in the small intestine and then interfere with iodine absorption in the same way as the isothiocyanates from vegetables in the cabbage family. During famine, however, these foods slow down the metabolism enough that people who eat them are less likely to starve—but they are very likely to suffer other symptoms of hypothyroidism.
Goitrogens are not the only plant compounds that can interfere with iodine absorption. Soy products contain two isoflavones, daidzein and genistein, that cause the liver to take T4 out of the bloodstream and excrete it into the gallbladder where it is send to the small intestine for elimination from the body. Most adults begin to lose iodine if their daily consumption of soy products exceeds:
- 4 oz or 112 grams of tofu eaten as the only soy food of the day, or
- 8 oz or 240 ml of soy milk eaten as the only soy food of the day, or
- 2 tsp or 10 grams of miso eaten as the only soy food of the day.
These amounts of soy foods are enough to provide all the soy isoflavones the body can use for bone health and hormonal regulation, however. Almonds, pecans, and walnuts contain similar compounds that can cause problems when they are eaten in large quantities (more than 8 oz/224 grams per day).
Even the antioxidant anthocyanidins found in blueberries, blackberries, raspberries, and strawberries can interfere with your thyroid's ability to absorb iodine, if you eat more than 1 cup/100 grams per day. Strawberries grown in the USA present an additional problem for people at risk of thyroid deficiency because they are treated with bromides. Bromides sprayed on strawberries and bromides used to keep flour and sugar from forming clumps can also compete with iodine for absorption into the thyroid.
Eating these otherwise healthy foods can put you at risk for iodine deficiency. Too much iodine, however, can be as detrimental as too little.
The Problem with Too Much Iodine
In both Japan and the United States, many people develop hypothyroidism as a consequence known as Hashimoto's thyroiditis, which is also known as hyperthyroidism. When there is too much iodine in the diet, more than about 1,000 mg a day, the thyroid can become hyperactive, producing too much thyroid hormone. For a few months to a few years, the overproduction of thyroid hormone can cause a variety of symptoms including:
- Exophthalmia, or enlargement of the eyeballs
- Feeling of fullness in the throat
- Low-grade fever
- Neck pain, sore throat, or both
- Painless thyroid enlargement
Like people with hypothyroidism, people who have hyperthyroidism may experience any or all of these symptoms and symptoms may come and go. In most people who have hyperthyroidism, however, the immune system eventually attacks the thyroid as overactive, “foreign” tissue. The symptoms of hyperthyroidism cease and the symptoms of hypothyroidism begin.
Many people start taking iodine supplements in order to stimulate the production of thyroid hormone, and it works. However, the immune system then attacks the thyroid even more strongly and makes hypothyroidism permanent. Correcting thyroid problems can't be done with iodine alone.
What Should You Do If You Think You Have a Thyroid Problem?
It's always better to test for an endocrine problem that it is to try to peer in to a crystal ball and guess your diagnosis. Doctors can measure thyroid stimulating hormone (TSH), T4, and T3 and tell you whether you have a true iodine deficiency or some other kind of thyroid problem, or perhaps both. The problem is that doctors typically just measure TSH and don't bother with the measurements of T4 and T3. Or they diagnosis hypothyroidism and begin thyroid hormone replacement therapy with a medication like Synthroid, which is pure T4. Your body still has to convert Synthroid into T3 for the medication to do any good. The natural alternative to Synthroid, Armour (spelled with a “u”) Thyroid, provides both T4 and T3, but most doctors won't prescribe it!
Dealing with doctors to get good thyroid care is beyond the scope of this article, but there are some very basic steps to good nutrition that can support your health whether you are diagnosed with hypothyroidism, hyperthyroidism, or you have borderline-low levels of thyroid hormone and just feel tired all the time.
1. Make sure you get enough iodine. That's just 100 mg per day, the amount of iodine in 1 teaspoon (5 grams) of iodized salt or a single 100 gram/3-1/2 oz serving of codfish, 1-1/2 servings of baked potato with the skin, 2 servings of dairy, 3 servings of poultry, or 3 servings of beans or lentils. A single strip of seaweed (enough to wrap three pieces of sushi) also provides a day's supply of iodine.
2. Make sure you don't get too much iodine. If you use iodized salt, that means not consuming more than about 5 teaspoons (25 grams) of salt per day. Don't eat too much dried fish or seaweed.
3. Even if you take thyroid replacement hormone, you still need at least 100 micrograms of selenium, 25 mg of zinc, 100 mg of vitamin C, 200 mg of magnesium, and 3 mg of copper per day to help your body make the enzyme that transforms T4 into T3.
4. Avoid overeating the foods that interfere with the thyroid's ability to absorb iodine. Most of these foods also contain phytate, which interferes with the body's ability to absorb minerals. Take your supplements between meals rather than with meals.
5. If you use iodine to support recovery from a health condition, don't use iodine supplements for more than one month at a time, one month on, one month off, to avoid Hashimoto's thyroiditis.
Using Iodine to Support Recovery from Fibrocystic Breast Pain
Four studies have found that taking large doses of iodine for 4 to 5 months reduces the severity of fibrocystic breast pain. Women in these studies have taken between 3 and 7 mg of iodine daily and usually get only partial relief from pain. Since the recommended upper limit of iodine consumption is just 1.1 mg per day, there is a real risk of developing Hashimoto's thyroiditis for women who take enough iodine to relieve breast pain.
Don't take this much iodine on a daily basis unless your doctor is monitoring you for the development of thyroiditis. There is a simple blood test for thyroid antibodies that can tell you when you need to stop iodine consumption in order to protect thyroid health.
Using Iodine for Radiation Protection
Every time there is news of some nuclear accident, both prices and sales of potassium iodide soar. Potassium iodide is of real use in case of mild radiation exposure. Taking a large dose of potassium iodide after an incident but before exposure to fallout floods the thyroid with so much non-radioactive iodine that it cannot absorb radioactive iodine. This reduces future risk of thyroid cancer.
Taking iodine after release of radiation, however, does not protect other parts of the body against the effects of radiation exposure. It offers no protection against gamma-radiation and it is not a remedy for radiation poisoning. While keeping potassium iodide on hand in case of a radiation event is a good idea, it should be only a very small part of your overall contingency plans for such an event. Never take more than one dose of iodine for radiation protection, and be forewarned that the 50 to 100 mg of iodine in most radiation protection kits will cause diarrhea and vomiting, especially in infants and children.