Iodine

What is Iodine?

Iodine is a halogen or halide and an essential trace mineral required in small amounts for various important functions around the body. Other halogens include fluorine, bromine and chlorine, among others.

Iodine was discovered by English chemist Sir Humphrey Davy. The word iodine is derived from the Greek word ‘ioeides’ which refers to ‘violet-colored’. The suffix ‘ine’ was added by Davy in its connection to chlorine and fluorine.

Iodine is mostly needed by the thyroid and is essential for the synthesis thyroid hormones. Iodine is also used by the ovaries and breasts.

Iodate (IO₃⁻) is the bioavailable form of iodine found in food. Iodide form of iodine is rapidly absorbed in the stomach and small intestines with 100% the iodide being absorbed.

The thyroid gland contains the highest concentration of iodine with around 80 to 90%. Iodine blood concentration is controlled by the thyroid gland. The only sole function of iodine in the body is the synthesis of Thyroxine (T4) and Triiodothyronine (T3). T4 is the inactive form and T3 is the active form of thyroid hormone. Around 15 to 20mg of iodine is stored in the body which means a daily intake of adequate amounts is needed.

Health benefits of Iodine

Supports thyroid health

Iodine is vital for thyroid health and a deficiency can lead to various thyroid disorders. Iodine can be found concentrated in the thyroid glands and helps the body produce thyroid hormones. Iodine along with selenium plays a very important role in the thyroid by supporting and maintaining its functions in the body. There are many interactions between selenium and iodine associated with thyroid health. Iodine is found concentrated mostly in the thyroid glands.

A deficiency of iodine can cause thyroid conditions such as the development of goiter, cretinism, hashimotos, Graves disease, hypothyroidism and hyperthyroidism.

Goiter manifests as an enlargement of the thyroid gland, this enlargement occurs due to low levels of iodine which the thyroid gland compensates for in order to produce thyroid hormones.

Deiodinase enzymes (DI’s) which rely on selenium are involved in the conversion of the thyroid prohormone T4 (thyroxin) into the active hormone T3 (triiodothyronine). These important enzymes also help convert T3 into T2. The activation of T3 by Deiodinase enzymes occur in the liver and brain.

If iodine is deficient the body’s production of deiodinase Type I enzyme (DI-I) is increased and has been shown to increase in cattle by 10-12 times. The extra increase focuses on converting existing T4 to the active T3 and then further to T2 which is the degraded by-product of T3. In an iodine deficient state there is too little T4 which also decreases the active T3 leading to thyroid health disorders such as hypothyroidism.

If selenium is also significantly low this can reduce iodine levels and can cause severe thyroid conditions as both nutrients are vital to thyroid health in the correct balance.

Studies dating back to 1917 through 1922 by Dr. David Marine has successfully shown iodine to reduce symptoms of goiter. This was shown in one study on 2000 schoolgirls given an 18.6 mg dose of iodine for 2 ½ years. It was due to this study was iodization of salt was introduced in the US. However iodization of salt is not mandatory and currently not all salt on the market is iodized salt.

Some studies are also showing that iodine can decrease insulin requirements for those with diabetes mellitus (type 2). One study has shown a connection between lowering effects of iodine in those with type 2 diabetes. Thyroid dysfunction has also been linked to diabetes. [1] [2] [3] [4] [5] [6] [7] [8]

Supports brain development and increases IQ

Iodine is needed for brain development and proper cognitive functions. Multiple studies have shown that IQ is linked to iodine levels. [9]

Support breast health and prevents formation of lumps, cysts and tumors

Iodine is needed by the breasts and can help shrink fibroadenomas, fibroids, tumors, cysts and lumps. In various countries including Japan the consumption of seaweed and seafood have a lower prevalence of breast disease and breast cancer.

Iodine is involved in apoptosis which is the process of programmed cell death needed to remove cancerous or diseased cells. Iodine deficiency has been linked to fibrocystic breast disease where a supplementation of iodine has shown to reduce symptoms.

Iodine helps to balance estrogen levels through a process known as cell differentiation. Keeping estrogen levels balanced can help prevent breast cancer which may be caused by excess estrogen.

Some studies have also shown iodine supplementation can reverse fibrocystic breast disease.

A study in 2003 showed iodide reduced lung cancer tumors in mice. [10] [11]

Prevents cancer

Iodine deficiency has been linked to various forms of cancer such as breast cancer and thyroid cancer. It can help protect against Helicobacter pylori which has been linked to gastric cancer.

Iodine has antibacterial qualities that can protect against bacterial infections. Iodine has shown to protect against bacterial infections such as Helicobacter pylori in the stomach. Iodine does this through its role in apoptosis, programmed cell death which removes cancerous and diseased cells. [12][https://www.ncbi.nlm.nih.gov/pubmed/27337594]

Essential for energy and metabolism

Iodine helps the thyroid glands to regulate metabolic rate through hormone production. This is essential for the proper functions of all organs. A healthy metabolism and metabolic rate is vital to the health of the body as it determines how food is converted into energy to provide fuel for basic functions of the body. Iodine is involved with the synthesis of thyroxine and triiodothyronine which affect various bodily responses such as weight, temperature, heart rate and blood pressure.

Maintains healthy skin and hair

Iodine’s important role in metabolism means many nutrients are properly absorbed. Many nutrients are associated with healthy skin and hair. Iodine deficiency is associated with dry, flaky skin and hair loss.

Supports a healthy pregnancy

Iodine is needed for the healthy development and growth of the baby. Having sufficient iodine is important for pregnant women as a deficiency of this nutrient can lead to stillbirths or cretinism in newborn babies. Iodine is passed onto the baby through breast milk and if the mother is deficient this will negatively impact the development of the child. Iodine in nursing mothers and pregnant women can be rapidly depleted increasing the requirement for more iodine. [13]

Helps with detoxification

Having sufficient iodine and other nutrients such as selenium can help remove excess of other harmful heavy metals such as lead and mercury. It can also help prevent excessive build-up of fluoride, bromide, bromine and chlorine in the body. Iodine has similar properties and needed alongside selenium with both nutrients helping to reduce free radicals. [14]

Supports protein synthesis

A sufficient supply and functioning thyroid hormones is essential in the synthesis of protein. Without iodine the process of protein synthesis can affect the development and maintaining health and wellbeing.

Iodine has antibacterial, antiviral and antifungal properties

Iodine has can help prevent infections from pathogens, bacteria, viruses, parasites, molds, fungi and malaria. Iodine may help address the issues of antibiotic resistant superbugs. Iodine is one of the many natural antibiotic solution available which help treat a number of infections. Iodine has been used for the treatment of tuberculosis in the early 90s.

Boosts immune system

Many health problems and disease are associated with inflammation which can be improved by iodine. Iodine plays a role in transporting granulocytes in the location of inflammation around the body and aids in destroying harmful bacteria.

Agonist / Synergist

Vitamins: A

Minerals: Selenium

Retinoic acid promotes iodine uptake. [15]

Vitamin A improves iodine efficacy suggesting a synergy between these two nutrients. [16]

Vitamin A deficiency decreases iodine uptake which interferes with thyroid metabolism [17]

Both iodine deficiency and vitamin A deficiency can cause severe primary hypothyroidism than iodine deficiency alone. [18]

Iodine and selenium work synergistically for thyroid hormone metabolism. Selenium is a cofactor for enzymes that help convert T4 to T3. [19]

Antagonists

Minerals: Flouride

Halogens: flourine, chlorine, bromine

Heavy metals: Mercury

Other: Smoking, stress, high estrogen, poor diet, low salt intake (iodized salt), goitrogens

The halogens fluorine, chlorine, bromine and iodine compete with each other for absorption. The halogens that have an antagonistic effect on iodine all exist in the environment and when dietary intake of iodine is low this causes a deficiency. Bromine can be found in many common household products.

Goitrogens are compounds which can inhibit the absorption of iodine in the thyroids. These foods include cruciferous vegetables, millet, cassava and soy. Goitrogen compounds in these foods can be eliminated or reduced through cooking.

Food sources of Iodine

Iodine can be found in sea kelp or seaweed, yogurt, iodized salt, cod, shrimp, tuna, dried prunes, cheddar cheese and eggs. In some countries white bread is fortified with iodine.

Cruciferous vegetables such as broccoli, cabbage contain iodine however they also contain goitrogens which can inhibit iodine absorption. Goitrogen compounds can be eliminated by cooking these vegetables.

Recommended Dietary Allowance

Age	Iodine: Adequate Intake (AI) in micrograms (mcg/d)
INFANTS
0-6 months	110 mcg
7-12 months	130 mcg

Age	Iodine: Recommended Dietary Allowance (RDA) in micrograms (mcg/d)
CHILDREN
1-3 years	90 mcg
4-8 years	90 mcg

Age		Iodine: Recommended Dietary Allowance (RDA) in micrograms (mcg/d)
MALES
9-13 years	120 mcg
14-18 years	150 mcg
19-30 years	150 mcg
31-50 years	150 mcg
51+ years	150 mcg

FEMALES
			Pregnancy	Lactation
9-13 years	120 mcg
14-18 years	150 mcg		220 mcg	290 mcg
19-30 years	150 mcg		220 mcg	290 mcg
31-50 years	150 mcg		220 mcg	290 mcg
51+ years	150 mcg

Tolerable Upper Intake Level (UL) for iodine is set at or 1000 mcg for healthy adults. [20] [21]

Iodine Supplementation

Iodine is available in various forms which can be found as liquid, capsules and tablets. Capsules nad tablet forms of iodine can be found in kelp supplements. Liquid forms of iodine include nascent iodine and Lugol’s iodine. It is also found as iodide as potassium iodide or sodium iodide. Iodine can also be found in multivitamins.

Nascent iodine is a highly potent form of iodine and lower doses are needed than Lugol’s iodine. Lugol’s iodine is a formula created by a French doctor, Jean Lugol in 1829 by mixing iodine with potassium iodide in water. The various organs, cells and tissue such as the breasts, prostate, thyroid utilize iodine however the kidneys, liver, spleen and blood can utilize both iodide and iodine.

Lugol’s iodine has a strong taste which may not be tolerable for many individuals and may cause gastric upset. Iodine painting is utilized for transdermal absorption however this method may mean a lower absorption. The taste is better tolerate with nascent form. Nascent iodine is expensive with Lugol’s iodine to be comparatively cheaper. Iodoral is the tablet form of Lugol’s iodine however may not be as readily available. [22]

In 1997 a study known as Iodine Project by Dr. Guy Abraham, Dr. David Brownstein, and Dr. Jorge Flechas which was followed over a number of years has shown positive results of administering 12.5 to 100 mg daily of iodine. Some of the results included a reversal of fibrocystic breast disease, decreased need for insulin in diabetics, less requirement for medications needed by patients with hypothyroidism, resolved fibromyalgia, reduced migraines and headaches. This has led into what is known as the Iodine Protocol, which is a therapy for restoring iodine levels with the use of companion nutrients such as ATP co factors B2, B3 in addition to magnesium and selenium.

Deficiency symptoms of Iodine

The following are iodine deficiency symptoms:

Fatigue / Tiredness
Low energy
Lethargy
Brain fog
Muscle weakness
Joint stiffness
Weakness
Slowness of movement
Delayed reflexes
Dry skin
Coarse skin
Sensitivity to cold
Cold hands and feet
Changes in Heart Rate
Shortness of breath
High cholesterol (Hyperlipidemia)
Recurrent infections
Impaired kidney function
Depression
Intellectual disability
Poor perception levels
Trouble Learning and Remembering
Low IQ
Thyroid issues
Goiter*
Swelling in neck (swollen thyroid gland)
Constipation
Weight gain (abnormal)
Heavy periods
Decreased fertility
Pregnancy complications
Increased risk of stillbirth
Endometriosis
Fibroids
Fibroadenomas
Fibrocystic breasts
Tumors
Hair loss
Thinning hair

*Excessively high and low iodine can lead to the development of Goiter and many other thyroid conditions.

The following are health disorders associated with iodine deficiency:

Cretinism
Goiter
Hypothyroidism (inadequate production of thyroid hormones)
Fibrocystic breast disease (FBD)
Breast cancer
Atherosclerosis
Hyperlipidemia
Kashin beck disease

Causes of iodine deficiency include

Inadequate intake through diet
Pregnancy (during pregnancy iodine requirement increases)
Exposure to halogens chlorine, bromine, fluorine or fluoride
Selenium deficiency
Iodine deficient soil
Smoking

Iodine deficiency is also associated with infant mortality. Having sufficient levels of iodine is important for pregnant women as a deficiency has been linked with cretinism and can impact the development of the fetus. Defiency in children can be seen with signs such as poor cognition and intellectual disability.

Iodine deficiency can cause the development of thyroid nodules in the thyroid gland which increases the risk of cancer if the nodules increase in size.

Exposure to chlorine, bromine and fluorine can lead to a deficiency as all these halogens compete with each other as well as with iodine. There are many sources of these iodine atagonists from bromine in flame retardents which can be found in many household products such as sofas and mattresses. Flouride and chlorine can be found in tap water and other sources.

Iodine deficiency has been linked to many thyroid disorders. Hypothyroidism is a thyroid disorder associated with iodine deficiency where the production of thyroid hormones is reduced by the thyroid gland. An iodine deficiency can also occur when selenium is also low as both these nutrients work synergistically in assisting thyroid function. [23] [24] [25]

Deficiency of iodine can lead to an increased output of thyroid stimulating hormone (TSH). The increase of TSH causes the thyroid to compensate for the lack of iodine by taking from the blood to restore levels in the thyroid gland which begins to occur when iodine levels fall below 100 mcg per day.

Deficiency occurs when iodine levels drop between 10 to 20 mcg per day which reduces intake in the thyroid. Eventually this can cause various symptoms of thyroid conditions such as the development of goiter and hypothyroidism.

Iodine and selenium work synergistically and both are needed for the functions of the thyroid gland. If either one of these nutrients become deficient it can lead to various health conditions related to the thyroid gland. The interactions between selenium and iodine are more evident when either one becomes deficient.

Both selenium and iodine can lead to the thyroid disorder Goiter where the thyroid gland increases in size as a mechanism to promote hormone synthesis to compensate for the reduced amounts of iodine. A deficiency of both nutrients can further enlarge the thyroid gland with a larger Goiter. [26]

In some parts of Africa the percentage of population with goiter is high along with the prevalence of many other thyroid health conditions and linked to both iodine and selenium deficiency. [27] [28]

Some studies have shown that supplementing with selenium can make hypothyroidism condition worse when iodine is also deficient. Other studies are also showing that iodine supplementation without selenium can also damage thyroid gland. This suggests that if both selenium and iodine are deficient then intake of both will be needed.

Those with certain thyroid conditions such as Hashimoto's thyroiditis are often advised not to take iodine as it has shown to worsen the condition. However those with Hashimoto’s thyroiditis have also been shown to have a selenium deficiency which implies that the worsening of symptoms when supplementing with iodine are more likely due to insufficient selenium levels. [29]

Iodine intake increases the production of H202 which in higher amounts can damage the cells of the thyroid, this may be counteracted by selenium’s role in protecting against oxidative damage. Selenium is an important part of glutathione peroxidase (GPX / GSHPx) which is an antioxidant complex or enzyme that helps to prevent oxidative damage (reduce peroxides) and stabilize cell membranes.

Studies are showing that concurrent iodine and selenium deficiencies can prevent hypothyroidism symptoms from becoming worse by maintaining levels of T4 whereas a deficiency of either one or an imbalance of these two nutrients lowers T4 levels. Keeping selenium and iodine at a similar level seems to prevent a further reduction of T4. Many thyroid conditions also seem to be linked to either iodine being too high with low selenium or vice versa which means that both are required in sufficient amounts and balanced.

Statistics of thyroid disorders suggest that many people may be deficient in iodine despite access to iodized salt. In addition exposure to other halides that compete with iodine has been increasing and can be found virtually everywhere in the environment.

Toxicity symptoms of Iodine

Iodine toxicity is rare but can occur from high intake in supplemental form. Some symptoms associated with iodine toxicity are similar to iodine deficiency. Signs and symptoms of iodine toxicity include:

Goiter* (enlarged thyroid gland)
Thyroid gland inflammation
Cancer (thyroid papillary)
Thyroid dysfunction
Thyroiditis
Burning of the mouth, throat, and stomach (mucosa)
Fever
Abdominal pain
Nausea
Vomiting
Diarrhea
Weak pulse
Cyanosis
Coma
Increased requirement for selenium

Precautions and warnings

Supplements can interact with certain medications, treatments and health conditions which is why it is important to speak to a doctor before taking iodine supplements.