Iodine - The Forgotten Mineral

Iodine - The Forgotten Mineral

Iodine is one of the essential trace minerals of the body. It has a rich history commencing with its enigmatic discovery in approximately 2700BC. Historical records have shown that for many thousands of year Iodine food sources have been used in traditional Chinese medicine to treat Goitre (caused by both hypothyroidism and hyperthyroidism).

Unbeknownst to Chinese healers they were using Iodine as a therapeutic mineral much like we do today.
It was only in 1811 that scientist Bernard Courtois isolated the mysterious ingredient, he called it “Iodine”. Iodine is named as such because the it vapour it produces is violet/purple in colour and “iode” means violet in greek. In the 1900s it was realised that Iodine deficiency in the diet was linked with potential health problems. Then in the 1920s after much scientific research Iodine was finally associated with thyroid function.

Iodine deficiency is endemic to mountainous areas such as the Himalayas, Andes, Alps, and lowland regions in third world developing countries of Central Africa and Eastern Europe. The WHO found that 2 billion people suffer from Iodine deficiency in the world, and of that figure 20 million suffer from mental defects/retardation as a direct consequence [3].

Where is iodine found?

There are many natural sources of Iodine such as non-organic Cow’s Milk, Seaweeds (Kelp, Nori, Wakame and Dulse), Shellfish, Prawns, White Fish (Haddock), Cheese, and any vegetable, fruit or herb grown on, or animal grazed on Iodine rich soil [7].Unfortunately these sources tend to be poorly consumed. In majority of European countries it is mandatory to iodise salt, this was voluntarily undertaken by the USA. Iodising salt was a Unicef’s campaign, titled under their “MDG1: eradicate extreme poverty and hunger” mission[1]. Iodising salt is seen as an effective way to increase Iodine intake in these countries. This is not implemented in the UK because of government measures taken to reduce salt consumption.

There are two Iodine supplements available on the market. There is the artificially synthesised source, derived from Potassium Iodide and the most popular natural supplement for iodine which is Sea Kelp. It’s extracted from the leaves of the Luminaria Digitata. The Kelp plant grows long brown finger like strands that are flexible and move with the tide. The Luminaria Digitata is commonly found on the coasts of Wales, Scotland, Northern and Southern England[2]. These supplements are normally suggested for people that do not consume dairy, seafood or shellfish in their diets. The recommended dose is of 150mcg.

What is its biological uses in the body?

The primary use of Iodine in the body is for the generation of thyroid hormones Thyroxine (T4) and Triiodothyronine (T3), from the thyroid gland The thyroid gland is located in the neck and can be felt by running your fingers along the central region of the neck. It’s frequently described as a “Butterfly-Shaped” gland.

Iodine is absorbed as iodide through the gut wall and transported in the blood to the thyroid gland. The thyroid stores the Iodine as a substance called colloid. The iodide undergoes many complex steps including the enzymatic addition of tyrosyl, and the formation of intermediates that eventually go on to form thryroglobulin (Tg). Tg is the precursor for the hormones T3 and T4. T4 is de-iodinated to the active hormone T3 [3].

The function of the thyroid hormones include contribution to normal neurological/cognitive function and energy metabolism. There has also been profound evidence linking Iodine intake during pregnancy with the resultant IQ of the offspring. The study is generically known as the ALSPAC Study (Avon Longitudinal Study of Parents and Children), conducted by researchers, Sarah Bath, Colin Steer, Jean Golding, Pauline Emmett and Margaret Rayman (May,2013). The participants were selected upon the following criteria, ability to produce urine sample in the 1st trimester, single child pregnancy and their ability to conduct a follow up study when the child reached ages 8 and 9. There were 13,988 children who completed the study. The women took urine measurements in their first trimester and were allocated groups of either mild-moderate deficiency (<150,mg//g), or Adequate (>150mcg/g). Then a direct comparison of deficient and non-deficient mothers was undertaken on the effect it had on their IQ and reading age.

At 8 years of age when IQ (Intelligence Quotient) was measured it found reduced “cognitive outcomes” in the deficient mother’s offspring. IQ was measured at 105.1 points compared to the non-deficient mothers at 108.5. When reading age was measured at 9 years of age, the children of the deficient mothers showed “sub-optimal outcomes in Verbal IQ, reading accuracy and comprehension”[5].

What Deficiencies can occur?

In general the status of Dietary Iodine is poor, as mentioned previously it’s thought that 2 billion people in the world have an iodine deficiency.

A WHO (2004) statistic shows that 285 million school aged children in the UK were deficient in Iodine[3]. A 2011 study looked into the Iodine status of 14-15 year old School girls[6]. Over 700 girls were tested, of which mild deficiencies were present in 51%, moderate deficiencies in 16% and severe deficiency in 1%.

Table 1 demonstrates daily requirements of iodine needed: [4]


Iodine requirement per day (micrograms, ug/mcg)



Pregnant and breast feeding woman.


If the person’s Iodine intake is consistently low they will increase Iodine trapping, then overwork and exhaust their thyroid gland causing Goitre. Goitre is the most common known disease associated with the thyroid gland[4]. Other clinical signs of Iodine deficiency includes:

  • Foetal miscarriages, still birth, congenital abnormalities such as:
    • Neurological Cretinism, characterised by mental retardation, mutism and limb spasticity.
    • Myxodematous Cretinism, characterised by mental retardation, dwarfism, oedema, and hyperthyroidism.
  • Neonatal hyperthyroidism
  • Mental and physical retardation at all ages.

So what can you do to raise your iodine?

  1. Increase your intake of Iodine food sources. Try incorporating seafood, white fish, shellfish and seaweeds into your diet.
  2. Drink non-organic milk. In one 250ml glass of organic milk there is 30-55mcg, whereas non-organic milk has 50-80mcg.
  3. Buy Iodised salt. Cerebos is a trusted brand.
  4. If you are Vegetarian or Vegan, make sure you check your Iodine status regularly.
  5. Take Sea kelp tablets, or other Iodine based supplements, such as Potassium Iodide.
  6. Be aware of your Iodine status, if you think you may be deficient, get it checked.
  1. UNICEF. (2007).UNICEF- Progress for Children: A World Fit for Children, Statiscal Review. Available:
  2. Hill, J.M. (2008). Laminaria digitata Oarweed. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews, Plymouth: Marine Biological Association of the United Kingdom. Available from:
  3. Skeaff,S. Thomson,C. . (2012). 11.3-Iodine. In: Mann,J. Truswell,S.Essentials of Human Nutrition. 4th ed. Oxford: Oxford University Press. Pg. 177-184.
  4. Rayman,M, Professor. Bath,S Dr. (2013).Food Fact Sheet- Iodine. Available: file:///C:/Users/OV/Documents/Iodine%20Report/IodineFactSheetBDA20May2013.pdf.
  5. Bath,S. Steer,C. Golding,J. Emmett,P and Rayman,M. (2013). Eff ect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children: results from the Avon Longitudinal Study of Parents and Children (ALSPAC).Available: file:///C:/Users/OV/Documents/Iodine%20Report/BathIodineLancet22May2013.pdf
  6. Vanderpump,MP. Lazarus,JH. Smyth,PP. Laurberg,P. Holder,RL. Boelaert,K. Franklyn,JA.. (2011). Iodine status of UK schoolgirls: a cross-sectional survey, Lancet. 377 (9782), Pg.2007-2012
  7. DK-Kindersley,P. Lambert,L.Savage,A. Kindersley,D.. (2015). Foods That Heal , Other Foods. In: Steel,S. Neal's Yard Covent Garden Remedies, Healing Foods. London: Penguin Random House Company. Pg.131.
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