What is Iodine?

Iodine is a solid slate-gray crystalline nonmetal element belongs to halogen family in the periodic table Group VIIA. Iodine is naturally stable but highly reactive. Iodine exists as a monovalent anion in brines and in molecular compounds. Iodine exists in many different forms, ranging from colorless to many different colors depends on the iodine concentration in the solution like white, brown, yellow, red and blue. Iodine is water soluble and organic solvents.

Iodine is used to make dyes, develop images on photographic film, scientist use iodine to test the presence of starch on plant, chemist use iodine as an indicator in chemical reactions, physicians develop iodine laser as weapon. Iodine is represented as I in chemical symbol. Iodine's atomic number is 53 with 53 protons and 53 electrons. Iodine has an atomic mass of 127 with 74 neutrons in the nucleus of every iodine atom. Other synonyms of iodine includes: actomar, diodine, oranol, iodine-127 and molecular iodine

Iodine Absorption

Iodine is an essential micronutrient required in our body. Molecular iodine and inorganic iodine compounds are readily to be absorbed either through inhalation or orally or through dermal absorption. The best form of iodine absorption is in the water-soluble salts form whereby it will results in 100% absorption from our gastrointestinal tract. Meanwhile ingested inorganic iodine and iodate are reduced to iodide in the gut and can easily be absorbed by small intestine. Iodine is excreted through sweat, breast milk, urine and faces.

WHO recommended intake of iodine:
Category Intake amount
Adults and teens above age 13 years old 150 μg/day
Pregnant lady and lactation 2000 μg/day
Children age between 6 - 12 years old 120 μg/day
Children age 0 to 59 months old 90 μg/day

Lifetime exposure of 50 mg of potassium iodide per kg body weight per day can increase salivary gland tumors in rats.

Iodine allergy is a type IV reaction in classic allergic contact dermatitis, where iodine is bound within the benzoic acid ring structure.


Iodine Function?

There is about 3/5 of iodine is concentrated in human thyroid gland, some are present in blood circulation to boost up immune system and excessive will be filtered by kidney into urine. Iodine is needed in forming thyroid hormone called thyroxine especially T3 and T4. Thyroxine regulates and controlling our basal metabolic rate (BMR), influences our metal and physical growth, regulates our nervous function and muscle tissues. It is also crucial to act as an antiseptic and for treatment and diagnosis of various cancers.

Iodine Source

Ocean is a natural iodine source. Iodides in the sea accumulate in seaweed, salt water fish, sea salt, kelp, iodized salts and shellfish. Iodine appears as sea spray or gases. Vegetables grown on iodine soils near to sea-shore are also rich in iodine. Iodine also can be obtained from animal抯 diet.

Iodine Deficiency

  • Fatigue
  • Sluggishness
  • Weight gain
  • Coldness of the body
  • Endemic Goiter - lack of thyroxin level leads to enlargement of epithelial cells in the thyroid, creating a swelling in the neck trying to trap more iodine
  • Cretinism - occurs in infants called cretins when pregnant lady cannot provide sufficient iodine supply to fetus development. Cretins usually have thicker lips and enlarged tongue, low basal metabolism, metal and physical retardation.
  • Myxodema - the person's face becomes thick, puffy and physically inactive and normally occurs in adults
  • Sterility
  • Stillbirths
  • Increased susceptibility of thyroid gland to nuclear radiation in adults and children
  • Miscarriages
  • Congenital abnormalities
  • Cognitive function impairment
  • Hyperthyroidism
  • Thyroid cancer
  • Papillary cancer
In livestock, iodine deficiency can cause reduction of milk and meat yield, as well as lower wool production from sheep.

Iodine Side Effects

  • Fever
  • Hypothyroidism - Thyroid disorder due to excessive iodine that decreases T4 and T3 levels of circulation and induce hypothyroid
  • Goiter
  • Induced Febrile reactions
  • Iododerma - dermal sensitivity reaction due to excessive intake of organic iodine compound


  • Iodine By Leon Gray
  • Iodine and inorganic iodides: human health aspects by John F. Risher. L Samuel Keith, World Health Organization
  • Food & Nutrition Education By Punam Chopra
  • Elimination of Iodine Deficiency Disorders: A manual for health workers by Who Regional Office for Eastern Medi

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