Last reviewed 06/2021

Iodine is the chemical element at number 53 in the periodic table, symbol I. It is an essential mineral that circulates within the body as the iodide ion.

It is an essential component of thyroid hormones. Excess iodide is excreted by the kidney. Hence, iodine status can be measured by either:

  • thyroid hormone assay
  • urinary iodine excretion

Sources include seafood, cod-liver oil, vegetables grown in iodine-rich soil, and iodised salt.

Iodine deficiency can cause goitre and cretinism.

Agents containing iodine have the prefix iodo-.