A lack of iodine causes goitre, and seafood and iodised salt are good sources of this important trace element, says Prof Allan Blackman from AUT, in ep 39 of Elemental.

The element iodine is often found in bathroom medicine cabinets, where it is used as an antiseptic for cuts and grazes.

It gets its name from the Greek work iodes, meaning violet.

Iodine (chemical symbol I, atomic number 53) is a non-metal, and shares a group with astatine, bromine, chlorine and fluorine.

Seaweeds have the ability to concentrate iodine from seawater which is why seaweeds, fish and shellfish are a good dietary source of this vital trace element.

The human thyroid gland concentrates iodine in the human body where it is used in two important hormones. A lack of iodine leads to goitre, and to prevent this it is added to table salt. In New Zealand, bakers must use iodised salt in bread, says Professor Allan Blackman from AUT.

Go to this episode on rnz.co.nz for more details