Iodine is an essential nutrient required for the production of thyroid hormones. These hormones are important for normal growth and development, particularly of the brain. The major dietary sources of iodine include seafood, especially seaweed, baked bread and dairy milk. Inadequate amounts of iodine may lead to a range of conditions, including goiter, hypothyroidism, and in severe cases, intellectual disability.¹
In October 2009, the mandatory fortification of baked bread with iodised salt was introduced in Australia in response to the re-emergence of mild levels of iodine deficiency in the population², particularly in Tasmania. The 2011–12 National Health Measures Survey (NHMS), which began 18 months after mandatory fortification was introduced, included a measure of urinary iodine excretion and is a key data source for measuring how effective mandatory fortification has been in increasing population iodine levels.
This article looks more closely at how iodine levels vary across the Australian population and how they may have changed in response to mandatory fortification.