Iodine is a naturally occurring mineral and an essential nutrient for life. It is found in the food we eat and the water we drink. Adequate intakes of dietary iodine by Australians, particularly females of child-bearing age and breast-feeding mothers is important for health and to reduce possible iodine-deficiency health problems such as impaired neurological function in babies and young children.
Mandatory iodine fortification was implemented in Australia in 2009 through Standard 2.1.1 of the Australia New Zealand Food Standards Code which required the replacement of non-iodised salt with iodised salt for making all breads except organic bread and bread mixes for making bread at home. Mandatory iodine fortification of bread was intended to address the re-emergence of iodine-deficiency in some areas of Australia and New Zealand.
To create alternative dietary iodine sources for people who don't eat bread, manufacturers have the opportunity to use iodised salt in other foods. The voluntary fortification permissions in the Code allow manufacturers to add iodised salt to bread mixes and other foods if they wished, but labelling requirements must be adhered to in that regard.
Iodised salt must be listed in the ingredient list of food labels where it has been used. Unpackaged bread and bread that is made and/or packaged at the point of sale is not required to be labelled. However, this information may be available on request.
Based on all available scientific evidence, adding iodised salt to bread is safe for the whole population.
The increased dietary iodine in bread is unlikely to cause harm to iodine sensitive individuals.
FSANZ consulted with an expert advisory group throughout development of the regulation, and concluded that the risk of any adverse health effects from mandatory iodine fortification of bread at the levels prescribed is very small across all population groups.
With the introduction of mandatory iodine fortification of bread through the use of iodised salt, the Australia and New Zealand Food Regulation Ministerial Council (now the Legislative and Governance Forum on Food Regulation) committed to a comprehensive and independent review of the program to begin two years after implementation.
Australian and New Zealand health authorities are monitoring the effectiveness of the increased amount of dietary iodine in the food supply. In Australia, Commonwealth and state/territory food regulatory authorities have undertaken a number of projects to monitor mandatory iodine fortification.
The findings of these projects have contributed to the planned review, the most recent report being from the Australian Institute of Health and Welfare (AIHW) on monitoring the health impact of mandatory folic acid and iodine fortification. The review report includes information on the nutrient content of bread, nutrient intakes, nutritional status, health benefits and possible adverse effects.
As part of its role in monitoring the Australian food supply, FSANZ conducted surveys of post mandatory fortification levels of iodine in commonly eaten breads on the Australian market. It also estimated the mean daily intake of dietary iodine by Australians of all age groups, particularly the target groups for iodine fortification (females of child-bearing age, breast-feeding mothers and children). The report on iodine fortification in Australia provides information on iodine levels in breads on the market through the national bread surveys, and the estimated intake of dietary iodine by the population (including target groups) before and after mandatory iodine fortification.
Estimates of iodine intake
The estimates of mean daily intake of dietary iodine indicate that there has been an increase in the intakes of all Australians including the target groups (29% increase in children aged 2-3 years; 52% increase in females of child-bearing age) and bread is the major food contributor to the increased intake. The increase was observed in the target population (females of child-bearing age) and the general adult population, resulting in an increase in the proportion of the population that met intake requirements for the nutrient.
The proportion of children (2-3 years) with inadequate intakes decreased from 9% to 1% after mandatory iodine fortification of bread. The proportion of females of children-bearing age (non-pregnant) estimated to have inadequate iodine intakes decreased from 60% to 9% following mandatory iodine fortification.
The expected positive health outcome from the estimated increase in dietary iodine intake is a reduction in the incidence of iodine-deficiency health problems, including impaired neurological function in children.
A New Zealand Ministry for Primary Industries report published in July 2014also found that the proportion of all children estimated to have inadequate iodine intakes in New Zealand had reduced from 95% to 21% post iodine fortification.