Outcomes of iodine fortification in Australia

In Australia, mandatory iodine fortification has increased the level of iodine in the food supply, and thereby increased iodine intakes and status among women of child-bearing age and young children (the key target populations) (Table 2). The population is consuming sufficient iodine to address the recent re-emergence of mild iodine deficiency.

Table 2: Key mandatory iodine fortification outcomes in Australia
Key monitoring question and measurement Pre-mandatory fortification Post-mandatory fortification Further details Outcome

Has the level of iodine in our food supply increased?
Mean iodine level of bread

<2 µg/100 g

53–70 µg/100 g

The predicted mandatory fortification level was 46 µg/100 g.

Desired outcome achieved

Are the food industries adequately complying with the mandatory fortification standards?

 Not applicable

Salt manufacturers and bakers have systems in place to ensure compliance.

 

Desired outcome achieved

Have iodine intakes in the population increased, particularly in women of child ‑bearing age and young children?
Mean iodine intakes

Women aged 16–44: 98 µg/day
Children aged 2–3: 127 µg/day

Women aged 16–44: 149 µg/day (51 µg/day increase; 52%)
Children aged 2–3: 164 µg/day (37 µg/day increase; 29%)

The predicted post‑fortification predicted increase was 46 µg/day among women aged 16–44 and 38 µg/day among children aged 2–3.
Iodine intakes sufficient for the general population.
Iodine supplementation for pregnant and breastfeeding women continues to be necessary (as expected when developing the mandatory fortification requirement).  

Desired outcome achieved

Proportion of the population with iodine intakes below the estimated average requirement (EAR)

Women aged 16–44 (non-pregnant EAR): 60%
Women aged 16–44 (pregnancy EAR): 95%
Women aged 16–44 (lactating EAR): 100%
Children aged 2–3: 9%

Women aged 16–44 (non-pregnant EAR): 9%
Women aged 16–44 (pregnancy EAR): 65%
Women aged 16–44 (lactating EAR): 85%
Children aged 2–3: <1%

Has the iodine status of the population improved, particularly in women of child‑bearing age and young children?
Median urinary iodine concentration (MUIC)

Children aged 8–10:
96 µg/L

Children aged 5–8: 175 µg/L
All women aged 16–44: 121 µg/L
Pregnant women aged 16–44: 116 µg/L
Breastfeeding women aged 16–44: 103 µg/L

Pre- and post-mandatory fortification data for children suggest an increase in MUIC.
MUIC for all women aged 16–44 and children aged 5–8 indicative of iodine adequacy.
Note, the MUIC for pregnant and breastfeeding women aged 16–44 is indicative of insufficient iodine intake post-fortification.  

Desired outcome achieved

Has the iodine status of the population improved?
Iodine status

Refer to information on nutrient status.

Does mandatory iodine fortification result in adverse health effects for the population?
Proportion of the population with iodine intakes above the upper level of intake (UL)

Women aged 16–44: 0%
Persons aged 17 and over: 0%
Children aged 4–8: 0%
Children aged 2–3: 7%

Women aged 16–44: 0%
Persons aged 17 and over: 0%
Children aged 4–8: <1%
Children aged 2–3: 20%

Minimal change in adults exceeding the UL. A higher proportion of children aged 2–3 exceeded the UL but is not considered a health risk. The UL for children is based on an end point for high intakes in adults. The proportion of young children exceeding the UL also decreases with age with <1% exceeding the UL after age 4.

Not applicable

Desired outcome achieved
Partial achievementPartial achievement
Not applicable: data did not support an overall assessment or a rating was not appropriate.

µg microgram
EAR estimated average requirement (for more information, see the Nutrient Reference Values for Australia and New Zealand website)
MUIC median urinary iodine concentration
UL upper level of intake (for more information, see the Nutrient Reference Values for Australia and New Zealand   website)

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