Estimating the iodine supplementation level to recommend for pregnant and breastfeeding women in Australia.

OBJECTIVE To identify a level of iodine supplementation to recommend for pregnant and breastfeeding women in Australia. DESIGN, SETTING AND PARTICIPANTS Dietary modelling indicated that mandatory fortification of bread with iodine by replacing salt with iodised salt would still leave a gap in iodine intakes in pregnant and breastfeeding women in Australia. Iodine shortfall was estimated by two separate methods: (i) analysis of data from published studies reporting mean urinary iodine concentrations in populations of Australian women who were pregnant or had given birth in the past 6 months; and (ii) modelling based on the postmandatory fortification iodine intake estimates calculated by Food Standards Australia New Zealand using food consumption reported by women aged 19-44 years who participated in the 1995 National Nutrition Survey. MAIN OUTCOME MEASURE Estimated level of daily supplementation required to provide sufficient iodine to result in a low proportion of pregnant and breastfeeding women having inadequate iodine intakes. RESULTS Estimations from both data sources indicate that a supplement of 100-150 μg/day would increase iodine intakes to a suitable extent in pregnant and breastfeeding women in Australia. CONCLUSIONS The final level of supplementation we recommend should be based on these calculations and other factors. There will be population subgroups for whom our general recommendation is not appropriate.