Iodine intake of two-year-olds and adults in Iceland and estimation of the effect of using iodized salt in breads

Abstract

INTRODUCTION: Insufficient iodine status was recently identified in pregnant women in Iceland. Iodine fortification of salt is widely used to decrease the risk of iodine deficiency disorders, but the use of iodized salt has not been recommended in Iceland. The aim was to describe iodine intake among Icelandic adults and two-year-olds and estimate the effect of using iodized salt in bread. MATERIAL AND METHODS: Iodine intake was assessed using data from the Icelandic National Dietary Survey 2019-2021 (18-80 years, n=822) and a study of two-year-old children (n=124). Data on bread intake was used to estimate expected iodine intake if iodized salt was used in bread. The results are compared with recommended iodine intake (90 ug/day for two-year-olds and 150 ug/ day for adults) and upper intake level (200 ug/day and 600 ug/day, respectively). RESULTS: Average iodine intake was 88 ug/day for children and 134 ug/day for adults. If all types of bread consumed would contain 20 ug of iodine in 100 grams, the average iodine intake would increase to 99 and 153 ug/day, respectively. With higher bread iodine content, >5% of two-year-olds would exceed the upper intake level, while concentration up to 70 ug/100 grams of bread would result in iodine intake below the upper intake level for adults. CONCLUSION: Use of iodized salt in bread corresponding to 20ug of iodine in 100 grams of bread seems safe for young children in Iceland. However, based on the current dietary habits, adding this amount of iodine to bread would not be sufficient to secure optimal intake of iodine in all adults.