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

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 µg/day for two-year-olds and 150 µg/day for adults) and upper intake level (200 µg/day and 600 µg/day, respectively). RESULTS: Average iodine intake was 88 µg/day for children and 134 µg/day for adults. If all types of bread consumed would contain 20 µg of iodine in 100 grams, the average iodine intake would increase to 99 and 153 µg/day, respectively. With higher bread iodine content, >5% of two-year-olds would exceed the upper intake level, while concentration up to 70 µg/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 20µg 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.

Iodine status of pregnant women in a population changing from high to lower fish and milk consumption.

OBJECTIVES: Pregnancy is one of the most critical periods for iodine deficiency. The aim of the present study was to assess the iodine status and dietary intake of pregnant women in a population changing from high to lower consumption of milk and fish. DESIGN: Cross-sectional observational study. Urine samples were collected for measuring urinary iodine concentration (UIC) and creatinine, and blood samples for measuring serum thyroid-stimulating hormone (TSH). Frequency of consumption of selected food and beverages was obtained through a semi-quantitative validated FFQ. The difference in the distribution of UIC, ratio of iodine to creatinine (I:Cr) and TSH between groups following recommendations on fish and dairy product intake or not (fish ≥2 times/week as a main meal, diary products ≥2 portions/d) was assessed. SETTING: Primary Health Care of the Capital Area, Reykjavik, Iceland. SUBJECTS: Randomly selected pregnant women (19-43 years old, n 162). RESULTS: The median UIC was 180 µg/l, I:Cr 173 µg/g and TSH 1·5 mmol/l. Women who did not consume fish ≥2 times/week and also did not consume dairy products in line with the recommended intake level of ≥2 portions/d had median UIC of 160 µg/l (I:Cr 149 µg/g) compared with 220 µg/l (I:Cr 190 µg/g) in the group following both the recommendations for fish and those for dairy products. Use of dietary supplements in the two groups was similar. CONCLUSIONS: Iodine status in the population studied was within the optimal range (150-249 µg/d) defined by the WHO.