The first study to examine iodine status and iodine intake in children < 2 y of age in Innlandet County (Norway) and associations with maternal iodine nutrition is published in The Journal of Nutrition.
From the fetal stage into early childhood, thyroid hormones are crucial for neural and cognitive development. Iodine intake of exclusively breastfed infants relies entirely on maternal iodine status and intake. With the introduction of complementary foods, iodine can be obtained from iodine-rich food sources such as enriched infant cereals, fish, eggs, and cow’s milk. Although salt iodization programs have markedly improved iodine intake over the past decades, iodine deficiency is still of concern in countries where salt iodization programs are not established, such as Norway. Because studies reporting on iodine nutrition in early childhood are scarce, Tonje E. Aarsland (University of Bergen) and colleagues examined iodine status and intake in a representative sample of children 2 years of age and younger.
In this cross-sectional study, mother-child pairs from public health care centers were recruited from 30 randomly selected municipalities in Innlandet County in Norway from November 2020 until October 2021. Urinary iodine concentration was measured in urine samples of children and their mothers. A total of 326 urine samples from children were analyzed. Iodine was also measured in breastmilk to estimate iodine intake in breastfed children. Children’s usual iodine intake was estimated using two 24-hour dietary recalls and a food frequency questionnaire.
Based on the dietary data, 35 % of the children had suboptimal iodine intakes (below the Estimated average requirement of 72 g/day), whereas less than 1% had excessive intakes (above the Upper intake level of 200 g/day). Children’s iodine intake and urinary iodine concentration were positively associated with maternal iodine intake, breast milk iodine concentration, and maternal urinary iodine concentration.
This study is the first of its kind to present data on iodine status and intake in young children in Norway including both urinary iodine concentrations, estimated iodine intake, and associations with maternal iodine nutrition. The finding that 35% of the children had suboptimal iodine intakes is highly concerning and suggests that young children in Norway are at risk of iodine deficiency. The lack of a national salt iodization strategy in Norway has been largely attributed to concerns over the potential risk of excessive iodine intakes in young children. However, the results of this study indicate that the risk of iodine excess in this age group is low.
Aarsland TE, Solvik BS, Bakken KS, Naess Sleire S, Kaldenbach S, Holten-Andersen MN, Nermo KR, Fauskerud IT, Østvedt TH, Lohne S, Gjengedal ELF, Strand TA. Iodine Nutrition in Children < 2 years of Age in Norway. The Journal of Nutrition, Volume 153, Issue 11, November 2023, Pages 3237-3246, doi.org/10.1016/j.tjnut.2023.09.013.
Images via canva.com.