Abstract:Despite substantial progress in the global elimination of iodine deficiency, lactating mothers and their infants remain susceptible to insufficient iodine intake. This cross-sectional study was conducted to compare iodine statuses of breast-fed and formula-fed infants and their mothers at four randomly selected health care centres in Tehran. Healthy infants <3 months old and their mothers were randomly selected for inclusion in this study. Iodine was measured in urine and breast milk samples from each infant a… Show more
“…However, a higher mean age, lower breast-feeding rates and higher iodine intake from complementary foods in the two studies may explain the differences compared with our results. Unlike our results, several studies have not found an association between infant UIC and breast-feeding status (41)(42)(43)(44) . However, compared with our study, these studies reported adequate infant UIC and higher BMIC.…”
Adequate iodine nutrition during infancy is required for normal thyroid function and, subsequently, brain development. However, data on infant iodine status in the first year of life are scarce. This study aimed to describe infant iodine status and further explore its associations with maternal iodine nutrition, breastfeeding status and thyroid function. In this Norwegian cohort study, 113 infants were followed up at ages 3, 6, and 11 months. Infant and maternal urinary iodine concentration (UIC), maternal iodine intake, breast milk iodine concentration (BMIC), breastfeeding status and infant thyroid function tests were measured. The median infant UIC was 82 µg/L at age 3 months and below the WHO cut-off of 100 µg/L. Infant UIC was adequate later in infancy (median 110 µg/L at ages 6 and 11 months). Infant UIC was associated positively with maternal UIC (β= 0.33, 95% CI [0.12–0.54]), maternal iodine intake (β= 0.30, 95% CI [0.18–0.42]) and BMIC (β= 0.46, 95% CI [0.13–0.79]). Breastfed infants had lower median UIC compared with formula-fed infants at ages 3 months (76 vs. 190 µg/L) and 6 months (105 vs. 315 µg/L). Neither infant UIC nor BMIC were associated with thyroid function. In conclusion, breastfed infants in Norway are at risk of insufficient iodine intake during the first months of life. Maternal iodine nutrition is important for providing sufficient iodine intake in infants and awareness of promoting adequate iodine nutrition for lactating women should be prioritised.
“…However, a higher mean age, lower breast-feeding rates and higher iodine intake from complementary foods in the two studies may explain the differences compared with our results. Unlike our results, several studies have not found an association between infant UIC and breast-feeding status (41)(42)(43)(44) . However, compared with our study, these studies reported adequate infant UIC and higher BMIC.…”
Adequate iodine nutrition during infancy is required for normal thyroid function and, subsequently, brain development. However, data on infant iodine status in the first year of life are scarce. This study aimed to describe infant iodine status and further explore its associations with maternal iodine nutrition, breastfeeding status and thyroid function. In this Norwegian cohort study, 113 infants were followed up at ages 3, 6, and 11 months. Infant and maternal urinary iodine concentration (UIC), maternal iodine intake, breast milk iodine concentration (BMIC), breastfeeding status and infant thyroid function tests were measured. The median infant UIC was 82 µg/L at age 3 months and below the WHO cut-off of 100 µg/L. Infant UIC was adequate later in infancy (median 110 µg/L at ages 6 and 11 months). Infant UIC was associated positively with maternal UIC (β= 0.33, 95% CI [0.12–0.54]), maternal iodine intake (β= 0.30, 95% CI [0.18–0.42]) and BMIC (β= 0.46, 95% CI [0.13–0.79]). Breastfed infants had lower median UIC compared with formula-fed infants at ages 3 months (76 vs. 190 µg/L) and 6 months (105 vs. 315 µg/L). Neither infant UIC nor BMIC were associated with thyroid function. In conclusion, breastfed infants in Norway are at risk of insufficient iodine intake during the first months of life. Maternal iodine nutrition is important for providing sufficient iodine intake in infants and awareness of promoting adequate iodine nutrition for lactating women should be prioritised.
“…In our study, both children’s UIC and iodine intake were positively associated with all markers of maternal iodine nutrition (BMIC, UIC, and estimated iodine intake). This supports the importance of maternal iodine nutrition in providing sufficient iodine intake in young children and is also consistent with the findings of other studies [ 6 , [39] , [40] , [41] ]. FIGURE 3 Box plot of children’s dietary iodine intake by 24-HRs, stratified by the 3 age groups.…”
“… Association between BMIC (blue) and maternal UIC (orange) and/or infant UIC (yellow) from cross-sectional studies conducted in lactating mothers and their breastfed infants. Data points show median BMIC, median maternal UIC, and median infant UIC obtained in mother-infant pairs (sample size, n = 52-739) ( 112 , 145 , 146 , 166 , 167 , 203 , 204 , 211 , 246-258 ). The dashed lines indicate current thresholds for the median BMIC and median UIC above which the iodine intake is considered adequate ( 21 ).…”
Section: Iodine In Human Milkmentioning
confidence: 99%
“…Studies conducted in formula-fed infants report adequate median UIC ( 204 , 210 , 352 , 353 ), but data are limited. Some studies report lower median UIC in formula-fed infants compared to breastfed infants ( 210 , 352 , 354 ), whereas other studies observe no difference ( 204 , 353 ). The iodine intake depends on the iodine content in formula milk and the BMIC.…”
Iodine is a micronutrient needed for the production of thyroid hormones, which regulate metabolism, growth, and development. Iodine deficiency or excess may alter the thyroid hormone synthesis. The potential effects on infant development depend on the degree, timing, and duration of exposure. The iodine requirement is particularly high during infancy because of elevated thyroid hormone turnover. Breastfed infants rely on iodine provided by human milk, but the iodine concentration in breast milk is determined by the maternal iodine intake. Diets in many countries cannot provide sufficient iodine, and deficiency is prevented by iodine fortification of salt. However, the coverage of iodized salt varies between countries. Epidemiological data suggest large differences in the iodine intake in lactating women, infants, and toddlers worldwide, ranging from deficient to excessive intake. In this review, we provide an overview of the current knowledge and recent advances in the understanding of iodine nutrition and its association with thyroid function in lactating women, infants, and toddlers. We discuss risk factors for iodine malnutrition and the impact of targeted intervention strategies on these vulnerable population groups. We highlight the importance of appropriate definitions of optimal iodine nutrition and the need for more data assessing the risk of mild iodine deficiency for thyroid disorders during the first 2 years in life.
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