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Objective: Iodine is essential for thyroid hormone production. The recommended dietary allowance for iodine in nonpregnant adults is 150 μg/d. However, most product labels do not list the iodine content. Meal replacements are not required to contain specific vitamins and minerals. Nevertheless, they are often marketed as good and convenient sources of a balanced nutrition. In this study, we aimed to assess the iodine content in meal replacements to determine how they may contribute to iodine deficiency or excess., Methods: Twenty seven meal replacements from supermarkets in the Boston area were collected. The iodine concentration of each meal replacement was measured spectrophotometrically. Iodine content in meal replacements were compared according to form (liquid, bar, and powder) and type (vegan and nonvegan)., Results: The overall mean ± SD iodine content was 49.7 ± 125.4 μg/serving. However, 1 meal replacement was an outlier and had 671.9 μg iodine per serving. Mean iodine content differed between forms and was highest for liquids (mean ± SD: 37.4 ± 6.5 μg/serving). Nonvegan meal replacements had a higher mean iodine content than vegan meal replacements (mean ± SD: 31.6 ± 15.78 μg/serving)., Conclusion: All of the meal replacements contained detectible amounts of iodine regardless of whether it was listed on their labels (41% did not list iodine). Overall, the meal replacements in this study were found to be good sources of iodine. However, consumers should be aware that packaging labels may not accurately reflect the amount of iodine present., (Copyright © 2021 AACE. Published by Elsevier Inc. All rights reserved.)

Background: As iodine is a requisite micronutrient for infant brain development, infants are at risk for iodine deficiency during the weaning period when their diet transitions from milk (breast-milk, infant formula, or follow-on formula) to solid food. Dietary iodine intake during this weaning period is likely minimal, as the iodine content of commercial baby food is not regulated, and the addition of salt to baby food is not recommended. This study reports the current status of iodine nutrition among weaning infants in the United States., Methods: Subjects (n = 60; 50% Caucasian, 30% black) were infants <12 months of age who were fed any combination of formula and/or baby food. Samples of all formula and food consumed in the previous 24 hours and a spot urine sample from each infant were obtained for the measurement of iodine. The estimated quantities of ingested formula and baby food were summed from a food diary recorded by the infants' parents., Results: The mean age of the infants was 6.3 ± 3.5 months. The median urinary iodine concentration (UIC) was 117 μg/L (range 26.9-1302.8 μg/L). Estimated daily iodine intake obtained from the measured iodine content in infant formula/foods was 89 μg (range 0-288 μg). There was a positive correlation between the infants' UIC and the iodine content in the consumed foods (r = 0.4, p < 0.001)., Conclusions: Although the median UIC of infants fed a combination of infant formula and baby food would meet the criteria for iodine sufficiency in a larger sample, those consuming the lowest quartile of iodine-containing nutritional sources had a median UIC <100 μg/L.

Background: Thyroid hormone is essential for normal mental and physical development in infancy and childhood and is dependent on adequate iodine intake. During the first few months of life, infants are reliant on breastmilk and/or infant formula as their sole sources of dietary iodine. The iodine status of U.S. infants has not been well studied., Methods: This was a cross-sectional study of 95 breastfed and/or formula-fed infants less than 3 months of age in the Boston area. We measured iodine content from infants' single spot urine samples and assessed associations with infant feeding type as well as maternal demographic data, salt and multivitamin use, smoking status, and diet., Results: The median infant urine iodine concentration was 197.5 μg/L (range 40-897.5 μg/L). Median infant urine iodine concentrations were similar between infants who were exclusively breastfed (n=39, 203.5 μg/L; range 61.5-395.5 μg/L), formula-fed (n=44, 182.5 μg/L; range 40-897.5 μg/L), and mixed (n=10, 197.8 μg/L; range 123-592.5) (p=0.88). There were no significant correlations of infant urinary iodine with maternal salt or multivitamin use (regularly or in the past 24 hours), active or secondhand cigarette smoke exposures, infant weight, infant length, or recent maternal ingestion of common iodine-containing foods, although the correlations with iodine-containing foods are difficult to accurately determine due to the small sample sizes of these variables., Conclusions: Both breastfed and formula-fed infants less than 3 months of age in the Boston area were generally iodine sufficient. Larger studies are needed to confirm these observations among infants nationwide and elucidate other factors that may contribute to infant iodine nutrition.

Objective: To measure levels of colostrum iodine, which has not been previously measured, and perchlorate and cotinine (a surrogate for thiocyanate derived from cigarette smoke) in women up to 60 h postpartum. Perchlorate and thiocyanate are environmental inhibitors of iodide transport into the thyroid and lactating breast., Design: Cross-sectional., Patients: Ninety seven postpartum women in Boston, Massachusetts, USA., Measurements: Colostrum iodine and perchlorate, and spot urine iodine, perchlorate, cotinine and creatinine concentrations were measured., Results: Sufficient colostrum was obtained to measure iodine in 61 samples and perchlorate in 46 samples. Median colostrum iodine content was 51.4 micromol/l (range 21.3-304.2 microg/l). Perchlorate was detectable in 43 of 46 colostrum samples (median 2.5 micromol/l; range, < 0.05-188.9 micromol/l). Median urine iodine in 97 samples was 82.2 micromol/l (range, 10.3-417.1 micromol/l). Perchlorate was detectable in all 97 urine samples (median 2.6 micromol/l; range, 0.2-160.6 micromol/l). Colostrum iodine content was not significantly correlated with levels of colostrum perchlorate or concentrations per litre of urinary iodine, perchlorate, or cotinine. Colostrum perchlorate concentrations were not significantly associated with urinary iodine, perchlorate, or cotinine levels. Urinary cotinine levels were not significantly associated with urinary iodine or perchlorate levels. There was no association between maternal urinary iodine and urinary perchlorate levels., Conclusions: Iodine is present in human colostrum and thus available for breastfeeding infants immediately after birth. Perchlorate was also present in 93% of samples measured, but the concentrations did not correlate with colostrum iodine concentrations.

Context: Breastfed infants rely on adequate maternal dietary iodine intake., Objective: Our objective was to measure breast milk iodine and perchlorate, an inhibitor of iodide transport into the thyroid and potentially into breast milk, in Boston-area women., Participants: The study included 57 lactating healthy volunteers in the Boston area., Measurements: Breast milk iodine and perchlorate concentrations and urine iodine, perchlorate, and cotinine concentrations were measured. For comparison, iodine and perchlorate levels in infant formulae were also measured., Results: Median breast milk iodine content in 57 samples was 155 microg/liter (range, 2.7-1968 microg/liter). Median urine iodine was 114 microg/liter (range, 25-920 microg/liter). Perchlorate was detectable in all 49 breast milk samples (range, 1.3-411 microg/liter), all 56 urine samples (range, 0.37-127 microg/liter), and all 17 infant formula samples (range, 0.22-4.1 microg/liter) measured. Breast milk iodine content was significantly correlated with urinary iodine per gram creatinine and urinary cotinine but was not significantly correlated with breast milk or urinary perchlorate., Conclusions: Perchlorate exposure was not significantly correlated with breast milk iodine concentrations. Perchlorate was detectable in infant formula but at lower levels than in breast milk. Forty-seven percent of women sampled may have been providing breast milk with insufficient iodine to meet infants' requirements.

Dietary iodine is essential for thyroid hormone production. Although U.S. dietary iodine is generally adequate, some groups, especially women of childbearing age, are at risk for mild iodine deficiency. Children's average urinary iodine is higher than that of adults. U.S. dietary iodine sources have not been assessed recently. A survey of iodine content in 20 brands of bread, 18 brands of cows' milk, and eight infant formulae was performed between 2001 and 2002. Three bread varieties contained more than 300 microg iodine per slice. Iodine content in other brands was far lower (mean +/- sd, 10.1 +/- 13.2 microg iodine/slice). All cows' milk samples had at least 88 microg iodine/250 ml, ranging from 88-168 microg (116.0 +/- 22.1 microg/250 ml). Infant formulae values ranged from 16.2 to 56.8 microg iodine/5 oz (23.5 +/- 13.78 microg/5 oz). The public should be aware of the need for adequate dietary iodine intake and should be aware that ingredient lists do not reflect the iodine content of foods.