title: Direct iodine supplementation of infants versus supplementation of their breastfeeding mothers: a double-blind, randomised, placebo-controlled trial. Iodine Concentration in Breastmilk and Urine among Lactating Women of Bhaktapur, Nepal Reference values for spot urinary iodine concentrations in iodine-sufficient newborns using a new pad collection method. Iodine status and thyroid function of pregnant, lactating women and infants (0-1 yr) residing in areas with an effective Universal Salt Iodization program. Development of thyroid gland volume during the first 3 months of life in breast-fed versus iodine-supplemented and iodine-free formula-fed infants The nutritional iodine supply of Belgian neonates is still insufficient Breast-milk iodine concentration declines over the first 6 mo postpartum in iodine-deficient women. Perchlorate and iodide in dairy and breast milk. Dietary supplements for the lactating mother: influence on the trace element content of milk Urinary iodine excretion as a predictor of the iodine content of breast milk. Amelioration of some pregnancy-associated variations in thyroid function by iodine supplementation. Can postpartum maternal urinary iodine be used to estimate iodine nutrition status of newborns?
abstract: BACKGROUND Iodine deficiency in infants can damage the developing brain and increase mortality . Present recommendations state that oral iodised oil should be given to breastfeeding mothers to correct iodine deficiency in infancy when iodised salt is not available , and that direct supplementation should be given to infants who are not being breastfed or receiving iodine-fortified complimentary foods . However , there is little evidence for these recommendations . We aim ed to assess the safety and efficacy of direct versus indirect supplementation of the infant . METHODS We did this double blind , r and omised , placebo-controlled trial in Morocco . Healthy breastfeeding mothers and their term newborn babies ( aged ≤8 weeks ) were block r and omised by clinic day to receive either : one dose of 400 mg iodine to the mother and placebo to the infant ( indirect infant supplementation ) , or one dose of about 100 mg iodine to the infant and placebo to the mother ( direct infant supplementation ) . R and omisation was masked to participants and investigators . Co primary outcomes were : maternal and infant urinary iodine concentrations , breastmilk iodine concentration , maternal and infant thyroid-stimulating hormone ( TSH ) concentrations , maternal and infant thyroxine ( T4 ) concentrations , and infant growth . These outcomes were measured at baseline , and when infants were aged about 3 months , 6 months , and 9 months , and the two groups were compared using mixed effects models . This study is registered with Clinical Trials.gov , number NCT01126125 . FINDINGS We recruited 241 mother-infant pairs between Feb 25 , and Aug 10 , 2010 , and completed data collection by Aug 6 , 2011 . At baseline , median urinary iodine concentration was 35 μg/L ( IQR 29 - 40 ) in mothers and 73 μg/L ( 29 - 237 ) in infants , suggesting iodine deficiency . During the study , maternal urinary iodine concentration ( p=0.011 ) , breastmilk iodine concentration ( p<0.0001 ) , and infant urinary iodine concentration ( p=0.042 ) were higher in the indirect infant supplementation group than in the direct supplementation group . Maternal TSH ( p=0.276 ) and T4 ( p=0.074 ) concentrations did not differ between the groups over the course of the study , nor did infant TSH ( p=0.597 ) and T4 ( p=0.184 ) concentrations , but the number of infants with thyroid hypofunction was lower ( p=0.023 ) in the indirect supplementation group than the direct supplementation group . The infant groups did not differ in anthropomorphic measures , except that length-for-age Z score was slightly greater in the direct infant supplementation group ( p=0.032 ) . At 3 months and 6 months of age , median infant urinary iodine concentration in the indirect infant supplementation group was sufficient ( > 100 μg/L ) , whereas infant urinary iodine concentration was sufficient only at 6 months in the direct supplementation group . There were no serious adverse events in either group . INTERPRETATION In regions of moderate-to-severe iodine deficiency without effective salt iodisation , lactating women who receive one dose of 400 mg iodine as oral iodised oil soon after delivery can provide adequate iodine to their infants through breastmilk for at least 6 months , enabling the infants to achieve euthyroidism . Direct supplementation is less effective in improving infant iodine status . FUNDING ETH Zurich , Switzerl and ; the Medicor Foundation , Vaduz , Lichtenstein Adequate iodine concentration in breastmilk ( BMI C ) is essential for optimal neonatal thyroid hormone synthesis and neurological development in breastfed infants . For many decades , iodine deficiency has been a public health problem in Nepal . However , recently , excessive iodine intakes among Nepali infants have been reported . This study aim ed to measure BMI C and urinary iodine concentration ( UIC ) among lactating women in a peri-urban area of Nepal .  Iodine concentration was measured in spot urine ( n = 485 ) and breastmilk sample s ( n = 291 ) of 500 r and omly selected lactating women . The median ( p25 , p75 ) BMI C and median UIC were 250 ( 130 , 370 ) µg/L and 230 ( 135–377 ) µg/L , respectively . Around 82 % had BMI C > 100 µg/L , 61 % had BMI C > 200 µg/L and 81 % had UIC > 100 µg/L , 37 % had > 300 µg/L and 20 % had > 500 µg/L. In multiple linear regression models , time since birth ( β 3.0 , 95 % CI ( 0.2 , 5.0 ) ) and UIC ( β 1.0 , 95 % CI ( 0.1 , 2.0 ) ) were associated with BMI C , explaining 26 % of the variance . A large proportion of the women had adequate BMI C and UIC ; however , a subset had high iodine concentrations . These findings emphasize the importance of carefully monitoring iodine intake to minimize the risk of iodine excess and subsequently preventing transient iodine-induced hypothyroidism in breastfed infants BACKGROUND Iodine deficiency in infancy can impair neurocognitive development , but there are few available indicators of iodine intake during this critical period . In many countries , access to newborns in maternity clinics in the first few days after birth is high . If spot urine sample s could be collected , reference data for urinary iodine concentration ( UIC ) would be useful to evaluate their iodine status . The study objectives were 1 ) to develop and vali date a simple pad system for collection of spot urine sample s for iodine ; 2 ) to establish a reference range for UIC in newborns in the first week after birth for use in monitoring iodine nutrition . METHODS A two-stage cluster sampling was used to obtain a representative national sample of healthy , term Swiss infants , 0 to 5 days old ( n = 634 ) .  Gestational information , whole blood for thyrotropin , and spot urine sample s on two consecutive days were collected . RESULTS The pad collection system was well-accepted and performed well during recovery and contamination testing . Median UIC in the total sample ( n = 1224 ) was 77 ( 95 % confidence interval ; 76 , 81 ) microg/L ; there was a gradual increase in median UIC within the range of 70 - 100 microg/L from days 1 through 4 . Because urinary creatinine concentrations were high and variable , the UI : creatinine ratio was not useful for st and ardization . CONCLUSIONS The current WHO median UIC cut-off ( > 100 microg/L ) for iodine sufficiency in infancy may be too high for the first week after birth . Reference data from iodine-sufficient newborns and a simple collection system may facilitate use of UIC as an indicator of iodine status in this age group OBJECTIVE To assess the iodine nutrition and thyroid function of pregnant women , lactating women and infants residing in areas where the Universal Salt Iodization program is in place . METHODS Pregnant women , lactating women and infants were selected r and omly in the regions where iodized salt coverage rate is more than 90 % since 2000 .  Urine iodine levels of pregnant woman , lactating woman and infants , milk iodine of lactating woman , thyroid-stimulating hormone ( TSH ) and free T4 of women were tested respectively . RESULTS Median Urinary Iodine ( MUI ) of infants , three groups of pregnant women ( first , second and third trimester ) and two groups lactating women ( breastfeeding less than or more than six months ) were 233 , 174 , 180 , 147 , 126 and 145 microg/L , respectively . Median milk iodine of lactating women was 163 microg/L. Percentage of milk iodine < 150 microg/L of early lactating women was 40 % less than that of late lactating women ( p < 0.01).There was a positive correlation between urine iodine of infants and milk iodine of lactating women ( r = 0.526 , p = 0.000 ) . T4 of two women were above or below the reference range . Total 15.4 % women 's TSH were abnormal . Most of these women 's urinary iodine were lower than 150 microg/L. CONCLUSION Iodine status of most of the target population for Universal Salt Iodization program is adequate , but iodine deficiency still existed in some . To assure every new life 's brain not be damaged by iodine deficiency , iodine status of targeted population s should be monitored and supplements provided according to the monitoring outcomes Summary The spontaneous development of thyroid gl and volume ( TGV ) during the first 3 months of life was studied in entirely breast-fed infants ( n = 21 ) and compared to those fed an iodine-supplemented formula ( n = 19 ) , an iodine-free formula ( n = 5 ) , or partially breast-fed in addition to an iodine-free ( n = 4 ) or an iodine-supplemented formula ( n = 16 ) . The TGV of the infants and their mothers was determined sonographically in addition to their urinary iodine concentrations 57 days postpartum and 3 months later . In ten additional lactating mothers the breast milk concentrations of thyroid hormones and iodine were determined . It was shown that at 3 months of age an infant consuming about 1000 ml breast milk per day receives about 2 μg thyroid hormones and 55 μg iodine per day . At the end of their first week of life the infants showed a TGV between 0.28 and 1.5 ml ( median 0.61 ml ) and a urinary iodine concentration between 0.03 and 16.3 μg/dl ( median 3.0 μg/dl ) . At 3 months of age the TGV of the breast-fed infants had decreased by a median of 0.24 ml (= −34 % ; median of percentage changes ) whereas those fed a formula without iodine had increased by a median of 0.26 ml (= + 50 % ; median of percentage changes ) . Those receiving an iodine-supplemented formula  showed a TGV reduction of 0.14 ml (= + 2 % ; median of percentage changes ) . The TGV development of the partially breast-fed infants lay between those being exclusively breast or formula fed . It is concluded that with respect to the development of TGV , breast milk is superior even to the feeding of an iodine-supplemented formula Abstract . Belgium used to be affected by mild iodine deficiency . Improvement in iodine nutrition has been recently documented in schoolchildren in Belgium in spite of the absence of any systematic programme of iodine supplementation . The question arises as to whether this ' silent iodine prophylaxis ' affected also the neonates . A total of 185 r and om urine sample s were collected from 90 full term and 65 preterm neonates in Brussels on day 5 and repeated on day 30 in 30 preterms who were bottle-fed with iodine-enriched formula-milk . The iodine content was also determined in 58 sample s of breast-milk on day 5 . The median urinary iodine on day 5 in full term neonates was 86 µg/l , which is markedly higher than the figure of 48 µg/L reported 15 years previously in neonates in the same area but still much lower than normal for this age group ( 150–200 µg/l ) . The mean iodine content of breast-milk was 78 µg/l , which is unchanged as compared to 15 years ago and is about 66 % of normal . Finally , the median urinary iodine increased from 60 µg/l on day 5 to 150 µg/l on day 30 in preterms bottle-fed with iodine-enriched formula-milk . Conclusion : the status of iodine nutrition has also improved spontaneously in Belgian neonates but has not yet normalised . Lactating and probably pregnant women remain clearly iodine deficient . The iodine-enriched formula-milk for preterms is efficient in correcting their iodine deficiency . National measures are urgently required for correction of iodine deficiency in Belgium BACKGROUND Little is known about the iodine status of lactating mothers and their infants during the first 6 mo postpartum or , if deficient , the amount of supplemental iodine required to improve status . OBJECTIVE The objective was to determine maternal and infant iodine status and the breast-milk iodine concentration ( BMI C ) over the first 6 mo of breastfeeding . DESIGN A r and omized , double-blind , placebo-controlled supplementation trial was conducted in lactating women who received placebo ( n = 56 ) , 75 μg I/d ( n = 27 ) , or 150 μg I/d ( n = 26 ) after their infants ' birth until 24 wk postpartum .  Maternal and infant urine sample s and breast-milk sample s were collected at 1 , 2 , 4 , 8 , 12 , 16 , 20 , and 24 wk . Maternal serum thyrotropin and free thyroxine concentrations were measured at 24 wk . RESULTS Over 24 wk , the median urinary iodine concentration ( UIC ) of unsupplemented women and their infants ranged from 20 to 41 μg/L and 34 to 49 μg/L , respectively , which indicated iodine deficiency ( ie , UIC < 100 μg/L ) . Mean maternal UIC was 2.1 - 2.4 times higher in supplemented than in unsupplemented women ( P < 0.001 ) but did not differ significantly between the 2 supplemented groups . BMI C in the placebo group decreased by 40 % over 24 wk ( P < 0.001 ) and was 1.3 times and 1.7 times higher in women supplemented with 75 μg I/d ( P = 0.030 ) and 150 μg I/d ( P < 0.001 ) , respectively , than in unsupplemented women . Thyrotropin and free thyroxine did not differ significantly between groups . CONCLUSION BMI C decreased in the first 6 mo in these iodine-deficient lactating women ; supplementation with 75 or 150 μg I/d increased the BMI C but was insufficient to ensure adequate iodine status in women or their infants . The study was registered with the Australian New Zeal and Clinical Trials Registry as ACTRN12605000345684 Perchlorate inhibits iodide uptake and may impair thyroid and neurodevelopment in infants . Recently , we unambiguously identified the presence of perchlorate in all seven br and s of dairy milk r and omly purchased from grocery stores in Lubbock , TX . How widespread is perchlorate in milk ?  Perchlorate  in 47 dairy milk sample s from 11 states and in 36 human milk sample s from 18 states were measured . Iodide was also measured in a number of the sample s.  Perchlorate  was detectable in 81 of 82 sample s. The dairy and breast milk means were , respectively , 2.0 and 10.5 microg/L with the corresponding maximum values of 11 and 92 microg/L.  Perchlorate  is present in virtually all milk sample s , the average concentration in breast milk is five times higher than in dairy milk . Although the number of available measurements are few at this point , for breast milk sample s with a perchlorate content greater than 10 microg/L , the iodide content is linearly correlated with the inverse of the perchlorate concentration with a r2 of > 0.9 ( n = 6 ) . The presence of perchlorate in the milk lowers the iodide content and may impair thyroid development in infants . On the basis of limited available data , iodide levels in breast milk may be significantly lower than it was two decades ago . Recommended iodine intake by pregnant and lactating women may need to be revised upward Milk production is a complex process where nutritional factors interact with structural hormonal and behavioural influences . In recent years important advances have been made in underst and ing the role of the nutritional status of lactating women on the outcome of breastfeeding . Many questions remain unanswered about the exact requirement of trace elements for lactating mothers . The effect of dietary zinc , copper and iodine supplements on the milk concentration of these micronutrients was studied . The supplementation trial employed a specific balanced nutritional supplement prepared for the nursing mothers . The study was carried out on women living in Ferrara and its surrounding area . The population under study was healthy Italian mothers , of good socioeconomic status , and their normal infants . In total , 32 women were enrolled in the study and 22 completed it . The infants ( 9F , 13 M ) were full‐term , healthy singletons and were put to breast within 12 h of birth . All women who finished the study completed a 3 d dietary record . Nutrient analysis revealed the following mean daily dietary trace element intake in the lactating mothers : zinc = 12 mg , copper = 1.4 mg and iodine = 145 μg . The zinc and copper dietary intake was in agreement with the daily intake proposed for nursing Italian mothers , while the daily intake of iodine was below the recommended intake of 200 μg . The breastfeeding mothers were placed in 2 groups , with 7 primiparas and 4 multiparas per group : lactating women eating a traditional Italian diet without vitamin and mineral supplements  , and lactating women enrolled in the nutrification programme  and given a nutritional supplement to their traditional diet . The supplement ( PerMamma Abbott ) provided 20 mg zinc sulfate , 2 mg copper sulfate and 116 μg potassium iodide . These quantities cover about 60‐90 % of the recommended intake for nursing Italian mothers . Sample s of 10 ml of milk were collected at 3 , 30 , 90 d postpartum . Zinc milk concentrations declined significantly over the study period for all lactating subjects , without differences in the rate of decline between the women who started supplementation during lactation and those who did not . Copper did not change during the first month of lactation , then declined at day 90 in supplemented and unsupplemented women , without significant differences between the two groups . An early sharp decline in milk iodine occurred in all lactating subjects , independently of iodine supplementation . After the first month of lactation breast milk iodide levels remained stable in all subjects under study . No significant differences between the two study groups were observed . The lack of correlation between the iodide level in breast milk and maternal dietary intake of iodine is not in agreement with previously published reports . The present results indicate that in healthy , well‐nourished lactating Italian women , whose diet is adequate , the levels of zinc , copper and iodine in milk are not influenced by short‐term supplementary intakes and that the milk levels of the trace elements studied are maintained over different levels of intake . Further research and examination by longitudinal studies are needed to establish the exact relationship between the amount of iodine furnished to the nursing mother and the iodine content of human milk . The role of compensatory homeostatic mechanisms which act during lactation needs further consideration and closer scrutiny Endemic goitre has re-emerged in Thail and . This is particularly dangerous for children since iodine deficiency disorders ( IDDs ) might negatively influence their intellectual and mental development . In order to assess the situation , the iodine content of breast milk was determined and a method is proposed on how to monitor IDDs in lactating mothers later on . Seventy-five lactating women aged from 15 to 45 years , from 12 villages of 3 districts , namely Chumpae . Srichompu and Pupaman within the mountainous areas of Khon Kaen province , Northeast of Thail and were investigated . The breast milk from 46.7 per cent of mothers was found to be below recommended st and ards . In addition , 52.0 per cent of the women investigated had low urinary iodine excretion . The risk of women with low iodine excretion was 15 fold higher in comparison to women with sufficient iodine excretion to provide breast milk for their babies with insufficient iodine content . It is concluded that urinary iodine excretion can be used to monitor the IDDs in lactating mothers Knowledge of the effect of differences in iodine intake levels on public health in areas with no endemic goiter is limited . Groups at risk when iodine intake is relatively low are pregnant and lactating women and their newborns . A prospect i ve r and omized study was performed to evaluate the effect of iodine supplementation in an area where the median daily iodine excretion in urine is around 50 micrograms . Fifty-four normal pregnant women were r and omized to be controls or to receive 200 micrograms iodine/day from weeks 17 - 18 of pregnancy until 12 months after delivery . In the control group , serum TSH , serum thyroglobulin ( Tg ) , and thyroid size showed significant increases during pregnancy . These variations were ameliorated by iodine supplementation . Iodine did not induce significant variations in serum T4 , T3 , or free T4 . Cord blood Tg was much lower when the mother had received iodine , whereas TSH , T4 , T3 , and free T4 levels were unaltered . The results suggest that a relatively low iodine intake during pregnancy leads to thyroidal stress , with increases in Tg release and thyroid size . However , the thyroid gl and is able to adapt and keep thyroid hormones in the mother and the child normal , at least under normal circumstances , as evaluated in the present study . It is not known whether this stress is sufficient to be of importance for late development of autonomous thyroid growth and function I deficiency can lead to detrimental effects , particularly in neonates and young infants . The aim of this study was to explore whether postpartum maternal urinary I can be used to estimate the I status of newborns . In this cross-sectional study conducted in Tehran , lactating mothers and newborns , within 3 - 5 d postpartum , were r and omly selected .  Urine sample s were collected from each mother and newborn , and a heel-prick blood sample was obtained from all newborns as part of the routine national newborn screening programme . According to the WHO criteria , median urinary I concentration ( UIC ) 5 mIU/l was considered as I insufficiency . A total of 147 postpartum women and neonates , aged 27·8 ( SD 5·3 ) years and 4·2 ( SD 0·6 ) d , respectively , completed this study  . The median UIC was 68·0 ( interquartile range ( IQR ) 39·4 - 133·5 ) and 212·5 ( IQR 92·3 - 307·3 ) µg/l in postpartum mothers and newborns , respectively . The median neonatal TSH was 1·00 ( IQR 0·50 - 1·70 ) mIU/l . There was no significant difference in the neonatal UIC and TSH of infants whose mothers had deficient and sufficient urinary I. In the multiple linear regression , neonatal UIC value was associated with maternal urinary I ( P=0·048 ) and parity ( P=0·039 ) ; a significant association was observed between neonatal TSH and infant sex ( P=0·038 ) and birth weight ( P=0·049 ) . The findings of our study demonstrate that , despite postpartum mothers being mildly I deficient , I status of their infants was adequate as assessed by UIC and TSH values . It seems factors other than maternal urinary I may influence the I status in newborns
target: The results are thus compatible with the international recommendation that lactating women and infants younger than two years of age who reside in iodine-sufficient countries do not require iodine supplementation
background: BACKGROUND Iodine , an essential micronutrient , plays a critical role in normal growth and development , especially during the first two years of life .
  This systematic review and meta- analysis is among the first to evaluate breast-milk iodine concentrations and infant iodine status in countries characterized by iodine sufficiency or deficiency .