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Wang Y, Tian X, Song Q, Wang W, Guo X, Cui T, Pan Z, Chen Y, Chen W, Tan L, Zhang W. Application and Comparison of Different Regression Models in Iodine Balance Experiment on Women of Childbearing Age and Pregnant Women. Biol Trace Elem Res 2024; 202:2474-2487. [PMID: 37807000 DOI: 10.1007/s12011-023-03867-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 09/12/2023] [Indexed: 10/10/2023]
Abstract
The iodine balance experiment is a traditional approach to evaluate the physiological requirement for iodine, while the simple linear regression model (SLM) and the mixed effects model (MEM) are two primary methods used to analyze iodine balance experiments. In the present study, we aimed to compare the effects of these two regression models on the evaluation of iodine balance experiments to investigate appropriate valuation methods. By constructing SLM and MEM, zero iodine balance values (IBV) were determined, and the evaluation effects were compared. No changes were made to the experimental data for women of childbearing age, and cutoff values of 600 µg/day and 1000 µg/day, respectively, were chosen for further processing of the experimental data for pregnant women. Equation combinations 1-3 (EC1-3) were obtained by fitting SLM, and zero IBV were calculated as 110.26 µg/day, 333.06 µg/day, and 434.84 µg/day, respectively. EC4-6 were obtained by fitting MEM, and zero IBV were calculated as 110.44 µg/day, 335.79 µg/day, and 418.06 µg/day, respectively. The inclusion of inter-measurement variation as a random factor in the MEM yielded EC7-8, which reduced the test power of the iodine balance experiment on women of childbearing age. Our study suggested that when experimental conditions were tightly controlled, with fewer uncertainties or significant influences, computationally straightforward and well-understood SLM was preferred. If some uncertain factors might cause large changes in the experimental results, it was advised to use a more "conservative" MEM to calculate the zero IBV. ClinicalTrials.gov Identifier: Registered at Clinicaltrials.gov, NCT03279315 (17th September 2017, retrospectively registered), NCT03710148 (18th October 2018, retrospectively registered).
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Affiliation(s)
- Yu Wang
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, China
| | - Xiaoxiao Tian
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, China
- Tianjin Third Central Hospital Nutrition Department, Tianjin, China
| | - Qiuyi Song
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, China
| | - Wenqiang Wang
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, China
| | - Xiaohui Guo
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, China
- Tianjin Nankai District Center for Disease Control and Prevention, Tianjin, China
| | - Tingkai Cui
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, China
| | - Ziyun Pan
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, China
| | - Yongjie Chen
- Department of Epidemiology and Health Statistics, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Wen Chen
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, China
| | - Long Tan
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, China.
| | - Wanqi Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin, China
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Liu S, Sharp A, Luo X, Lane S, Villanueva EV, Lu Z, Ma ZF. The use of breast milk iodine concentration in the first week of lactation as a biomarker of iodine status in breast-feeding women. Br J Nutr 2024; 131:286-295. [PMID: 37642155 DOI: 10.1017/s0007114523001897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Breast milk iodine concentration (BMIC) is a promising indicator of iodine status in lactating women. However, there are limited data on its usefulness to reflect maternal iodine deficiency. Therefore, the aim of our study was to assess iodine concentration in breast milk and urine samples in exclusively breast-feeding women. Eligible pregnant women undergoing routine antenatal care in a large hospital in Shaanxi Province, China, were followed up from the third trimester of pregnancy until the first week of lactation. Urine samples (20 ml) were collected during pregnancy and lactation. Iodine concentration in samples was measured based on Sandell-Kolthoff reaction. Breast milk samples (5 ml) were provided during lactation. A receiver operating curve (ROC) was constructed to determine the diagnostic performance of BMIC. An iodine-specific FFQ was completed twice during pregnancy and lactation. A total of 200 women completed the study. The overall median BMIC was 89 μg/l, indicating iodine sufficiency (i.e. BMIC reference range between 60 and 465 μg/l). Women reported similar median urinary iodine concentration (UIC) during pregnancy and lactation (112 and 113 μg/l, respectively), but their iodine status differed - mild-to-moderate iodine deficiency during pregnancy and iodine sufficiency during lactation. The ROC for BMIC using UIC as a reference standard was 0·755 (95 % CI: 0·644, 0·866). In conclusion, this study demonstrated that women were iodine sufficient in the first week of lactation as assessed by UIC, which was consistent with BMIC. These findings suggested that BMIC is a useful biomarker to assess iodine status in lactating women.
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Affiliation(s)
- Shuchang Liu
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou215123, People's Republic of China
- Harris-Wellbeing Research Centre, Faculty of Health & Life Sciences, University of Liverpool, LiverpoolL8 7SS, UK
| | - Andrew Sharp
- Harris-Wellbeing Research Centre, Faculty of Health & Life Sciences, University of Liverpool, LiverpoolL8 7SS, UK
| | - Xiaoqin Luo
- School of Public Health, Xi'an Jiaotong University, Xi'an710006, People's Republic of China
| | - Steven Lane
- Health Data Science, University of Liverpool, Liverpool, UK
| | - Elmer V Villanueva
- School of Science, Xi'an Jiaotong-Liverpool University, Suzhou215123, People's Republic of China
- Victoria University, Footscray Victoria Melbourne3011, Australia
| | - Zhiliang Lu
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou215123, People's Republic of China
| | - Zheng Feei Ma
- School of Science, Xi'an Jiaotong-Liverpool University, Suzhou215123, People's Republic of China
- Centre for Public Health and Wellbeing, School of Health and Social Wellbeing, College of Health, University of the West of England, BristolBS16 1QY, UK
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Gunnarsdóttir I, Brantsæter AL. Iodine: a scoping review for Nordic Nutrition Recommendations 2023. Food Nutr Res 2023; 67:10369. [PMID: 38187800 PMCID: PMC10770700 DOI: 10.29219/fnr.v67.10369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 04/27/2022] [Accepted: 11/10/2023] [Indexed: 01/09/2024] Open
Abstract
Iodine is essential for the synthesis of the thyroid hormones thyroxine (T4) and triiodothyronine (T3). As in many other parts of the world, insufficient iodine intake and consequently insufficient iodine status is a public health challenge in the Nordic and Baltic countries. The main dietary sources of iodine in the Nordic and Baltic countries include cow's milk, saltwater fish, eggs, products containing iodised salt, and iodised table salt. Only Denmark (DK), Finland (FI) and Sweden (SE) have implemented mandatory (DK) or voluntary (SE, FI) salt iodisation. New data, as well as recent studies from the Nordic and Baltic countries, strengthen the evidence that the main health challenges related to insufficient iodine intake remain thyroid function and thyroid disease, mental development, and cognitive function. Excessive intakes can also cause hyperthyroidism, autoimmune thyroid disease, and thyroid cancer.
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Affiliation(s)
- Ingibjörg Gunnarsdóttir
- Faculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland
- Unit for Nutrition Research, Landspitali National University Hospital, Reykjavik, Iceland
| | - Anne Lise Brantsæter
- Department of Food Safety, Division of Climate and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
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Aarsland TE, Solvik BS, Bakken KS, Sleire SN, 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. J Nutr 2023; 153:3237-3246. [PMID: 37742796 PMCID: PMC10687616 DOI: 10.1016/j.tjnut.2023.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 09/14/2023] [Accepted: 09/19/2023] [Indexed: 09/26/2023] Open
Abstract
BACKGROUND As a component of the thyroid hormones (THs), iodine is vital for normal neurodevelopment during early life. However, both deficient and excess iodine may affect TH production, and data on iodine status in young children are scarce. OBJECTIVES To describe iodine nutrition (iodine status and intake) in children ≤2 y of age in Innlandet County (Norway) and to describe the associations with maternal iodine nutrition. METHODS A cross-sectional study was performed in a representative sample of mother-child pairs selected from 30 municipalities from November 2020 until October 2021. Iodine status [child urinary iodine concentration (UIC), maternal UIC, and breast milk iodine concentration (BMIC)] was measured. Child's iodine intake was estimated using 2 24-h dietary recalls (24-HR) and a food frequency questionnaire. The Multiple Source Method was used to estimate the usual iodine intake distributions from the 24-HR assessments. RESULTS The median UIC in 333 children was 145 μg/L, indicating adequate iodine status according to the WHO cutoff (100 μg/L). The median usual iodine intake was 83 μg/d. Furthermore, 35% had suboptimal usual iodine intakes [below the proposed Estimated average requirement (72 μg/d)], whereas <1% had excessive usual iodine intakes [above the Upper intake level (200 μg/d)]. There was a positive correlation between children's iodine intake and BMIC (Spearman rank correlation coefficient r = 0.67, P < 0.001), and between children's UIC and BMIC (r = 0.43, P < 0.001), maternal UIC (r = 0.23, P = 0.001), and maternal iodine intake (r = 0.20, P = 0.004). CONCLUSION Despite a median UIC above the cutoff for iodine sufficiency, more than a third of the children had suboptimal usual iodine intakes. Our findings suggest that many children will benefit from iodine fortification and that risk of iodine excess in this age group is low.
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Affiliation(s)
- Tonje E Aarsland
- Center of International Health, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway; Women's Clinic at Lillehammer Hospital, Innlandet Hospital Trust, Lillehammer, Norway.
| | - Beate S Solvik
- Center of International Health, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway; Women's Clinic at Lillehammer Hospital, Innlandet Hospital Trust, Lillehammer, Norway
| | - Kjersti S Bakken
- Center of International Health, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway; Women's Clinic at Lillehammer Hospital, Innlandet Hospital Trust, Lillehammer, Norway
| | - Synnøve Næss Sleire
- Seafood, Nutrition and Environmental State, Institute of Marine Research, Bergen, Norway
| | - Siri Kaldenbach
- Department of Paediatric and Adolescent Medicine, Innlandet Hospital Trust, Lillehammer, Norway; Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Mads N Holten-Andersen
- Department of Paediatric and Adolescent Medicine, Innlandet Hospital Trust, Lillehammer, Norway; Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Kristina R Nermo
- Center of International Health, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway; Department of Microbiology, Innlandet Hospital Trust, Lillehammer, Norway
| | - Ingunn T Fauskerud
- Department of Microbiology, Innlandet Hospital Trust, Lillehammer, Norway
| | - Thobias H Østvedt
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway
| | - Solfrid Lohne
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway
| | - Elin L F Gjengedal
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway
| | - Tor A Strand
- Center of International Health, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway; Department of Research, Innlandet Hospital Trust, Lillehammer, Norway
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5
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Liu X, Wang J, Li Y, Tan H, Li X, Mao D, Liu Y, Li W, Yu W, Lu J, Yan J, Piao J, Yang L, Guo C, Liu X, Yang X. Re-exploration of dietary iodine intake in Chinese adult males using a modified iodine balance study. Br J Nutr 2023; 130:1308-1315. [PMID: 36876640 DOI: 10.1017/s0007114523000569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
There is still controversy about optimal dietary iodine intake as the Universal Salt Iodization policy enforcement in China. A modified iodine balance study was thus conducted to explore the suitable iodine intake in Chinese adult males using the iodine overflow hypothesis. In this study, thirty-eight apparently healthy males (19·1 (sd 0·6) years) were recruited and provided with designed diets. After the 14-d iodine depletion, daily iodine intake gradually increased in the 30-d iodine supplementation, consisting of six stages and each of 5 d. All foods and excreta (urine, faeces) were collected to examine daily iodine intake, iodine excretion and the changes of iodine increment in relation to those values at stage 1. The dose-response associations of iodine intake increment with excretion increment were fitted by the mixed effects models, as well as with retention increment. Daily iodine intake and excretion were 16·3 and 54·3 μg/d at stage 1, and iodine intake increment increased from 11·2 μg/d at stage 2 to 118·0 μg/d at stage 6, while excretion increment elevated from 21·5 to 95·0 μg/d. A zero iodine balance was dynamically achieved as 48·0 μg/d of iodine intake. The estimated average requirement and recommended nutrient intake were severally 48·0 and 67·2 μg/d, which could be corresponded to a daily iodine intake of 0·74 and 1·04 μg/kg per d. The results of our study indicate that roughly half of current iodine intakes recommendation could be enough in Chinese adult males, which would be beneficial for the revision of dietary reference intakes.
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Affiliation(s)
- Xiaobing Liu
- Chinese Center for Disease Control and Prevention, National Institute for Nutrition and Health, Beijing100050, People's Republic of China
- Shenzhen Center for Chronic Disease Control, Shenzhen, Guangdong518020, People's Republic of China
| | - Jun Wang
- Shenzhen Polytechnic, School of Food and Drug, Shenzhen, Guangdong518055, People's Republic of China
| | - Yajie Li
- Changzhi Medical College, Changzhi, Shanxi046000, People's Republic of China
| | - Hongxing Tan
- Shenzhen Center for Chronic Disease Control, Shenzhen, Guangdong518020, People's Republic of China
| | - Xiuwei Li
- Chinese Center for Disease Control and Prevention, National Reference Laboratory for Iodine Deficiency Disorders, Beijing100050, People's Republic of China
| | - Deqian Mao
- Chinese Center for Disease Control and Prevention, National Institute for Nutrition and Health, Beijing100050, People's Republic of China
| | - Yanyan Liu
- Shenzhen Center for Chronic Disease Control, Shenzhen, Guangdong518020, People's Republic of China
| | - Weidong Li
- Chinese Center for Disease Control and Prevention, National Institute for Nutrition and Health, Beijing100050, People's Republic of China
| | - Wei Yu
- Shenzhen Center for Chronic Disease Control, Shenzhen, Guangdong518020, People's Republic of China
| | - Jiaxi Lu
- Chinese Center for Disease Control and Prevention, National Institute for Nutrition and Health, Beijing100050, People's Republic of China
| | - Junan Yan
- Shenzhen Center for Chronic Disease Control, Shenzhen, Guangdong518020, People's Republic of China
| | - Jianhua Piao
- Chinese Center for Disease Control and Prevention, National Institute for Nutrition and Health, Beijing100050, People's Republic of China
| | - Lichen Yang
- Chinese Center for Disease Control and Prevention, National Institute for Nutrition and Health, Beijing100050, People's Republic of China
| | - Chongzheng Guo
- Changzhi Medical College, Changzhi, Shanxi046000, People's Republic of China
| | - Xiaoli Liu
- Shenzhen Center for Chronic Disease Control, Shenzhen, Guangdong518020, People's Republic of China
| | - Xiaoguang Yang
- Chinese Center for Disease Control and Prevention, National Institute for Nutrition and Health, Beijing100050, People's Republic of China
- Shenzhen Center for Chronic Disease Control, Shenzhen, Guangdong518020, People's Republic of China
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Guo W, Yang Y, Jiang W, Cheng Y, Wu W, Pan Z, Zhang D, Li S, Ren Z, Zhang N, Zhang K, Pearce EN, Chen W, Zhang W. An Iodine Balance Study in Chinese School-age Children. J Clin Endocrinol Metab 2023; 108:e949-e955. [PMID: 37146180 DOI: 10.1210/clinem/dgad244] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 04/16/2023] [Accepted: 05/01/2023] [Indexed: 05/07/2023]
Abstract
CONTEXT Few iodine balance studies have been conducted in school-age children. OBJECTIVE This study aimed to conduct an iodine balance study in school-age children. METHODS We measured daily iodine intake, excretion, and retention for 3 consecutive days without any dietary interventions in school-age children. Linear mixed-effects models were used to fit the relationship between total iodine intake and iodine retention. RESULTS 29 children aged 7-12 years (mean age 10.2 ± 1.4 years) with normal thyroid function and thyroid volume were recruited. The 0 balance value (iodine intake = iodine excretion, iodine retention = 0 μg/day) shifted with iodine intake in an iodine sufficient population. The 0 balance value for school-age children with an iodine intake of 235 (133, 401) μg/day is 164 μg/day. Children aged 7-12 years with iodine intake >400 μg/day were almost all in a positive iodine state. CONCLUSION An iodine intake of 235 (133, 401) μg/day for children aged 7-10 years achieved a 0 balance value of 164 μg/day. Long-term iodine intake of >400 μg/day is not recommended.
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Affiliation(s)
- Wenxing Guo
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China
| | - Ying Yang
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China
| | - Wen Jiang
- Department of Iodine Deficiency Disorders, Shandong Provincial Institute for Endemic Disease Control, Jinan, Shandong Province 250014, China
| | - Yuangui Cheng
- Department of General Surgery, People's Hospital of Gaoqing County, Zibo, Shandong Province 256399, China
| | - Wen Wu
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China
| | - Ziyun Pan
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China
| | - Dingyan Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China
| | - Shaohan Li
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China
| | - Zhiyuan Ren
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China
| | - Naifan Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China
| | - Kexin Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China
| | - Elizabeth N Pearce
- Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine, Boston, MA 02118, USA
| | - Wen Chen
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China
| | - Wanqi Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin 300070, China
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
- The Key Laboratory of Hormone and Development (Ministry of Health), Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300070, China
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Chen W, Wang W, Gao M, Chen Y, Guo W, Dong S, Sun H, Pan Z, Pearce EN, Tan L, Shen J, Zhang W. Iodine Intakes of <150 μg/day or >550 μg/day are Not Recommended during Pregnancy: A Balance Study. J Nutr 2023; 153:2041-2050. [PMID: 37100687 DOI: 10.1016/j.tjnut.2022.10.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 09/25/2022] [Accepted: 10/28/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Adequate iodine intake during pregnancy is critical for maintaining maternal and fetal thyroid function and development. There are only limited data from iodine-balance studies to inform iodine requirements during pregnancy. OBJECTIVES This is an iodine-balance study conducted to explore the associations among iodine intake, excretion, and retention to provide information regarding iodine requirements during pregnancy. METHODS A 7-d iodine-balance experiment enrolled 93 healthy pregnant Chinese women from Hebei, Tanjin, and Shandong. Duplicates of all foods and beverages consumed were systematically collected and measured for iodine content. Iodine excretion was measured by collecting 24-h urine and feces samples. Simple linear regression models were used to assess relationships between total iodine intake and iodine retention, whereas mixed effect models were used to assess the relationship between daily iodine intake and iodine retention. RESULTS The mean ± SD age of participating pregnant women was 29 ± 2 y at a median 22 (IQR: 13-30) wk of gestation. The mean 7-d iodine retention was 43.0 ± 1060 μg/7 d. A negative iodine balance was present in 56% of women whereas 44% had a positive balance. Pregnant women with iodine intakes <150 μg/d were in negative balance whereas those with intakes >550 μg/d were in positive balance. The daily iodine intake at zero balance was 343 μg/d, which was higher in women from Shandong (492 μg/d) than in those from Hebei and Tianjin (202 μg/d). CONCLUSIONS Iodine intake at zero balance determined in pregnant women with adequate iodine nutrition is 202 μg/d, and the calculated recommended nutrient intake (RNI) is 280 μg/d. Iodine intakes of <150 μg/d and >550 μg/d are not recommended during pregnancy. This trial was registered at clinicaltrials.gov as NCT03710148.
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Affiliation(s)
- Wen Chen
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China; Department of Endocrinology and Metabolism, Health care and Prevention, Tianjin Medical University General Hospital, Tianjin, China
| | - Wei Wang
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China; The Department of Health Services and Management, School of Management, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Min Gao
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Yanting Chen
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Wenxing Guo
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Shuyao Dong
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Hao Sun
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Ziyun Pan
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Elizabeth N Pearce
- Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine, Boston, MA, USA
| | - Long Tan
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Jun Shen
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Wanqi Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China; Tianjin Key Laboratory of Environment, Nutrition and Public Health, Center for International Collaborative Research on Environment, Nutrition and Public Health, Tianjin, China; Department of Endocrinology and Metabolism, Health care and Prevention, Tianjin Medical University General Hospital, Tianjin, China.
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Li Y, Wang J, Liu X, Li W, Mao D, Lu J, Li X, Tan H, Liu Y, Yan J, Yu W, Guo C, Liu X, Yang X. Re-exploring the requirement of dietary iodine intake in Chinese female adults based on 'iodine overflow theory'. Eur J Nutr 2023; 62:1467-1478. [PMID: 36651989 PMCID: PMC10030447 DOI: 10.1007/s00394-022-03065-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 12/01/2022] [Indexed: 01/19/2023]
Abstract
PURPOSE We re-explored the basal iodine requirement based on healthy Chinese female and a new iodine overflow theory was proposed for iodine balance study. METHODS Thirty-six Chinese healthy female adults (age 20.7 ± 1.1) were recruited for this study, which included 40 days low iodine depletion period and six stages of 30 days supplementation period. Uniform diets with low iodine were provided and the content of iodine in the diet was regulated by dairy products. The total iodine intake from food and the total iodine excretion through 24-h urine and staged feces were completely gathered and monitored. The incremental (Δ) intake and excretion over the range were calculated. RESULTS The iodine intake and excretion were 13.6 μg/day and 48.6 μg/day at the first stage, respectively. The incremental iodine intakes and excretions were 21.1 μg/day to 120.3 μg/day and 25.8 μg/day to 105.4 μg/day for the supplementation stages, respectively. According to the 'iodine overflow theory', the zero iodine balance (Δ iodine intake = Δ iodine excretion) derived from a mixed effect model indicated a mean iodine intake of 52.2 μg/d (1.0 μg/d kg). The RNI for iodine to healthy Chinese female adult was 73.1 μg/d (1.4 μg/d kg). CONCLUSION A daily iodine intake of 52.2 μg/d may meet the basal iodine requirement for healthy Chinese female adults, and Chinese female may need more than 20% iodine intake than male based on the 'iodine overflow theory'. The trial was registered at the Chinese Clinical Trial Registry in May 2018 (No: ChiCTR1800016184).
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Affiliation(s)
- Yajie Li
- Changzhi Medical College, No. 360, Jiefang East Street, Changzhi, 046000, Shanxi, People's Republic of China
| | - Jun Wang
- School of Food and Drug, Shenzhen Polytechnic, Shenzhen, 518055, Guangdong, People's Republic of China
| | - Xiaobing Liu
- Chinese Center for Disease Control and Prevention, National Institute of Nutrition and Health, Key Laboratory of Trace Element Nutrition of National Health Commission, No. 29, Nanwei Road, Beijing, 100050, People's Republic of China
| | - Weidong Li
- Chinese Center for Disease Control and Prevention, National Institute of Nutrition and Health, Key Laboratory of Trace Element Nutrition of National Health Commission, No. 29, Nanwei Road, Beijing, 100050, People's Republic of China
| | - Deqian Mao
- Chinese Center for Disease Control and Prevention, National Institute of Nutrition and Health, Key Laboratory of Trace Element Nutrition of National Health Commission, No. 29, Nanwei Road, Beijing, 100050, People's Republic of China
| | - Jiaxi Lu
- Chinese Center for Disease Control and Prevention, National Institute of Nutrition and Health, Key Laboratory of Trace Element Nutrition of National Health Commission, No. 29, Nanwei Road, Beijing, 100050, People's Republic of China
| | - Xiuwei Li
- National Reference Laboratory for iodine deficiency disorders, Chinese Center for Disease Control and Prevention, Beijing, 100050, People's Republic of China
| | - Hongxing Tan
- Shenzhen Center for Chronic Disease Control, No. 2021, Buxin Road, Shenzhen, 518020, Guangdong, People's Republic of China
| | - Yanyan Liu
- Shenzhen Center for Chronic Disease Control, No. 2021, Buxin Road, Shenzhen, 518020, Guangdong, People's Republic of China
| | - Junan Yan
- Shenzhen Center for Chronic Disease Control, No. 2021, Buxin Road, Shenzhen, 518020, Guangdong, People's Republic of China
| | - Wei Yu
- Shenzhen Center for Chronic Disease Control, No. 2021, Buxin Road, Shenzhen, 518020, Guangdong, People's Republic of China
| | - Chongzheng Guo
- Changzhi Medical College, No. 360, Jiefang East Street, Changzhi, 046000, Shanxi, People's Republic of China
| | - Xiaoli Liu
- Shenzhen Center for Chronic Disease Control, No. 2021, Buxin Road, Shenzhen, 518020, Guangdong, People's Republic of China
| | - Xiaoguang Yang
- Chinese Center for Disease Control and Prevention, National Institute of Nutrition and Health, Key Laboratory of Trace Element Nutrition of National Health Commission, No. 29, Nanwei Road, Beijing, 100050, People's Republic of China.
- Shenzhen Center for Chronic Disease Control, No. 2021, Buxin Road, Shenzhen, 518020, Guangdong, People's Republic of China.
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Infant iodine status and associations with maternal iodine nutrition, breast-feeding status and thyroid function. Br J Nutr 2023; 129:854-863. [PMID: 35535981 PMCID: PMC9975782 DOI: 10.1017/s0007114522001465] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
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, breast-feeding status and thyroid function. In this cohort study, 113 infants were followed up at ages 3, 6 and 11 months in Norway. Infant and maternal urinary iodine concentration (UIC), maternal iodine intake, breast milk iodine concentration (BMIC), breast-feeding status and infant thyroid function tests were measured. The median infant UIC was 82 µg/l at the age of 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 v. 190 µg/l) and 6 months (105 v. 315 µg/l). Neither infant UIC nor BMIC were associated with infant thyroid function tests. 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.
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10
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Estimation of appropriate dietary intake of iodine among lactating women in China based on iodine loss in breast milk. Eur J Nutr 2023; 62:739-748. [PMID: 36209299 DOI: 10.1007/s00394-022-02996-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 08/31/2022] [Indexed: 11/04/2022]
Abstract
OBJECTIVE Data on iodine loss in breast milk, which are critical for establishing the appropriate dietary iodine intake for lactating women, is currently limited. A study was conducted to assess iodine loss in breast milk among Chinese lactating women to estimate the appropriate dietary intake of iodine. METHODS A total of 54 pairs of healthy, lactating women and their infants aged 0-6 months were recruited from Tianjin and Luoyang cities in China. A 4 days infant weighing study was conducted to assess iodine loss in the breast milk of lactating women. Mothers were required to weigh and record their infants' body weights before and after each feeding for a 24 h period from 8:00 am to 8:00 am. During the weighing study, 2812 breast milk samples and 216 24-h urine samples were collected from each lactating mother for four consecutive days. In addition, a 3 days 24 h dietary record, including salt weighing and drinking water samples collecting, was performed by each lactating mother to determine dietary iodine intake during the weighing study. RESULTS The average dietary iodine intake of lactating women was 323 ± 80 μg/d. The median breast milk iodine concentration and 24 h urinary iodine concentration of lactating women were 154 (122-181) and 135 (104-172) μg/L, respectively. The mean volume of breast milk and the mean iodine loss in the breast milk of lactating women were 711 ± 157 mL/d and 112 ± 47 μg/d, respectively. The appropriate dietary intake of iodine among lactating Chinese women is approximately 260 µg/d. CONCLUSIONS Based on the iodine loss in breast milk (110 μg/d) found in this study, and the estimated average requirement of iodine for adults, the appropriate dietary intake of iodine among lactating Chinese women is 260 µg/d, which is higher than the 240 μg/d recommended by the China Nutrition Science Congress in 2013.
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11
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Wang J, Zhang H, Mao D, Tan H, Yu W, Xu J, Hong W, Piao J, Yang L, Liu X, Lu J, Li W, Li Y, Liu X, Yang X. Exploration of the lower threshold of iodine intake in Southern Chinese young adults based on ‘overflow theory’ in an iodine balance study. Nutr J 2022; 21:35. [PMID: 35644684 PMCID: PMC9150309 DOI: 10.1186/s12937-022-00775-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 04/14/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Appropriate iodine intake for adults is essential to reduce the prevalence of thyroid diseases, but there is little research data on iodine requirement of Chinese population. This study aimed to explore the iodine requirement of young adults to maintain a healthy status based on ‘overflow theory’.
Methods
Iodine-balance experiment has been performed in this project. We conducted an 18-day study consisted of a 6-day acclimation period and 3 consecutive experimental stages in 37 Chinese healthy young adults (23 female and 14 male). Each stage was consumed for 4 days. Strictly-controlled low-iodine intake diets were provided for adults in the first period, an egg or 125mL milk was added in the second and third period, respectively. The dietary samples, 24-h urine specimens and faeces of volunteers were collected daily for assessment of iodine intake and excretion in volunteers.
Results
Mean values of iodine intake (22.7±3.6, 35.1±3.7, and 52.2±3.8μg/d), excretion (64.7±13.9, 62.3±12.6, and 94.3±14.5μg/d) and iodine balance (-35.2±19.5, -21.0±19.8, and -33.5±26.9μg/d) were significantly different among three periods for male (P<0.001 for all); mean values of iodine intake (16.6±3.1, 29.7±2.7, and 48.0±2.7μg/d), and excretion (47.0±9.9, 55.5±8.1, and 75.7±12.4μg/d) were significantly different among three periods for female (P < 0.001 for all). No significant difference was observed among the 3 periods for female in the iodine balance (-30.5±9.3, -25.9±7.3, and -27.6±12.1μg/d). The linear regression equation of iodine excretion on iodine intake was Y=0.979X+37.04 (male) and Y=0.895X+31.48 (female). Compared with stage 2, iodine excretion increments in stage 3 had exceeded the iodine intake increment for men. The ratio of increment was 1.675 for male when the average iodine intake was 52.2μg/d in stage 3. When the iodine excretion increment equaled to the iodine intake increment, the daily iodine intake of men was 47.0μg.
Conclusion
We have evaluated the iodine requirement of young adults in southern China based on overflow theory. Our results indicate the lower limit of iodine requirement for Chinese young men is 47.0μg/d. The trial was registered at www.chictr.org.cn as ChiCTR1800014877.
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12
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Abstract
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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Affiliation(s)
- Maria Andersson
- Nutrition Research Unit, University Children’s Hospital Zurich, CH-8032 Zürich, Switzerland
| | - Christian P Braegger
- Nutrition Research Unit, University Children’s Hospital Zurich, CH-8032 Zürich, Switzerland
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13
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Bertinato J, Gaudet J, De Silva N, Mohanty S, Qiao C, Herod M, Gharibeh N, Weiler H. Iodine Status of Mother-Infant Dyads from Montréal, Canada: Secondary Analyses of a Vitamin D Supplementation Trial in Breastfed Infants. J Nutr 2022; 152:1459-1466. [PMID: 35218192 PMCID: PMC9178965 DOI: 10.1093/jn/nxac047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/16/2022] [Accepted: 02/22/2022] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Most pregnant or lactating women in Canada will not meet iodine requirements without iodine supplementation. OBJECTIVES To assess the iodine status of 132 mother-infant pairs based on secondary analyses of a vitamin D supplementation trial in breastfed infants from Montréal, Canada. METHODS Maternal iodine status was assessed using the breastmilk iodine concentration (BMIC). Singleton, term-born infants were studied from 1-36 months of age. Usual (adjusted for within-person variation) iodine intakes were estimated from urinary iodine and creatinine concentrations. Iodine status was assessed using median urinary iodine concentrations (UICs) and by estimating inadequate intakes by the cut-point method using a proposed Estimated Average Requirement for infants 0-6 months of age (72 μg/d). RESULTS At 1, 3, and 6 months of age, 70%, 63%, and 3% of infants, respectively, were exclusively breastfed. From 1-36 months of age (n = 82-129), the median UICs were ≥100 μg/L (range, 246-403 μg/L), which is the cutoff for adequate intakes set by the WHO for children <2 years. Almost all (98%-99%) infants at 1 and 2 months, 2 and 3 months, and 3 and 6 months of age had usual creatinine-adjusted iodine intakes ≥ 72 μg/d. The median BMIC was higher (P < 0.001) at 1 month compared to 6 months of lactation [1 month, 198 μg/kg (IQR, 124-274; n = 105) and 6 months, 109 μg/kg (IQR, 67-168; n = 78)]. At 1 and 6 months, 96% and 79% of mothers, respectively, had a BMIC ≥ 60 μg/kg, the lower limit of a normal reference range. The percentages of mothers that used a multivitamin-mineral (MVM) supplement containing iodine were 90% in pregnancy and 79% and 59% at 1 and 6 months of lactation, respectively. CONCLUSIONS The iodine status of infants was adequate throughout infancy. These results support a recommendation that all women who could become pregnant, who are pregnant, or who are breastfeeding take a daily MVM supplement containing iodine.
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Affiliation(s)
| | - Jeremiah Gaudet
- Nutrition Research Division, Bureau of Nutritional Sciences, HPFB (Health Products and Food Branch), Health Canada, Ottawa, Canada
| | - Nimal De Silva
- Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, Canada
| | - Smitarani Mohanty
- Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, Canada
| | - Cunye Qiao
- Bureau of Food Surveillance and Science Integration, HPFB, Health Canada, Ottawa, Canada
| | - Matthew Herod
- Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, Canada
- Canadian Nuclear Laboratories Regulatory Program Division, Directorate of Nuclear Cycle and Facilities Regulation, Canadian Nuclear Safety Commission, Ottawa, Canada
| | - Nathalie Gharibeh
- Nutrition Research Division, Bureau of Nutritional Sciences, HPFB (Health Products and Food Branch), Health Canada, Ottawa, Canada
- School of Human Nutrition, McGill University, Sainte-Anne-de-Bellevue, Québec, Canada
| | - Hope Weiler
- Nutrition Research Division, Bureau of Nutritional Sciences, HPFB (Health Products and Food Branch), Health Canada, Ottawa, Canada
- School of Human Nutrition, McGill University, Sainte-Anne-de-Bellevue, Québec, Canada
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14
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Abstract
PURPOSE OF REVIEW Iodine deficiency is a global concern, and in recent years, there has been a significant improvement in the number of countries identified as being iodine-sufficient. This review considers the best strategies to ensure iodine sufficiency among breastfeeding women and their infants. RECENT FINDINGS Fortification strategies to improve iodine intake have been adequate for school-age children (SAC); however, often, iodine deficiency remains for breastfeeding women and their infants. Daily supplementation with iodine is not an ideal strategy to overcome deficiency. Countries defined as iodine-sufficient, but where pregnant and breastfeeding women have inadequate intake, should consider increasing salt iodine concentration, such that the median urinary iodine concentration of SAC can be up to 299 µg/L. This will ensure adequate intake for mothers and infants, without SAC being at risk thyroid dysfunction. Consensus is required for thresholds for iodine adequacy for breastfeeding women and infants.
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15
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Jin Y, Coad J, Zhou SJ, Skeaff S, Benn C, Brough L. Use of Iodine Supplements by Breastfeeding Mothers Is Associated with Better Maternal and Infant Iodine Status. Biol Trace Elem Res 2021; 199:2893-2903. [PMID: 33094447 DOI: 10.1007/s12011-020-02438-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 10/11/2020] [Indexed: 12/21/2022]
Abstract
Adequate iodine status during conception, pregnancy and lactation is essential for supporting infant neurodevelopment. Iodine status in adults and children was improved after two New Zealand government initiatives, but the status of breastfeeding women is unknown. This study aimed to investigate the iodine intake and status of lactating mother-infant pairs at 3 months postpartum and to assess maternal iodine knowledge and practice. Iodine intake was estimated by a weighed 4-day diet diary (4DDD). Maternal urinary iodine concentrations (UIC) in spot urine, breast milk iodine concentrations (BMIC) and infant UIC were measured. Questions about iodine-specific knowledge and practice were asked. In 87 breastfeeding mother-infant pairs, maternal iodine intake was 151 (99, 285) μg/day, and 58% had an intake below the estimated average requirement (EAR) of 190 μg/day. Maternal median UIC (MUIC) was 82 (46, 157) μg/L indicating iodine deficiency (i.e., < 100 μg/L). Women who used iodine-containing supplements had a significantly higher MUIC (111 vs 68 μg/L, P = 0.023) and BMIC (84 vs 62 μg/L, P < 0.001) than non-users. Infants fed by women using iodine-containing supplements had a higher MUIC (150 vs 86 μg/L, P = 0.036) than those of non-users. A total of 66% (57/87) of women had no or low iodine knowledge. The iodine knowledge score was a statistically significant predictor of consuming iodine-containing supplements [(beta = 1.321, P = 0.008)]. Despite a decade of initiatives to increase iodine intakes in New Zealand, iodine knowledge was low; iodine intake and status of these lactating women were suboptimal, but women who used iodine-containing supplement were more likely to achieve adequate status.Study Registration Number (Australia and New Zealand Clinical Trials Registry): ACTRN12615001028594.
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Affiliation(s)
- Ying Jin
- School of Health Sciences, College of Health, Massey University, Palmerston North, New Zealand
| | - Jane Coad
- Nutrition Science, School of Food and Advance Technology, College of Sciences, Massey University, Private Bag 11 222, Palmerston North, 4474, New Zealand
| | - Shao J Zhou
- School of Agriculture, Food and Wine, Faculty of Sciences & Robinson Research Institute, University of Adelaide, Adelaide, Australia
| | - Sheila Skeaff
- Department of Human Nutrition, University of Otago, Dunedin, New Zealand
| | - Cheryl Benn
- Mid Central and Whanganui District Health Board, Palmerston North, New Zealand
| | - Louise Brough
- Nutrition Science, School of Food and Advance Technology, College of Sciences, Massey University, Private Bag 11 222, Palmerston North, 4474, New Zealand.
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16
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Siro SS, Baumgartner J, Schoonen M, Ngounda J, Malan L, Symington EA, Smuts CM, Zandberg L. Characterization of Genetic Variants in the SLC5A5 Gene and Associations With Breast Milk Iodine Concentration in Lactating Women of African Descent: The NUPED Study. Front Nutr 2021; 8:692504. [PMID: 34368208 PMCID: PMC8342754 DOI: 10.3389/fnut.2021.692504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 06/22/2021] [Indexed: 11/13/2022] Open
Abstract
Background: The sodium iodide symporter is responsible for the transfer of iodine into breast milk and is encoded for by the SLC5A5 gene. The role of genetic variants in the SLC5A5 gene locus in relation to the transfer of iodine from plasma into breast milk in healthy lactating individuals has, to our knowledge, not been explored. Objective: To identify and characterize possible genetic variants of the SLC5A5 gene in women of African descent living in urban South Africa, and to study associations with breast milk iodine concentrations (BMIC) in lactating women. Methods: This study is affiliated to the Nutrition during Pregnancy and Early Development (NuPED) cohort study (n = 250 enrolled pregnant women). In a randomly selected sub-sample of 32 women, the SLC5A5 gene was sequenced to identify known and novel variants. Of the identified variants, genotyping of selected variants was performed in all pregnant women who gave consent for genetic analyses (n = 246), to determine the frequency of the variants in the study sample. Urinary iodine concentration (UIC) in spot urine samples and BMIC were measured to determine iodine status. Associations of SLC5A5 genetic variants with BMIC were studied in lactating women (n = 55). Results: We identified 27 variants from sequencing of gene exomes and 10 variants were selected for further study. There was a significant difference in BMIC between the genotypes of the rs775249401 variant (P = 0.042), with the homozygous GG group having lower BMIC [86.8 (54.9-167.9) μg/L] compared to the (A) allele carriers rs775249401(AG+AA) [143.9 (122.4-169.3) μg/L] (P = 0.042). Of the rs775249401(GG), 49% had UIC <100 μg/L and 61% had BMIC <100 μg/L. On the other hand, 60% of the rs775249401(AG+AA) carriers had UIC <100 μg/L, and none had a BMIC <100 μg/L. Conclusion: Our results suggest that A-allele carriers of rs775249401(AG+AA) are likely to have higher iodine transfer into breast milk compared to the homozygous GG counterparts. Thus, genetic variations in the SLC5A5 gene may play an important role in the transfer of iodine from plasma into breast milk and may partially explain inter-individual variability in BMIC.
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Affiliation(s)
- Sicelosethu S. Siro
- Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa
| | - Jeannine Baumgartner
- Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa
- Human Nutrition Laboratory, Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Maryke Schoonen
- Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa
| | - Jennifer Ngounda
- Department of Nutrition and Dietetics, University of the Free State, Bloemfontein, South Africa
| | - Linda Malan
- Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa
| | - Elizabeth A. Symington
- Department of Life and Consumer Sciences, University of South Africa, Johannesburg, South Africa
| | - Cornelius M. Smuts
- Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa
| | - Lizelle Zandberg
- Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa
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17
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Bakken KS, Aarsland TE, Groufh-Jacobsen S, Solvik BS, Gjengedal ELF, Henjum S, Strand TA. Adequate Urinary Iodine Concentration among Infants in the Inland Area of Norway. Nutrients 2021; 13:nu13061826. [PMID: 34071905 PMCID: PMC8229746 DOI: 10.3390/nu13061826] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 05/12/2021] [Accepted: 05/25/2021] [Indexed: 11/16/2022] Open
Abstract
Considering the importance of iodine to support optimal growth and neurological development of the brain and central nervous system, this study aimed to assess and evaluate iodine status in Norwegian infants. We collected data on dietary intake of iodine, iodine knowledge in mothers, and assessed iodine concentration in mother’s breast milk and in infant’s urine in a cross-sectional study at two public healthcare clinics in the inland area of Norway. In the 130 mother–infant pairs, the estimated infant 24-h median iodine intake was 50 (IQR 31, 78) µg/day. The median infant urinary iodine concentration (UIC) was 146 (IQR 93, 250) µg/L and within the recommended median defined by the World Health Organization for this age group. Weaned infants had a higher UIC [210 (IQR 130, 330) µg/L] than exclusively breastfed infants [130 (IQR 78, 210) µg/L] and partially breastfed infants [135 (IQR 89, 250) µg/L], which suggest that the dietary data obtained in this study did not capture the accurate iodine intake of the included infants. The iodine status of infants in the inland area of Norway seemed adequate. Weaned infants had higher UIC compared to breastfed infants, suggesting early access and consumption of other sources of iodine in addition to breast milk.
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Affiliation(s)
- Kjersti Sletten Bakken
- Women’s Clinic at Lillehammer Hospital, Innlandet Hospital Trust, 2609 Lillehammer, Norway; (T.E.A.); (B.S.S.)
- Center of International Health, Faculty of Medicine, University of Bergen, P.O. Box 7804, 5020 Bergen, Norway;
- Correspondence: ; Tel.: +47-95-78-13-49
| | - Tonje Eiane Aarsland
- Women’s Clinic at Lillehammer Hospital, Innlandet Hospital Trust, 2609 Lillehammer, Norway; (T.E.A.); (B.S.S.)
- Center of International Health, Faculty of Medicine, University of Bergen, P.O. Box 7804, 5020 Bergen, Norway;
| | - Synne Groufh-Jacobsen
- Department of Nutrition and Public Health, Faculty of Health and Sport Sciences, University of Agder, Universitetsveien 25, 4630 Kristiansand, Norway;
| | - Beate Stokke Solvik
- Women’s Clinic at Lillehammer Hospital, Innlandet Hospital Trust, 2609 Lillehammer, Norway; (T.E.A.); (B.S.S.)
| | - Elin Lovise Folven Gjengedal
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, 1432 Aas, Norway;
| | - Sigrun Henjum
- Department of Nursing and Health Promotion, Faculty of Health Sciences, OsloMet–Oslo Metropolitan University, 0130 Oslo, Norway;
| | - Tor Arne Strand
- Center of International Health, Faculty of Medicine, University of Bergen, P.O. Box 7804, 5020 Bergen, Norway;
- Department of Research, Innlandet Hospital Trust, 2609 Lillehammer, Norway
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Iodine status of postpartum women and their infants aged 3, 6 and 12 months: Mother and Infant Nutrition Investigation (MINI). Br J Nutr 2021; 127:570-579. [PMID: 33858523 DOI: 10.1017/s000711452100129x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
To alleviate the re-emergence of iodine deficiency in New Zealand, two strategies, the mandatory fortification of bread with iodised salt (2009) and a government-subsidised iodine supplement for breast-feeding women (2010), were introduced. Few studies have investigated mother and infant iodine status during the first postpartum year; this study aimed to describe iodine status of mothers and infants at 3, 6 and 12 months postpartum (3MPP, 6MPP and 12MPP, respectively). Partitioning of iodine excretion between urine and breast milk of exclusive breast-feeding (EBF) women at 3MPP was determined. In total, eighty-seven mother-infant pairs participated in the study. Maternal and infant spot urinary iodine concentration (UIC) and breast milk iodine concentration (BMIC) were determined. The percentage of women who took iodine-containing supplements decreased from 46 % at 3MPP to 6 % at 12MPP. Maternal median UIC (MUIC) at 3MPP (82 (46, 157) µg/l), 6MPP (85 (43, 134) µg/l) and 12MPP (95 (51, 169) µg/l) were <100 µg/l. The use of iodine-containing supplements increased MUIC and BMIC only at 3MPP. Median BMIC at all time points were below 75 µg/l. Infant MUIC at 3MPP (115 (69, 182) µg/l) and 6MPP (120 (60, 196) µg/l) were below 125 µg/l. Among EBF women at 3MPP, an increased partitioning of iodine into breast milk (highest proportion 60 %) was shown at lower iodine intakes, along with a reduced fractional iodine excretion in urine (lowest proportion 40 %), indicating a protective mechanism for breastfed infants' iodine status. In conclusion, this cohort of postpartum women was iodine-deficient. Iodine status of their breastfed infants was suboptimal. Lactating women who do not consume iodine-rich foods and those who become pregnant again should take iodine-containing supplements.
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Huang CJ, Cheng CP, Lee LH, Chen HS, Hwu CM, Tang KT, Shih CW, Yeh CC, Yang CC, Wang FF. Iodine nutritional status of lactating women in northern Taiwan in 2019. J Chin Med Assoc 2021; 84:400-404. [PMID: 33595993 DOI: 10.1097/jcma.0000000000000505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Pregnant and lactating women are vulnerable to iodine deficiency. This study was conducted to evaluate the iodine nutritional status of lactating women in northern Taiwan. METHODS Women recruited from Taipei Veterans General Hospital (TVGH) in 2019 provided a spot urine sample and completed a Food Frequency Questionnaire. The urinary iodine concentration (UIC) was measured by inductively coupled plasma mass spectrometry. RESULTS The overall median UIC in 198 women was 120.4 μg/L, indicating a sufficient iodine status. Univariate analysis revealed a lower median UIC in women of younger age (p = 0.004), who were not taking multivitamins (p = 0.004), not on a postpartum nourishment diet (p = 0.04), and whose infant received more breast milk (p = 0.004). The median UIC was <100 μg/L in the group aged 20 to 29 years (UIC: 74.4 μg/L) and in women whose infants' diet was composed of >50% breast milk (UIC: 86.1 μg/L). A postpartum nourishment diet was followed by 73.7% (n = 146) of the women. Nevertheless, a significant decrease in the intake frequency of iodine-containing foods, including seaweeds (p < 0.001), seafood (p < 0.001), dairy products (p = 0.009), and multivitamins (p < 0.001) was observed compared with the intake noted in a previous survey of pregnant women in TVGH. Following multivariate analysis, only younger age (20-29 vs ≥30 years; odds ratio [OR]: 3.38; 95% confidence interval [CI]: 1.49-7.65), no use of multivitamin (OR: 1.89; 95% CI: 1.03-3.48), and infant diet composition (>50% breast milk vs <50% breast milk; OR: 2.93; 95% CI: 1.37-6.25) were independently associated with UIC < 100 μg/L. CONCLUSION The results suggest that the iodine status in lactating women in northern Taiwan is adequate. However, iodine deficiency may continue to be present in certain subgroups, such as women of younger age and those who do not take multivitamins.
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Affiliation(s)
- Chun-Jui Huang
- Division of Endocrinology and Metabolism, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Institute of Public Health, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
| | - Cheng-Pin Cheng
- Division of Endocrinology and Metabolism, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Lin-Hsuan Lee
- Division of Endocrinology and Metabolism, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Institute of Food Safety and Health Risk Assessment, School of Pharmaceutical Science, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
| | - Harn-Shen Chen
- Division of Endocrinology and Metabolism, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
| | - Chii-Min Hwu
- Division of Endocrinology and Metabolism, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
| | - Kam-Tsun Tang
- Division of Endocrinology and Metabolism, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
| | - Chiao-Wei Shih
- Division of Endocrinology and Metabolism, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Chang-Ching Yeh
- Department of Obstetrics & Gynecology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Department of Obstetrics & Gynecology, Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Department of Nurse-Midwifery and Women Health, College of Nursing, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan, ROC
| | - Chen-Chang Yang
- Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Institute of Public Health, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Division of Clinical Toxicology & Occupational Medicine, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Institute of Environmental & Occupational Health Sciences, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
| | - Fan-Fen Wang
- Division of Endocrinology and Metabolism, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Department of Medicine, Yangming Branch, Taipei City Hospital, Taipei, Taiwan, ROC
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20
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Abstract
Both insufficient and excessive maternal iodine consumption can result in congenital hypothyroidism. In East Asian cultures, seaweed is traditionally consumed in high quantities by peripartum women as it is thought to improve lactation. We present a case of transient congenital hypothyroidism due to maternal seaweed consumption at a daily basis during pregnancy and lactation in a Dutch family without Asian background. This case highlights that even in families of non-Asian background, high maternal intake of iodine-rich seaweed occurs and can result in transient or permanent hyperthyrotropinemia in the neonate with risk of impaired neurodevelopmental outcome if untreated.
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Affiliation(s)
- Hester Vlaardingerbroek
- Department of Pediatrics, Subdivision of Endocrinology, Willem Alexander Children's Hospital, LUMC, Leiden, The Netherlands .,Department of Pediatrics, Subdivision of Endocrinology, Sophia Children's Hospital, Erasmus Medical Centre, Rotterdam, The Netherlands
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21
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Eriksen KG, Andersson M, Hunziker S, Zimmermann MB, Moore SE. Effects of an Iodine-Containing Prenatal Multiple Micronutrient on Maternal and Infant Iodine Status and Thyroid Function: A Randomized Trial in The Gambia. Thyroid 2020; 30:1355-1365. [PMID: 32183608 PMCID: PMC7482118 DOI: 10.1089/thy.2019.0789] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Background: Iodine supplementation is recommended to pregnant women in iodine-deficient populations, but the impact in moderate iodine deficiency is uncertain. We assessed the effect of an iodine-containing prenatal multiple micronutrient (MMN) supplement in a rural Gambian population at risk of moderate iodine deficiency. Materials and Methods: This study uses data and samples collected as a part of the randomized controlled trial Early Nutrition and Immune Development (ENID; ISRCTN49285450) conducted in Keneba, The Gambia. Pregnant women (<20 weeks gestation) were randomized to either a daily supplement of MMNs containing 300 μg of iodine or an iron and folic acid (FeFol) supplement. Randomization was double blinded (participants and investigators). The coprimary outcomes were maternal urinary iodine concentration (UIC) and serum thyroglobulin (Tg), assessed at baseline and at 30 weeks' gestation. Secondary outcomes were maternal serum thyrotropin (TSH), total triiodothyronine (TT3), total thyroxine (TT4) (assessed at baseline and at 30 weeks' gestation), breast milk iodine concentration (BMIC) (assessed at 8, 12, and 24 weeks postpartum), infant serum Tg (assessed at birth [cord], 12, and 24 weeks postpartum), and serum TSH (assessed at birth [cord]). The effect of supplementation was evaluated using mixed effects models. Results: A total of 875 pregnant women were enrolled between April 2010 and February 2015. In this secondary analysis, we included women from the MMN (n = 219) and FeFol (n = 219) arm of the ENID trial. At baseline, median (interquartile range or IQR) maternal UIC and Tg was 51 μg/L (33-82) and 22 μg/L (12-39), respectively, indicating moderate iodine deficiency. Maternal MMN supplement increased maternal UIC (p < 0.001), decreased maternal Tg (p < 0.001), and cord blood Tg (p < 0.001) compared with FeFol. Maternal thyroid function tests (TSH, TT3, TT4, and TT3/TT4 ratio) and BMIC did not differ according to maternal supplement group over the course of the study. Median (IQR) BMIC, maternal UIC, and infant Tg in the MMN group were 51 μg/L (35-72), 39 μg/L (25-64), and 87 μg/L (59-127), respectively, at 12 weeks postpartum, and did not differ between supplement groups. Conclusions: Supplementing moderately iodine-deficient women during pregnancy improved maternal iodine status and reduced Tg concentration. However, the effects were not attained postpartum and maternal and infant iodine nutrition remained inadequate during the first six months after birth. Consideration should be given to ensuring adequate maternal status through pregnancy and lactation in populations with moderate deficiency.
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Affiliation(s)
- Kamilla G. Eriksen
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
- Address correspondence to: Kamilla G. Eriksen, PhD, Department of Nutrition, Exercise and Sports, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg, Copenhagen, Denmark
| | - Maria Andersson
- Division of Gastroenterology and Nutrition, Children's Research Centre, University Children's Hospital Zurich, Zurich, Switzerland
| | - Sandra Hunziker
- Human Nutrition Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland
| | - Michael B. Zimmermann
- Human Nutrition Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland
| | - Sophie E. Moore
- Department of Women and Children's Health, King's College London, London, United Kingdom
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22
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An iodine balance study to explore the recommended nutrient intake of iodine in Chinese young adults. Br J Nutr 2020; 124:1156-1165. [PMID: 32624007 DOI: 10.1017/s0007114520002196] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Data on average iodine requirements for the Chinese population are limited following implementation of long-term universal salt iodisation. We explored the minimum iodine requirements of young adults in China using a balance experiment and the 'iodine overflow' hypothesis proposed by our team. Sixty healthy young adults were enrolled to consume a sequential experimental diet containing low, medium and high levels of iodine (about 20, 40 and 60 μg/d, respectively). Each dose was consumed for 4 d, and daily iodine intake, excretion and retention were assessed. All participants were in negative iodine balance throughout the study. Iodine intake, excretion and retention differed among the three iodine levels (P < 0·01 for all groups). The zero-iodine balance derived from a random effect model indicated a mean iodine intake of 102 μg/d, but poor correlation coefficients between observed and predicted iodine excretion (r 0·538 for μg/d data) and retention (r 0·304 for μg/d data). As iodine intake increased from medium to high, all of the increased iodine was excreted ('overflow') through urine and faeces by males, and 89·5 % was excreted by females. Although the high iodine level (63·4 μg/d) might be adequate in males, the corresponding level of 61·6 μg/d in females did not meet optimal requirements. Our findings indicate that a daily iodine intake of approximately half the current recommended nutrient intake (120 μg/d) may satisfy the minimum iodine requirements of young male adults in China, while a similar level is insufficient for females based on the 'iodine overflow' hypothesis.
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23
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Petersen E, Thorisdottir B, Thorsdottir I, Gunnlaugsson G, Arohonka P, Erlund I, Gunnarsdottir I. Iodine status of breastfed infants and their mothers' breast milk iodine concentration. MATERNAL AND CHILD NUTRITION 2020; 16:e12993. [PMID: 32162412 PMCID: PMC7296790 DOI: 10.1111/mcn.12993] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 02/24/2020] [Accepted: 02/26/2020] [Indexed: 12/26/2022]
Abstract
Iodine is an essential nutrient for growth and development during infancy. Data on iodine status of exclusively (EBF) and partially breastfed (PBF) infants as well as breast milk iodine concentration (BMIC) are scarce. We aimed to assess (a) infant iodine nutrition at the age of 5.5 months by measuring urinary iodine concentration (UIC) in EBF (n = 32) and PBF (n = 28) infants and (b) mothers' breast milk iodine concentration (n = 57). Sixty mother–infant pairs from three primary health care centres in Reykjavik and vicinities provided urine and breast milk samples for iodine analysis and information on mothers' habitual diet. The mother–infant pairs were participants of the IceAge2 study, which focuses on factors contributing to infant growth and development, including body composition and breast‐milk energy content. The median (25th–75th percentiles) UIC was 152 (79–239) μg/L, with no significant difference between EBF and PBF infants. The estimated median iodine intake ranged from 52 to 86 μg/day, based on urinary data (assuming an average urine volume of 300–500 ml/day and UIC from the present study). The median (25th–75th percentiles) BMIC was 84 (48–114) μg/L. It is difficult to conclude whether iodine status is adequate in the present study, as no ranges for median UIC reflecting optimal iodine nutrition exist for infants. However, the results add important information to the relatively sparse literature on UIC, BMIC, and iodine intake of breastfed infants.
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Affiliation(s)
- Erna Petersen
- Department of Clinical Nutrition, Landspitali University Hospital, Reykjavik, Iceland.,Unit for Nutrition Research, Faculty of Food Science and Nutrition, Landspitali University Hospital, University of Iceland, Reykjavik, Iceland
| | - Birna Thorisdottir
- Unit for Nutrition Research, Faculty of Food Science and Nutrition, Landspitali University Hospital, University of Iceland, Reykjavik, Iceland
| | - Inga Thorsdottir
- School of Health Sciences, University of Iceland, Reykjavik, Iceland
| | - Geir Gunnlaugsson
- Faculty of Sociology, Anthropology and Folkloristics, School of Social Sciences, University of Iceland, Reykjavik, Iceland
| | - Petra Arohonka
- Forensic Toxicology Unit, Biochemistry Laboratory, Finnish Institute for Health and Welfare (THL), Helsinki, Finland
| | - Iris Erlund
- Forensic Toxicology Unit, Biochemistry Laboratory, Finnish Institute for Health and Welfare (THL), Helsinki, Finland
| | - Ingibjörg Gunnarsdottir
- Department of Clinical Nutrition, Landspitali University Hospital, Reykjavik, Iceland.,Unit for Nutrition Research, Faculty of Food Science and Nutrition, Landspitali University Hospital, University of Iceland, Reykjavik, Iceland
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24
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Groufh-Jacobsen S, Mosand LM, Oma I, Sletten Bakken K, Stokke Solvik B, Lovise Folven Gjengedal E, Brantsæter AL, Strand TA, Henjum S. Mild to Moderate Iodine Deficiency and Inadequate Iodine Intake in Lactating Women in the Inland Area of Norway. Nutrients 2020; 12:E630. [PMID: 32120975 PMCID: PMC7146631 DOI: 10.3390/nu12030630] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/19/2020] [Accepted: 02/25/2020] [Indexed: 12/14/2022] Open
Abstract
Breastfed infants are dependent on an adequate supply of iodine in human milk for the production of thyroid hormones, necessary for development of the brain. Despite the importance of iodine for infant health, data on Norwegian lactating women are scarce. We measured iodine intake and evaluated iodine status and iodine knowledge among lactating women. From October to December 2018, 133 mother-infant pairs were recruited in a cross-sectional study through two public health care centers in Lillehammer and Gjøvik. Each of the women provided two human milk specimens, which were pooled, and one urine sample for analysis of iodine concentration. We used 24-hour dietary recall and food frequency questionnaire (FFQ) to estimate short-term and habitual iodine intake from food and supplements. The median (P25, P75) human milk iodine concentration (HMIC) was 71 (45, 127) µg/L-of which, 66% had HMIC <100 µg/L. The median (P25, P75) urinary iodine concentration (UIC) was 80 µg/L (52, 141). The mean (± SD) 24-hour iodine intake and habitual intake was 78 ± 79 µg/day and 75 ± 73 µg/day, respectively. In conclusion, this study confirms inadequate iodine intake and insufficient iodine status among lactating women in the inland area of Norway and medium knowledge awareness about iodine.
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Affiliation(s)
- Synne Groufh-Jacobsen
- Department of Research, Innlandet Hospital Trust, 2629 Lillehammer, Norway;
- Department of Nursing and Health Promotion, Faculty of Health Sciences, OsloMet–Oslo Metropolitan University, 0130 Oslo, Norway;
| | - Lise Mette Mosand
- Department of Clinical Medicine, University of Oslo, 0450 Oslo, Norway;
- Department of Medical Microbiology, Innlandet Hospital Trust, 2629 Lillehammer, Norway;
| | - Ingvild Oma
- Department of Medical Microbiology, Innlandet Hospital Trust, 2629 Lillehammer, Norway;
| | - Kjersti Sletten Bakken
- Women’s Clinic at Lillehammer Hospital, Innlandet Hospital Trust, 2629 Lillehammer, Norway; (K.S.B.); (B.S.S.)
| | - Beate Stokke Solvik
- Women’s Clinic at Lillehammer Hospital, Innlandet Hospital Trust, 2629 Lillehammer, Norway; (K.S.B.); (B.S.S.)
| | - Elin Lovise Folven Gjengedal
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, 1432 Aas, Norway;
| | - Anne Lise Brantsæter
- Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, 0213 Oslo, Norway;
| | - Tor Arne Strand
- Department of Research, Innlandet Hospital Trust, 2629 Lillehammer, Norway;
| | - Sigrun Henjum
- Department of Nursing and Health Promotion, Faculty of Health Sciences, OsloMet–Oslo Metropolitan University, 0130 Oslo, Norway;
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25
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Ellsworth L, McCaffery H, Harman E, Abbott J, Gregg B. Breast Milk Iodine Concentration Is Associated with Infant Growth, Independent of Maternal Weight. Nutrients 2020; 12:E358. [PMID: 32019065 PMCID: PMC7071233 DOI: 10.3390/nu12020358] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/26/2020] [Accepted: 01/27/2020] [Indexed: 12/22/2022] Open
Abstract
In breastfed infants, human milk provides the primary source of iodine to meet demands during this vulnerable period of growth and development. Iodine is a key micronutrient that plays an essential role in hormone synthesis. Despite the importance of iodine, there is limited understanding of the maternal factors that influence milk iodine content and how milk iodine intake during infancy is related to postnatal growth. We examined breast milk samples from near 2 weeks and 2 months post-partum in a mother-infant dyad cohort of mothers with pre-pregnancy weight status defined by body mass index (BMI). Normal (NW, BMI < 25.0 kg/m2) is compared to overweight/obesity (OW/OB, BMI ≥ 25.0 kg/m2). The milk iodine concentration was determined by inductively coupled plasma mass spectrometry. We evaluated the associations between iodine content at 2 weeks and infant anthropometrics over the first year of life using multivariable linear mixed modeling. Iodine concentrations generally decreased from 2 weeks to 2 months. We observed no significant difference in iodine based on maternal weight. A higher iodine concentration at 2 weeks was associated with a larger increase in infant weight-for-age and weight-for-length Z-score change per month from 2 weeks to 1 year. This pilot study shows that early iodine intake may influence infant growth trajectory independent of maternal pre-pregnancy weight status.
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Affiliation(s)
- Lindsay Ellsworth
- Division of Neonatal-Perinatal Medicine, Department of Pediatrics, University of Michigan, Ann Arbor, MI 48109, USA;
| | - Harlan McCaffery
- Center for Human Growth and Development, University of Michigan, Ann Arbor, MI 48109, USA;
| | - Emma Harman
- School of Public Health, University of Michigan, Ann Arbor, MI 48109, USA;
| | - Jillian Abbott
- Metals Laboratory, Division of Clinical Biochemistry and Immunology, Mayo Clinic, Rochester, MN 55905, USA;
| | - Brigid Gregg
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Michigan, Ann Arbor, MI 48109, USA
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26
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Chen Y, Gao M, Bai Y, Hao Y, Chen W, Cui T, Guo W, Pan Z, Lin L, Wang C, Shen J, Zhang W. Variation of iodine concentration in breast milk and urine in exclusively breastfeeding women and their infants during the first 24 wk after childbirth. Nutrition 2019; 71:110599. [PMID: 31901706 DOI: 10.1016/j.nut.2019.110599] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 09/15/2019] [Accepted: 09/19/2019] [Indexed: 10/25/2022]
Abstract
OBJECTIVE The aim of this study was to observe the variation of iodine concentration in breast milk and urine in exclusively breastfeeding women and their infants during the first 24 wk after childbirth. METHODS In all, 634 exclusively breastfeeding mother-infant pairs were enrolled at hospital and followed at the 1, 4, 8, 12, 16, and 24 wk postpartum. Spot infant urinary iodine concentration (I-UIC), maternal urinary iodine concentration UIC (M-UIC), and breast milk iodine concentration (BMIC) in bilateral breasts were measured. RESULTS During the first 24 wk, the median I-UIC was 216 (139-362) and 122 (68-217) μg/L in lactating mothers, both indicating iodine sufficiency. A strong correlation and no difference were found between BMIC in bilateral breasts. The mean BMIC (M-BMIC) of the two breasts was 165 (112-257) μg/L with a Bland-Altman index of 2.1%. Positive correlations were found between M-BMIC and I-UIC (r = 0.353, P < 0.001), between M-BMIC and M-UIC (r = 0.339, P < 0.001), and between I-UIC and M-UIC (r = 0.222, P < 0.001). M-BMIC was significantly higher than M-UIC (P < 0.001) and lower than I-UIC (P < 0.001). M-BMIC declined from week 1 to week 8 postpartum, both I-UIC and M-UIC dropped from week 1 to week 4 postpartum and stabilized thereafter. CONCLUSION The iodine nutrition in lactating women and infants were adequate during the first 24 wk after childbirth. M-BMIC declined from week 1 to week 8 postpartum. Both I-UIC and M-UIC dropped from week 1 to week 4 postpartum. Further studies are needed to explore a more definitive BMIC and UIC range for an optimal iodine status in lactating women and breastfed infants.
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Affiliation(s)
- Yanting Chen
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Min Gao
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Yanbo Bai
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Yunmeng Hao
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Wen Chen
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Tingkai Cui
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Wenxing Guo
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Ziyun Pan
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Laixiang Lin
- The Key Laboratory of Hormone and Development (Ministry of Health), Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Chongdan Wang
- Department of Obstetrics and Inpatient, Tanggu Maternity Hospital, Tianjin, China
| | - Jun Shen
- Department of Sanitary Chemistry, School of Public Health, Tianjin Medical University, Tianjin, China.
| | - Wanqi Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Tianjin Medical University, Tianjin, China; The Key Laboratory of Hormone and Development (Ministry of Health), Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China; Department of Endocrinology, Tianjin Medical University General Hospital, Tianjin, China.
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27
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van der Reijden OL, Galetti V, Bürki S, Zeder C, Krzystek A, Haldimann M, Berard J, Zimmermann MB, Herter-Aeberli I. Iodine bioavailability from cow milk: a randomized, crossover balance study in healthy iodine-replete adults. Am J Clin Nutr 2019; 110:102-110. [PMID: 31788697 DOI: 10.1093/ajcn/nqz092] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 04/19/2019] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Milk and dairy products are considered important dietary sources of iodine in many countries. However, to our knowledge, iodine bioavailability from milk has not been directly measured in humans. OBJECTIVE The aim of this study was to compare iodine bioavailability in iodine-replete adults from: 1) cow milk containing a high concentration of native iodine; 2) milk containing a low concentration of native iodine, with the addition of potassium iodide (KI) to assess a potential matrix effect; and 3) an aqueous solution of KI as a comparator; with all 3 containing equal amounts of total iodine (263 µg/250 mL). We also speciated iodine in milk. DESIGN We conducted a 3-wk, randomized, crossover balance study in adults (n = 12) consuming directly analyzed, standardized diets. During the 3 test conditions - high intrinsic iodine milk (IIM), extrinsically added iodine in milk (EIM), and aqueous iodine solution (AIS) - subjects collected 24-h urine over 3 d and consumed the test drink on the second day, with 3- or 4-d wash-out periods prior to each treatment. Iodine absorption was calculated as the ratio of urinary iodine excretion (UIE) to total iodine intake. Milk iodine speciation was performed using ion chromatography-mass spectrometry. RESULTS Iodine intake from the standardized diet was 195 ± 6 µg/d for males and 107 ± 6 µg/d for females; the test drinks provided an additional 263 µg. Eleven subjects completed the protocol. There was a linear relation between iodine intake and UIE (β = 0.89, SE = 0.04, P < 0.001). There were no significant differences in UIE among the 3 conditions (P = 0.24). Median (range) fractional iodine absorption across the 3 conditions was 91 (51-145), 72 (48-95), and 98 (51-143)% on days 1, 2, and 3, respectively, with day 2 significantly lower compared with days 1 and 3 (P < 0.001). In milk, 80-93% of the total iodine was inorganic iodide. CONCLUSION Nearly all of the iodine in cow milk is iodide and although fractional iodine absorption from milk decreases with increasing dose, its bioavailability is high. The trial was registered at clinicaltrials.gov as NCT03590431.
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Affiliation(s)
- Olivia L van der Reijden
- ETH Zurich, Institute of Food, Nutrition and Health, Laboratory of Human Nutrition, Zurich, Switzerland
| | - Valeria Galetti
- ETH Zurich, Institute of Food, Nutrition and Health, Laboratory of Human Nutrition, Zurich, Switzerland
| | - Sarah Bürki
- ETH Zurich, Institute of Food, Nutrition and Health, Laboratory of Human Nutrition, Zurich, Switzerland
| | - Christophe Zeder
- ETH Zurich, Institute of Food, Nutrition and Health, Laboratory of Human Nutrition, Zurich, Switzerland
| | - Adam Krzystek
- ETH Zurich, Institute of Food, Nutrition and Health, Laboratory of Human Nutrition, Zurich, Switzerland
| | - Max Haldimann
- Federal Food Safety and Veterinary Office, Division of Risk Assessment, Bern, Switzerland
| | - Joel Berard
- ETH Zurich, AgroVet-Strickhof, Lindau, Switzerland
| | - Michael B Zimmermann
- ETH Zurich, Institute of Food, Nutrition and Health, Laboratory of Human Nutrition, Zurich, Switzerland
| | - Isabelle Herter-Aeberli
- ETH Zurich, Institute of Food, Nutrition and Health, Laboratory of Human Nutrition, Zurich, Switzerland
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28
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Iodine-fortified toddler milk improves dietary iodine intakes and iodine status in toddlers: a randomised controlled trial. Eur J Nutr 2019; 59:909-919. [PMID: 30929067 DOI: 10.1007/s00394-019-01950-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 03/18/2019] [Indexed: 10/27/2022]
Abstract
PURPOSE We aimed to evaluate the effectiveness of consuming iodine-fortified toddler milk for improving dietary iodine intakes and biochemical iodine status in toddlers. METHODS In a 20-week parallel randomised controlled trial, healthy 12-20-month-old children were assigned to: Fortified Milk [n = 45; iodine-fortified (21.1 µg iodine/100 g prepared drink) cow's milk], or Non-Fortified Milk (n = 90; non-fortified cow's milk). Food and nutrient intakes were assessed with 3-day weighed food records at baseline, and weeks 4 and 20. Urinary iodine concentration (UIC) was measured at baseline and 20 weeks. RESULTS At baseline, toddlers' median milk intake was 429 g/day. There was no evidence that milk intakes changed within or between the groups during the intervention. Toddlers' baseline geometric mean iodine intake was 46.9 µg/day, and the median UIC of 43 µg/L in the Fortified Milk group and 55 µg/L in the Non-Fortified Milk group indicated moderate and mild iodine deficiency, respectively, with this difference due to chance. During the intervention, iodine intakes increased by 136% (p < 0.001) and UIC increased by 85 µg/L (p < 0.001) in the Fortified Milk group compared to the Non-Fortified Milk group. The 20-week median UIC was 91 µg/L in the Fortified Milk group and 49 µg/L in the Non-Fortified Milk group. CONCLUSIONS Consumption of ≈ 1.7 cups of iodine-fortified toddler milk per day for 20 weeks can increase dietary iodine intakes and UIC in healthy iodine-deficient toddlers. This strategy alone is unlikely to provide sufficient intake to ensure adequate iodine status in toddlers at risk of mild-to-moderate iodine deficiency.
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29
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Fallah R, Du L, Braverman LE, He X, Segura-Harrison M, Yeh MW, Pearce EN, Chiu HK, Mittelman SD, Leung AM. Iodine Nutrition in Weaning Infants in the United States. Thyroid 2019; 29:573-576. [PMID: 30827204 PMCID: PMC6457884 DOI: 10.1089/thy.2018.0102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
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.
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Affiliation(s)
- Roja Fallah
- Division of Pediatric Endocrinology, Department of Pediatrics; UCLA David Geffen School of Medicine, Los Angeles, California
| | - Lin Du
- Department of Biostatistics, UCLA Fielding School of Public Health, Los Angeles, California
| | - Lewis E. Braverman
- Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine, Boston, Massachusetts
| | - Xuemei He
- Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine, Boston, Massachusetts
| | - Miriam Segura-Harrison
- Department of Family Medicine, Memorial Hospital of Rhode Island, Brown University, Pawtucket, Rhode Island
| | - Michael W. Yeh
- Section of Endocrine Surgery, Department of Surgery; UCLA David Geffen School of Medicine, Los Angeles, California
| | - Elizabeth N. Pearce
- Division of Endocrinology, Diabetes, and Metabolism; UCLA David Geffen School of Medicine, Los Angeles, California
| | - Harvey K. Chiu
- Division of Pediatric Endocrinology, Department of Pediatrics; UCLA David Geffen School of Medicine, Los Angeles, California
| | - Steven D. Mittelman
- Division of Pediatric Endocrinology, Department of Pediatrics; UCLA David Geffen School of Medicine, Los Angeles, California
| | - Angela M. Leung
- Division of Endocrinology, Diabetes, and Metabolism; UCLA David Geffen School of Medicine, Los Angeles, California
- Address correspondence to: Angela M. Leung, MD, MSc, Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, UCLA David Geffen School of Medicine, VA Greater Los Angeles Healthcare System, 11301 Wilshire Blvd (111D), Los Angeles, CA 90073
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Santos JAR, Christoforou A, Trieu K, McKenzie BL, Downs S, Billot L, Webster J, Li M. Iodine fortification of foods and condiments, other than salt, for preventing iodine deficiency disorders. Cochrane Database Syst Rev 2019; 2:CD010734. [PMID: 30746700 PMCID: PMC6370918 DOI: 10.1002/14651858.cd010734.pub2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Iodine deficiency disorders (IDD) affect close to 1.9 billion people worldwide, and are a major public health concern in many countries. Among children, iodine deficiency is the main cause of potentially preventable deficits of central nervous system development and impairment of cognitive function, as well as goitre and hypothyroidism in people of all ages. Salt iodisation is the preferred strategy for IDD prevention and control, however, in some instances where salt is not the major condiment, alternate vehicles for iodine fortification have been considered. OBJECTIVES To assess the effects of fortifying foods, beverages, condiments, or seasonings other than salt with iodine alone or in conjunction with other micronutrients, on iodine status and health-related outcomes in all populations. SEARCH METHODS Studies were identified through systematic searches of the following databases from their start date to January 2018: Cochrane Public Health Group Specialised Register; CENTRAL; MEDLINE; MEDLINE in Process; Embase; Web of Science; CINAHL; POPLINE; AGRICOLA; BIOSIS; Food Science and Technology Abstracts; OpenGrey; Bibliomap and TRoPHI; AGRIS; IBECS; Scielo; Global Index Medicus-AFRO and EMRO; LILACS; PAHO; WHOLIS; WPRO; IMSEAR; IndMED; and Native Health Research Database. We also searched reference list of relevant articles, conference proceedings, and databases of ongoing trials, and contacted experts and relevant organisations to identify any unpublished work. We applied no language or date restrictions. SELECTION CRITERIA Studies were eligible if they were randomised or quasi-randomised controlled trials (RCT) with randomisation at either the individual or cluster level (including cross-over trials), non-randomised RCTs, or prospective observational studies with a control group, such as cohort studies, controlled before-and-after studies, and interrupted time series. We included studies that examined the effects of fortification of food, beverage, condiment, or seasoning with iodine alone, or in combination with other micronutrients versus the same unfortified food, or no intervention. We considered the following measures: death (all-cause), goitre, physical development, mental development, cognitive function and motor skill development, cretinism, hypothyroidism, adverse effects (any reported by trialists), urinary iodine concentration, thyroid-stimulating hormone (TSH) concentration, and serum thyroglobulin concentration. We included all populations, including pregnant women, from any country. DATA COLLECTION AND ANALYSIS Two review authors independently assessed study eligibility, extracted data, and assessed risk of bias of included studies.We used random-effects meta-analyses to combine data and generate an overall estimate of treatment effect, when more than one study examined the same outcome measure. The overall effect estimate was calculated as the mean difference (MD) or standardised mean difference (SMD) between the intervention group and the comparison group for continuous outcomes, and as odds ratio (OR) for dichotomous outcomes. We assessed the level of heterogeneity through the I² statistic. We conducted post-hoc subgroup analyses to explore possible sources of heterogeneity, and sensitivity analyses to check the robustness of the findings from the primary analyses. We assessed the quality of the evidence for each outcome using the GRADE framework.Where it was not possible to pool the results in a meta-analysis, we provided a narrative summary of the outcomes. MAIN RESULTS Eleven studies met the criteria, providing 14 comparisons, and capturing data on 4317 participants. Seven studies were RCTs, three were cluster non-RCTs, and one was a randomised cross-over design. Seven studies were carried out among school children (N = 3636), three among women of reproductive age (N = 648), and one among infants (N = 33). The studies used diverse types of food as vehicle for iodine delivery: biscuits, milk, fish sauce, drinking water, yoghourt, fruit beverage, seasoning powder, and infant formula milk. Daily amounts of iodine provided ranged from 35 µg/day to 220 µg/day; trial duration ranged from 11 days to 48 weeks. Five studies examined the effect of iodine fortification alone, two against the same unfortified food, and three against no intervention. Six studies evaluated the effect of cofortification of iodine with other micronutrients versus the same food without iodine but with different levels of other micronutrients. We assessed one study to be at low risk of bias for all bias domains, three at low risk of bias for all domains apart from selective reporting, and seven at an overall rating of high risk of bias.No study assessed the primary outcomes of death, mental development, cognitive function, cretinism, or hypothyroidism, or secondary outcomes of TSH or serum thyroglobulin concentration. Two studies reported the effects on goitre, one on physical development measures, and one on adverse effects. All studies assessed urinary iodine concentration.The effects of iodine fortification compared to control on goitre prevalence (OR 1.60, 95% CI 0.60 to 4.31; 1 non-RCT, 83 participants; very low-quality evidence), and five physical development measures were uncertain (1 non-RCT, 83 participants; very low-quality evidence): weight (MD 0.23 kg, 95% CI -6.30 to 6.77); height (MD -0.66 cm, 95% CI -4.64 to 3.33); weight-for-age (MD 0.05, 95% CI -0.59 to 0.69); height-for-age (MD -0.30, 95% CI -0.75 to 0.15); and weight-for-height (MD -0.21, 95% CI -0.51 to 0.10). One study reported that there were no adverse events observed during the cross-over trial (low-quality evidence).Pooled results from RCTs showed that urinary iodine concentration significantly increased following iodine fortification (SMD 0.59, 95% CI 0.37 to 0.81; 6 RCTs, 2032 participants; moderate-quality evidence). This is equivalent to an increase of 38.32 µg/L (95% CI 24.03 to 52.61 µg/L). This effect was not observed in the meta-analysis of non-RCTs (SMD 0.25, 95% CI -0.16 to 0.66; 3 non-RCTs, 262 participants; very low-quality evidence). Sensitivity analyses did not change the effect observed in the primary analyses. AUTHORS' CONCLUSIONS The evidence on the effect of iodine fortification of foods, beverages, condiments, or seasonings other than salt on reducing goitre, improving physical development measures, and any adverse effects is uncertain. However, our findings suggest that the intervention likely increases urinary iodine concentration. Additional, adequately powered, high-quality studies on the effects of iodine fortification of foods on these, and other important outcomes, as well as its efficacy and safety, are required.
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Affiliation(s)
- Joseph Alvin R Santos
- The George Institute for Global Health, University of New South WalesOffice of the Chief ScientistSydneyAustralia
| | | | - Kathy Trieu
- The George Institute for Global Health, University of New South WalesOffice of the Chief ScientistSydneyAustralia
| | - Briar L McKenzie
- The George Institute for Global Health, University of New South WalesOffice of the Chief ScientistSydneyAustralia
| | - Shauna Downs
- Rutgers School of Public HealthDepartment of Health Systems and PolicyNew BrunswickNJUSA
| | - Laurent Billot
- The George Institute for Global Health, University of New South WalesOffice of the Chief ScientistSydneyAustralia
| | - Jacqui Webster
- The George Institute for Global Health, University of New South WalesOffice of the Chief ScientistSydneyAustralia
| | - Mu Li
- The University of SydneySydney School of Public HealthLevel 10, King George V Building RPA. 83‐117 Missenden RoadCamperdownNSWAustralia2050
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Farebrother J, Zimmermann MB, Assey V, Castro MC, Cherkaoui M, Fingerhut R, Jia Q, Jukic T, Makokha A, San Luis TO, Wegmüller R, Andersson M. Thyroglobulin Is Markedly Elevated in 6- to 24-Month-Old Infants at Both Low and High Iodine Intakes and Suggests a Narrow Optimal Iodine Intake Range. Thyroid 2019; 29:268-277. [PMID: 30648484 DOI: 10.1089/thy.2018.0321] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND In areas with incomplete salt iodization coverage, infants and children aged 6-24 months weaning from breast milk and receiving complementary foods are at risk of iodine deficiency. However, few data exist on the risk of excessive iodine intake in this age group. Thyroglobulin (Tg) is a sensitive marker of iodine intake in school-age children and adults and may be used to estimate the optimal iodine intake range in infancy. The aim of this study was to assess the association of low and high iodine intakes with Tg and thyroid function in weaning infants. METHODS This multicenter cross-sectional study recruited infants aged 6-24 months (n = 1543; Mage = 12.2 ± 4.6 months) receiving breast milk with complementary foods, from seven countries in areas with previously documented deficient, sufficient, or excessive iodine intake in schoolchildren or pregnant women. Urinary iodine concentration (UIC) and Tg, total thyroxine, and thyrotropin were measured using dried blood spot testing. RESULTS Median UIC ranged from 48 μg/L (interquartile range 31-79 μg/L) to 552 μg/L (interquartile range 272-987 μg/L) across the study sites. Median Tg using dried blood spot testing was high (>50 μg/L) at estimated habitual iodine intakes <50 μg/day and >230 μg/day. Prevalence of overt thyroid disorders was low (<3%). Yet, subclinical hyperthyroidism was observed in the countries with the lowest iodine intake. CONCLUSIONS Tg is a sensitive biomarker of iodine intake in 6- to 24-month-old infants and follows a U-shaped relationship with iodine intake, suggesting a relatively narrow optimal intake range. Infants with low iodine intake may be at increased risk of subclinical thyroid dysfunction. In population monitoring of iodine deficiency or excess, assessment of iodine status using UIC and Tg may be valuable in this young age group.
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Affiliation(s)
- Jessica Farebrother
- 1 Human Nutrition Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Switzerland
| | - Michael B Zimmermann
- 1 Human Nutrition Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Switzerland
- 2 Iodine Global Network, Ottawa, Ottawa, Canada
| | - Vincent Assey
- 2 Iodine Global Network, Ottawa, Ottawa, Canada
- 3 Nutrition Services Section, Preventive Services Department; Ministry of Health, Community Development, Gender, Elderly, and Children, Dar es Salaam, Tanzania
| | | | - Mohamed Cherkaoui
- 5 Faculté des Sciences Semlalia, Université Caddi Ayyed, Marrakech, Morocco
| | - Ralph Fingerhut
- 6 Swiss Newborn Screening Laboratory and Children's Research Center; University Children's Hospital Zurich, Zurich, Switzerland
| | - Qingzhen Jia
- 7 Shanxi Institute for Prevention and Treatment of Endemic Disease, Linfen, P.R. China
| | - Tomislav Jukic
- 8 Department of Nuclear Medicine and Oncology, Sestre Milosrdnice University Hospital Center and School of Medicine, University of Zagreb, Zagreb, Croatia
- 9 Faculty of Medicine Osijek, University Josip Juraj Strossmayer Osijek, Osijek, Croatia
| | - Anselimo Makokha
- 10 Department of Food Science, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - Theofilo O San Luis
- 2 Iodine Global Network, Ottawa, Ottawa, Canada
- 11 St Luke's Medical Center, Quezon City, Manila, The Philippines
| | - Rita Wegmüller
- 12 Medical Research Council The Gambia, Keneba, The Gambia
| | - Maria Andersson
- 1 Human Nutrition Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Switzerland
- 2 Iodine Global Network, Ottawa, Ottawa, Canada
- 13 Division of Gastroenterology and Nutrition; University Children's Hospital Zurich, Zurich, Switzerland
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Exploration of the appropriate recommended nutrient intake of iodine in healthy Chinese women: an iodine balance experiment. Br J Nutr 2018; 121:519-528. [DOI: 10.1017/s0007114518003653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractThere is a dearth of data on the iodine balance studies of Chinese population. In the present study, we aimed to explore the appropriate recommended nutrient intake (RNI) of iodine based on healthy Chinese women. A 4-week study was conducted in twenty-five Chinese euthyroid women. Uniform diets with different iodine contents were provided in two different periods, in which non-iodised salt was given in the first 3 weeks, followed by 1 week of iodised salt administration. The total iodine intake from diet, water and air as well as the total iodine excretion through urine, faeces and respiration were monitored and determined. The sweat iodine loss was also considered. Moreover, the regression curve model was established between the 24 h iodine intake and 24 h iodine excretion. The 24 h iodine intake in the two periods was 194·8 (sd 62·9) and 487·1 (sd 177·3) μg/d, respectively. The 24 h iodine excretion was 130·9 (sd 39·5) and 265·4 (sd 71·8) μg/d, respectively. Both 24 h iodine intake and 24 h iodine excretion of the two periods were significantly different (all P<0·05). The iodised salt contributed approximately 62·7 % of the total daily iodine intake. Moreover, 92·3 % (277/300) of samples were in positive balance, while twenty-three cases were in negative balance. Our data show that the estimated average requirement for iodine was 110·5 μg/d. Therefore, the RNI for iodine to non-pregnant, non-lactating Chinese women was 154·7 μg/d.
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Nazeri P, Tahmasebinejad Z, Mehrabi Y, Hedayati M, Mirmiran P, Azizi F. Lactating Mothers and Infants Residing in an Area with an Effective Salt Iodization Program Have No Need for Iodine Supplements: Results from a Double-Blind, Placebo-Controlled, Randomized Controlled Trial. Thyroid 2018; 28:1547-1558. [PMID: 30272528 DOI: 10.1089/thy.2018.0153] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND The necessity of iodine supplementation in lactating mothers residing in countries with sustained salt iodization programs for iodine sufficiency of breast-fed infants remains unclear. The aims of this study were to investigate the effect of iodine supplementation on iodine status and growth parameters of lactating mothers and breast-fed infants and to compare these data with that of formula-feeding mothers and their infants during the first year of infancy. METHODS In this multicenter, double-blinded, randomized clinical trial conducted in four healthcare centers in Tehran (Iran), healthy lactating mothers and their term newborns aged 3-5 days were randomly assigned to treatment groups: placebo, 150 μg/day iodine, or 300 μg/day iodine. They were followed up for 12 months. Formula-fed infants aged 30-45 days and their mothers were randomly selected from the same centers. The primary outcomes were maternal and infant urinary iodine concentrations (UICs), breast-milk iodine concentrations (BMICs), and infant growth parameters, measured at 1, 2, 4, 6, 9, and 12 months during routine health visits. The formula-fed group was assessed at 2, 4, 6, 9, and 12 months of age. Analysis was by per protocol principle using mixed-effects models. RESULTS Mother-newborn pairs (n = 180) in treatment groups and partially/exclusively formula-feeding mother-infant pairs (n = 60) participated between October 2014 and January 2016. Median baseline UICs in the treatment groups were 84 μg/L (interquartile range [IQR] 41-143 μg/L) in mothers and 208 μg/L (IQR 91-310 μg/L) in their infants. The values in the formula-fed group were 76 μg/L (IQR 40-144 μg/L) in mothers and 121 μg/L (IQR 66-243 μg/L) in infants. The 300 μg/day iodine group showed significantly higher UICs and BMICs than did the other treatment groups; infant UICs in the 150 μg/day iodine, placebo, and formula-fed groups were similar. Infants in all groups showed iodine sufficiency (median UIC ≥100 μg/L) throughout the study period. Anthropometric measurements were similar between the treatment and formula-fed groups over the study period, except at the last follow-up visit at 12 months. CONCLUSION Supplementation of breast-feeding mothers with either 300 or 150 μg/day iodine improved their iodine status. However, the iodine status of infants in all groups studied indicated iodine sufficiency during the first year of infancy, demonstrating that in countries with effective salt iodization program, iodine supplementation for lactating mothers is unnecessary.
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Affiliation(s)
- Pantea Nazeri
- 1 Family Health Institute, Breastfeeding Research Center, Tehran University of Medical Sciences , Tehran, Iran
- 2 Nutrition and Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences , Tehran, Iran
| | - Zhale Tahmasebinejad
- 2 Nutrition and Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences , Tehran, Iran
| | - Yadollah Mehrabi
- 3 Department of Epidemiology, School of Public Health, Shahid Beheshti University of Medical Sciences , Tehran, Iran
| | - Mehdi Hedayati
- 4 Cellular and Molecular Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences , Tehran, Iran
| | - Parvin Mirmiran
- 2 Nutrition and Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences , Tehran, Iran
| | - Fereidoun Azizi
- 5 Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences , Tehran, Iran
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Hamby T, Kunnel N, Dallas JS, Wilson DP. Maternal iodine excess: an uncommon cause of acquired neonatal hypothyroidism. J Pediatr Endocrinol Metab 2018; 31:1061-1064. [PMID: 30052521 DOI: 10.1515/jpem-2018-0138] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 06/28/2018] [Indexed: 11/15/2022]
Abstract
Background Excessive iodine exposure is an often overlooked cause of neonatal hypothyroidism. Case presentation We present an infant with iodine-induced hypothyroidism, which was detected at age 15 days by newborn screening. The infant's iodine excess resulted from maternal intake of seaweed soup both during and after pregnancy. Treatment included discontinuation of seaweed soup, temporary interruption of breastfeeding and short-term levothyroxine therapy. By age 4 months, the infant's hypothyroidism had resolved, and her growth and development were normal. Conclusions This case illustrates the importance of considering excess dietary iodine as a possible cause of hypothyroidism in infants.
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Affiliation(s)
- Tyler Hamby
- Department of Research Operations, Cook Children's Medical Center, 801 7th Ave., Fort Worth, TX 76104, USA.,Texas College of Osteopathic Medicine, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Nayana Kunnel
- Department of Psychiatry, John Peter Smith Health Network, Fort Worth, TX, USA
| | - John S Dallas
- Department of Pediatric Endocrinology and Diabetes, Cook Children's Medical Center, Fort Worth, TX, USA
| | - Don P Wilson
- Department of Pediatric Endocrinology and Diabetes, Cook Children's Medical Center, Fort Worth, TX, USA
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Abstract
Because infants are born with small amounts of stored intrathyroidal iodine, they depend on human-milk iodine for normal physical and neurologic growth and development. The mammary gland concentrates iodide; however, there is a lack of consensus on the concentrations of breast-milk iodine necessary to achieve equilibrium in the infant. The objectives of the present review are to consider trends in breast-milk iodine concentrations over the course of lactation, to determine which maternal factors or interventions influence breast-milk iodine concentrations, to examine the association between breast-milk iodine concentrations and infant iodine status, and to identify how newer data contribute to the literature and inform recommendations for achieving optimal breast-milk iodine concentrations. A systematic search of the published literature was undertaken by using the US National Library of Medicine's MEDLINE/PubMed bibliographic search engine. Observational and intervention studies were included if the research was original, the study had not been included in a previous review, and iodine concentration in human milk was measured at ≥1 time point during the first 12 mo of lactation. Results of the systematic review indicate that breast-milk iodine concentrations vary widely between populations but are highest in colostrum and decrease gradually throughout the lactation period. Included studies did not replicate earlier findings of an inverse correlation between breast-milk iodine and perchlorate concentrations. Supplementation with high-dose or daily iodine during lactation was effective in increasing breast-milk iodine concentrations with some evidence of a dose-response relationship, which is consistent with findings of earlier supplementation trials in pregnancy and lactation. Although additional and globally representative research is needed, data suggest that breast-milk iodine concentrations in the range of 150 μg/L during the first 6 mo of lactation would achieve or exceed infant iodine equilibrium and prevent the developmental consequences of iodine deficiency.
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Affiliation(s)
- Daphna K Dror
- US Department of Agriculture, Agricultural Research Service, Western Human Nutrition Research Center, Davis, CA
| | - Lindsay H Allen
- US Department of Agriculture, Agricultural Research Service, Western Human Nutrition Research Center, Davis, CA
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Dold S, Zimmermann MB, Jukic T, Kusic Z, Jia Q, Sang Z, Quirino A, San Luis TOL, Fingerhut R, Kupka R, Timmer A, Garrett GS, Andersson M. Universal Salt Iodization Provides Sufficient Dietary Iodine to Achieve Adequate Iodine Nutrition during the First 1000 Days: A Cross-Sectional Multicenter Study. J Nutr 2018; 148:587-598. [PMID: 29659964 DOI: 10.1093/jn/nxy015] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 01/16/2018] [Indexed: 12/14/2022] Open
Abstract
Background Dietary iodine requirements are high during pregnancy, lactation, and infancy, making women and infants vulnerable to iodine deficiency. Universal salt iodization (USI) has been remarkably successful for preventing iodine deficiency in the general population, but it is uncertain if USI provides adequate iodine intakes during the first 1000 d. Objective We set out to assess if USI provides sufficient dietary iodine to meet the iodine requirements and achieve adequate iodine nutrition in all vulnerable population groups. Methods We conducted an international, cross-sectional, multicenter study in 3 study sites with mandatory USI legislation. We enrolled 5860 participants from 6 population groups (school-age children, nonpregnant nonlactating women of reproductive age, pregnant women, lactating women, 0-6-mo-old infants, and 7-24-mo-old infants) and assessed iodine status [urinary iodine concentration (UIC)] and thyroid function in Linfen, China (n = 2408), Tuguegarao, the Philippines (n = 2512), and Zagreb, Croatia (n = 940). We analyzed the iodine concentration in household salt, breast milk, drinking water, and cow's milk. Results The salt iodine concentration was low (<15 mg/kg) in 2.7%, 33.6%, and 3.1%, adequate (15-40 mg/kg) in 96.3%, 48.4%, and 96.4%, and high (>40 mg/kg) in 1.0%, 18.0%, and 0.5% of household salt samples in Linfen (n = 402), Tuguegarao (n = 1003), and Zagreb (n = 195), respectively. The median UIC showed adequate iodine nutrition in all population groups, except for excessive iodine intake in school-age children in the Philippines and borderline low intake in pregnant women in Croatia. Conclusions Salt iodization at ∼25 mg/kg that covers a high proportion of the total amount of salt consumed supplies sufficient dietary iodine to ensure adequate iodine nutrition in all population groups, although intakes may be borderline low during pregnancy. Large variations in salt iodine concentrations increase the risk for both low and high iodine intakes. Strict monitoring of the national salt iodization program is therefore essential for optimal iodine nutrition. This trial was registered at clinicaltrials.gov as NCT02196337.
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Affiliation(s)
- Susanne Dold
- Human Nutrition Laboratory, Institute of Food Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Michael B Zimmermann
- Human Nutrition Laboratory, Institute of Food Nutrition and Health, ETH Zurich, Zurich, Switzerland.,Iodine Global Network, Ottawa, Ontario, Canada
| | - Tomislav Jukic
- Department of Nuclear Medicine and Oncology, Sestre Milosrdnice University Hospital Centre and School of Medicine, University of Zagreb, Zagreb, Croatia.,Faculty of Medicine Osijek, University Josip Juraj Strossmayer Osijek, Osijek, Croatia
| | - Zvonko Kusic
- Department of Nuclear Medicine and Oncology, Sestre Milosrdnice University Hospital Centre and School of Medicine, University of Zagreb, Zagreb, Croatia.,Croatian Academy of Sciences and Arts, Zagreb, Croatia
| | - Qingzhen Jia
- Shanxi Institute for Prevention and Treatment of Endemic Disease, Linfen, China
| | - Zhongna Sang
- Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Antonio Quirino
- Technological Institute of the Philippines, Manila, Philippines
| | | | - Ralph Fingerhut
- Swiss Newborn Screening Laboratory, Division of Metabolism and Children's Research Centre (CRC), University Children's Hospital Zurich, Zurich, Switzerland
| | | | - Arnold Timmer
- Global Alliance for Improved Nutrition (GAIN), Geneva, Switzerland
| | - Greg S Garrett
- Global Alliance for Improved Nutrition (GAIN), Geneva, Switzerland
| | - Maria Andersson
- Human Nutrition Laboratory, Institute of Food Nutrition and Health, ETH Zurich, Zurich, Switzerland.,Iodine Global Network, Ottawa, Ontario, Canada
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Iodine status of postpartum women and their infants in Australia after the introduction of mandatory iodine fortification. Br J Nutr 2017; 117:1656-1662. [PMID: 28789730 DOI: 10.1017/s0007114517001775] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Mandatory I fortification in bread was introduced in Australia in 2009 in response to the re-emergence of biochemical I deficiency based on median urinary I concentration (UIC)<100 µg/l. Data on the I status of lactating mothers and their infants in Australia are scarce. The primary aim of this study was to assess the I status, determined by UIC and breast milk I concentration (BMIC), of breast-feeding mothers in South Australia and UIC of their infants. The secondary aim was to assess the relationship between the I status of mothers and their infants. The median UIC of the mothers (n 686) was 125 (interquartile range (IQR) 76-200) µg/l and median BMIC (n 538) was 127 (IQR 84-184) µg/l. In all, 38 and 36 % of the mothers had a UIC and BMIC below 100 µg/l, respectively. The median UIC of infants (n 628) was 198 (IQR 121-296) µg/l, and 17 % had UIC<100 µg/l. Infant UIC was positively associated with maternal UIC (β 0·26; 95 % CI 0·14, 0·37, P<0·001) and BMIC (β 0·85; 95 % CI 0·66, 1·04, P<0·001) at 3 months postpartum after adjustment for gestational age, parity, maternal secondary and further education, BMI category and infant feeding mode. The adjusted OR for infant UIC<100 µg/l was 6·49 (95 % CI 3·80, 11·08, P<0·001) in mothers with BMIC<100 µg/l compared with those with BMIC≥100 µg/l. The I status of mothers and breast-fed infants in South Australia, following mandatory I fortification, is indicative of I sufficiency. BMIC<100 µg/l increased the risk of biochemical I deficiency in breast-fed infants.
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Henjum S, Lilleengen AM, Aakre I, Dudareva A, Gjengedal ELF, Meltzer HM, Brantsæter AL. Suboptimal Iodine Concentration in Breastmilk and Inadequate Iodine Intake among Lactating Women in Norway. Nutrients 2017; 9:E643. [PMID: 28640217 PMCID: PMC5537763 DOI: 10.3390/nu9070643] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 06/15/2017] [Accepted: 06/17/2017] [Indexed: 11/24/2022] Open
Abstract
Breastfed infants depend on sufficient maternal iodine intake for optimal growth and neurological development. Despite this, few studies have assessed iodine concentrations in human milk and there is currently no published data on iodine status among lactating women in Norway. The aim of this study was to assess iodine concentrations in breast milk (BMIC) in lactating women and estimate iodine intake. Five Mother and Child Health Centres in Oslo were randomly selected during 2016, and 175 lactating women between 2nd and 28th weeks postpartum participated. Each of the women provided four breastmilk samples which were pooled and analysed for iodine concentrations. Participants also provided information on iodine intake from food and supplements covering the last 24 h and the habitual iodine intake (food frequency questionnaire). The median (p25, p75 percentiles) BMIC was 68 (45, 98) µg/L and 76% had BMIC <100 µg/L. Only 19% had taken an iodine-containing supplement during the last 24 h. The median 24 h iodine intake from food (p25, p75) was 121 (82, 162) µg/day and the total intake (food and supplements) was 134 (95, 222) µg/day. The majority of lactating women had suboptimal BMIC and inadequate intake of iodine from food and supplements.
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Affiliation(s)
- Sigrun Henjum
- Department of Nursing and Health Promotion, Faculty of Health Sciences, Oslo and Akershus University, College of Applied Sciences, Oslo 0310, Norway.
| | - Anne Marie Lilleengen
- Department of Nursing and Health Promotion, Faculty of Health Sciences, Oslo and Akershus University, College of Applied Sciences, Oslo 0310, Norway.
| | - Inger Aakre
- Department of Nursing and Health Promotion, Faculty of Health Sciences, Oslo and Akershus University, College of Applied Sciences, Oslo 0310, Norway.
| | - Anna Dudareva
- Department of Nursing and Health Promotion, Faculty of Health Sciences, Oslo and Akershus University, College of Applied Sciences, Oslo 0310, Norway.
| | - Elin Lovise Folven Gjengedal
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Aas 1433, Norway.
| | - Helle Margrete Meltzer
- Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo 0403, Norway.
| | - Anne Lise Brantsæter
- Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo 0403, Norway.
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Dold S, Zimmermann MB, Aboussad A, Cherkaoui M, Jia Q, Jukic T, Kusic Z, Quirino A, Sang Z, San Luis TO, Vandea E, Andersson M. Breast Milk Iodine Concentration Is a More Accurate Biomarker of Iodine Status Than Urinary Iodine Concentration in Exclusively Breastfeeding Women. J Nutr 2017; 147:528-537. [PMID: 28228508 DOI: 10.3945/jn.116.242560] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/06/2016] [Accepted: 01/23/2017] [Indexed: 11/14/2022] Open
Abstract
Background: Iodine status in populations is usually assessed by the median urinary iodine concentration (UIC). However, iodine is also excreted in breast milk during lactation; thus, breast milk iodine concentration (BMIC) may be a promising biomarker of iodine nutrition in lactating women. Whether the mammary gland can vary fractional uptake of circulating iodine in response to changes in dietary intake is unclear.Objective: We evaluated UIC and BMIC as biomarkers for iodine status in lactating women with a wide range of iodine intakes.Methods: We recruited 866 pairs of lactating mothers and exclusively breastfed infants from 3 iodine-sufficient study sites: Linfen, China (n = 386); Tuguegarao, Philippines (n = 371); and Zagreb, Croatia (n = 109). We also recruited iodine-deficient lactating women from Amizmiz, Morocco (n = 117). We collected urine and breast milk samples and measured UIC and BMIC.Results: In the 3 iodine-sufficient sites, a pooled regression analysis of the estimated iodine excretion revealed higher fractional iodine excretion in breast milk than in urine at borderline low iodine intakes. In contrast, in the iodine-deficient site in Morocco, a constant proportion (∼33%) of total iodine was excreted into breast milk.Conclusions: In iodine-sufficient populations, when iodine intake in lactating women is low, there is increased partitioning of iodine into breast milk. For this reason, maternal UIC alone may not reflect iodine status, and BMIC should also be measured to assess iodine status in lactating women. Our data suggest a BMIC reference range (2.5th and 97.5th percentiles) of 60-465 μg/kg in exclusively breastfeeding women. This trial was registered at clinicaltrials.gov as NCT02196337.
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Affiliation(s)
- Susanne Dold
- Human Nutrition Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland;
| | - Michael B Zimmermann
- Human Nutrition Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland.,Iodine Global Network, Ottawa, Canada
| | | | - Mohamed Cherkaoui
- Laboratory of Human Ecology, Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakesh, Morocco
| | - Qingzhen Jia
- Shanxi Institute for Prevention and Treatment of Endemic Disease, Linfen, China
| | - Tomislav Jukic
- Department of Nuclear Medicine and Oncology, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Zvonko Kusic
- Department of Nuclear Medicine and Oncology, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Antonio Quirino
- St. Luke's Medical Center, Quezon City, Manila, Philippines; and
| | - Zhongna Sang
- Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | | | - Elena Vandea
- Human Nutrition Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Maria Andersson
- Human Nutrition Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland.,Iodine Global Network, Ottawa, Canada
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