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Bath SC. Thyroid function and iodine intake: global recommendations and relevant dietary trends. Nat Rev Endocrinol 2024; 20:474-486. [PMID: 38693274 DOI: 10.1038/s41574-024-00983-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/20/2024] [Indexed: 05/03/2024]
Abstract
Iodine is a micronutrient that is essential for thyroid hormone production. Adequate iodine intake is especially important during pregnancy and early life, when brain development is dependent on thyroid hormones. Iodine intake recommendations vary around the world, but most recommendations generally reflect the increased requirements during pregnancy and lactation, although adequate iodine intake before pregnancy is also important. Tremendous progress has been made in improving iodine intake across the world over the past 30 years, mainly through salt-iodization programmes. However, in countries without strong iodine fortification programmes, and with shifts in dietary patterns, a need has arisen for health organizations, governments and clinicians to ensure that adequate iodine is consumed by everyone in the population. For example, in countries in which adequate iodine intake depends on individual food choice, particularly of iodine-rich milk and dairy products, intake can be highly variable and is also vulnerable to changing dietary patterns. In this Review, iodine is considered in the wider context of the increasing prevalence of overweight and obesity, the dietary trends for salt restriction for cardiovascular health and the increasing uptake of plant-based diets.
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Affiliation(s)
- Sarah C Bath
- Department of Nutrition, Food and Exercise Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK.
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Willemse JP, Smits LJ, Braat MM, Meertens LJ, van Montfort P, van Dongen MC, Ellerbrock J, van Dooren IM, Duvekot EJ, Zwaan IM, Spaanderman ME, Scheepers HC. Counseling pregnant women on calcium: effects on calcium intake. J Perinat Med 2023; 51:346-355. [PMID: 35998889 PMCID: PMC10010736 DOI: 10.1515/jpm-2021-0376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 07/29/2022] [Indexed: 11/15/2022]
Abstract
OBJECTIVES To evaluate the effect of incorporating calcium advice into early pregnancy counseling on calcium intake during pregnancy in the Netherlands. METHODS A multicenter prospective before-after cohort study was conducted introducing risk-based care including calculating individual pre-eclampsia risk. Part of the intervention was to incorporate calcium advice into routine counseling. We calculated individual daily calcium intake and adequacy of calcium intake (≥1,000 mg/day) at 16, 24 and 34 weeks of pregnancy. We performed a multiple logistic regression adjusting for covariates to identify any differences in the risk of inadequate calcium intake between RC and CAC. RESULTS In regular care (RC, 2013-2015, n=2,477) 60% had inadequate calcium intake, compared to 49% during calcium advice care (CAC, 2017-2018, n=774) (aOR 0.75, 95% CI 0.64-0.88). Specific calcium supplements were used by 2% and 29% in RC and CAC, respectively (OR 25.1, 95% CI 17.8-36.0). Determinants of an inadequate calcium intake were lower age (aOR per additional year 0.96, 95% CI: 0.94-0.98), nulliparity (aOR 1.22, 95% CI: 1.03-1.45) and non-Caucasian origin (aOR 1.83, 95% CI 1.09-3.09). In CAC, risk of inadequate intake decreased with increasing predicted pre-eclampsia risk, which was a trend reversal compared to RC. CONCLUSIONS Incorporating calcium advice into early pregnancy counseling was shown to lead to a decrease in the risk of inadequate calcium intake during pregnancy, but still inadequate intake in half of the women suggesting the need for further study on improving implementation. Awareness of individual increased PE risk had positive effect on calcium intake.
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Affiliation(s)
- Jessica P.M.M. Willemse
- Department of Epidemiology, CAPHRI Care and Public Health Research Institute, Maastricht UniversityMaastricht, The Netherlands
| | - Luc J.M. Smits
- Department of Epidemiology, CAPHRI Care and Public Health Research Institute, Maastricht UniversityMaastricht, The Netherlands
| | | | - Linda J.E. Meertens
- Department of Epidemiology, CAPHRI Care and Public Health Research Institute, Maastricht UniversityMaastricht, The Netherlands
| | - Pim van Montfort
- Department of Epidemiology, CAPHRI Care and Public Health Research Institute, Maastricht UniversityMaastricht, The Netherlands
| | - Martien C. van Dongen
- Department of Epidemiology, CAPHRI Care and Public Health Research Institute, Maastricht UniversityMaastricht, The Netherlands
| | - Jonas Ellerbrock
- Department of Obstetrics & Gynaecology, Zuyderland Medical CentreHeerlen, The Netherlands
| | - Ivo M.A. van Dooren
- Department of Obstetrics and Gynaecology, Sint Jans Gasthuis WeertWeert, The Netherlands
| | - Ella. J. Duvekot
- Department of Obstetrics and Gynaecology, VieCuri Medical CentreVenlo, The Netherlands
| | - Iris M. Zwaan
- Department of Obstetrics and Gynaecology, Laurentius Medical CentreRoermond, The Netherlands
| | - Marc E.A. Spaanderman
- Department of Obstetrics and Gynaecology, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Hubertina C.J. Scheepers
- Department of Obstetrics and Gynaecology, Maastricht University Medical Centre, Maastricht, The Netherlands
- Grow, school for oncology and developmental biology, Maastricht University, Maastricht, The Netherlands
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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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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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Dietary Choices of New Zealand Women during Pregnancy and Lactation. Nutrients 2020; 12:nu12092692. [PMID: 32899261 PMCID: PMC7551142 DOI: 10.3390/nu12092692] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/25/2020] [Accepted: 08/28/2020] [Indexed: 11/17/2022] Open
Abstract
Dietary recommendations during pregnancy and lactation have become increasingly complex, and sources of information more numerous but not always reliable, potentially causing confusion and unsafe choices. Women were recruited during pregnancy or within six months postpartum and completed questionnaires on dietary choices, food safety, and sources of nutrition information. Women (n = 458) from around New Zealand participated in the study. They consumed a wide range of foods and beverages and reported various dietary changes. In pregnancy, women commonly avoided alcohol (92%), raw milk products (86%), and raw, smoked, or pre-cooked seafood and fish (84%), and made changes due to food safety concerns. Influential advice was acquired from a range of sources including midwives (37%) and the New Zealand pregnancy and breastfeeding guidelines (25%) during pregnancy. Food avoidance was less common in lactation. However, fewer women consumed milk products during lactation (64%) than pregnancy (93%). Potentially unreliable sources were used more frequently in lactation including alternative health practitioners (26%) and family or friends (12%), and dietary changes were often made in response to infant symptoms without supporting evidence. This study highlighted a need for good communication of evidence-based recommendations to women, especially during lactation.
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Karaçil Ermumcu MŞ, Mengi Çelik Ö, Acar Tek N. An Evaluation of Awareness, Knowledge, and Use of Folic Acid and Dietary Folate Intake among Non-Pregnant Women of Childbearing Age and Pregnant Women: A Cross-Sectional Study from Turkey. Ecol Food Nutr 2020; 60:101-115. [PMID: 32856479 DOI: 10.1080/03670244.2020.1807344] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This study was carried out to evaluate awareness, knowledge, and use of folic acid and dietary folate intake among non-pregnant women of childbearing age and pregnant women. A cross-sectional study was completed with 1442 women (1106 non-pregnant and 336 pregnant) in Ankara, Turkey. The individuals' awareness, knowledge, and use of folic acid were questioned and food consumption were taken. More than two-thirds of the non-pregnant and pregnant women had heard of folic acid (77.2% and 89.0%, respectively). The pregnant women (53.9%) knew more that folic acid should be used before conception in order to prevent congenital anomalies than non-pregnant women (41.4%). It was found that 70.2% of the pregnant women and only 15.1% of the non-pregnant women used folic acid supplementation. The pregnant women (1368.4 mcg; 330.4 mcg) significantly had higher folic acid and dietary folate intake than non-pregnant women (29.6 mcg; 289.3 mcg) (p < .01). Despite many public health campaigns, awareness, knowledge, and appropriate use of folic acid are still inadequate and not at the desired level in women of childbearing age.
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Affiliation(s)
| | - Özge Mengi Çelik
- Faculty of Health Sciences, Department of Nutrition and Dietetics, Gazi University , Ankara, Turkey
| | - Nilüfer Acar Tek
- Faculty of Health Sciences, Department of Nutrition and Dietetics, Gazi University , Ankara, Turkey
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Sztal-Mazer S. Letter to the Editor: "Association of Maternal Iodine Status With Child IQ: A Meta-Analysis of Individual-Participant Data". J Clin Endocrinol Metab 2019; 104:6116-6117. [PMID: 31314088 DOI: 10.1210/jc.2019-01407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 07/11/2019] [Indexed: 11/19/2022]
Affiliation(s)
- Shoshana Sztal-Mazer
- Department of Endocrinology and Diabetes, Alfred Health, Melbourne, Victoria, Australia
- Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Women's Health Research Program, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
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Cooray SD, Langston-Cox AG, Robinson PJ, Bahemia N, Davis SR, Bell RJ, Topliss DJ, Schneider HG, Sztal-Mazer S. Awareness and use of iodine supplementation among Australian women attending a low-risk pregnancy clinic. Aust N Z J Obstet Gynaecol 2018; 58:E16-E17. [PMID: 30306556 DOI: 10.1111/ajo.12829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 04/24/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Shamil D Cooray
- Department of Endocrinology and Diabetes, Alfred Health, Melbourne, Victoria, Australia
| | | | - Penelope J Robinson
- Women's Health Research Program, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Nasreen Bahemia
- Rural Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Susan R Davis
- Department of Endocrinology and Diabetes, Alfred Health, Melbourne, Victoria, Australia.,Women's Health Research Program, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Robin J Bell
- Women's Health Research Program, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Duncan J Topliss
- Department of Endocrinology and Diabetes, Alfred Health, Melbourne, Victoria, Australia.,Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Hans G Schneider
- Department of Endocrinology and Diabetes, Alfred Health, Melbourne, Victoria, Australia.,School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.,Alfred Pathology Service, Alfred Health, Melbourne, Victoria, Australia
| | - Shoshana Sztal-Mazer
- Department of Endocrinology and Diabetes, Alfred Health, Melbourne, Victoria, Australia.,Central Clinical School, Monash University, Melbourne, Victoria, Australia.,Women's Health Research Program, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
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Development of Databases on Iodine in Foods and Dietary Supplements. Nutrients 2018; 10:nu10010100. [PMID: 29342090 PMCID: PMC5793328 DOI: 10.3390/nu10010100] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 01/09/2018] [Accepted: 01/10/2018] [Indexed: 01/02/2023] Open
Abstract
Iodine is an essential micronutrient required for normal growth and neurodevelopment; thus, an adequate intake of iodine is particularly important for pregnant and lactating women, and throughout childhood. Low levels of iodine in the soil and groundwater are common in many parts of the world, often leading to diets that are low in iodine. Widespread salt iodization has eradicated severe iodine deficiency, but mild-to-moderate deficiency is still prevalent even in many developed countries. To understand patterns of iodine intake and to develop strategies for improving intake, it is important to characterize all sources of dietary iodine, and national databases on the iodine content of major dietary contributors (including foods, beverages, water, salts, and supplements) provide a key information resource. This paper discusses the importance of well-constructed databases on the iodine content of foods, beverages, and dietary supplements; the availability of iodine databases worldwide; and factors related to variability in iodine content that should be considered when developing such databases. We also describe current efforts in iodine database development in the United States, the use of iodine composition data to develop food fortification policies in New Zealand, and how iodine content databases might be used when considering the iodine intake and status of individuals and populations.
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