Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Review Article
  • Published:

Thyroid function and iodine intake: global recommendations and relevant dietary trends

Nature Reviews Endocrinology (2024)Cite this article

Subjects

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.

Key points

  • Despite progress since the 1990s, iodine deficiency remains a public health concern across the world, particularly in pregnancy and early life.

  • Severe iodine deficiency is now less common than in the past, but mild-to-moderate deficiency during pregnancy might have consequences for the developing fetus, including on neurodevelopmental outcomes.

  • Iodized salt programmes have been a successful way of improving iodine intake in many countries, but with a focus on salt-reduction campaigns, there is potential for reduced intake of iodized salt, and so reduced iodine intake, although both policies can work together.

  • Animal foods, such as milk and dairy products, provide a considerable proportion of iodine intake in many countries, but with a shift towards a predominantly plant-based diet, iodine intake might be compromised unless consideration is given to ensure adequate iodine intake from suitable sources.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Model showing the risk of iodine deficiency according to dietary patterns.
Fig. 2: Iodine content of a predominantly plant-based diet and a vegan diet.

Similar content being viewed by others

References

  1. Zimmermann, M. B. Iodine deficiency. Endocr. Rev. 30, 376–408 (2009).

    Article  CAS  PubMed  Google Scholar 

  2. Gorstein, J. L., Bagriansky, J., Pearce, E. N., Kupka, R. & Zimmermann, M. B. Estimating the health and economic benefits of universal salt iodization programs to correct iodine deficiency disorders. Thyroid 30, 1802–1809 (2020).

    Article  PubMed  PubMed Central  Google Scholar 

  3. Zimmermann, M. B. The remarkable impact of iodisation programmes on global public health. Proc. Nutr. Soc. 82, 113–119 (2022).

    Article  PubMed  Google Scholar 

  4. Verkaik-Kloosterman, J., van‘t Veer, P. & Ocke, M. C. Simulation model accurately estimates total dietary iodine intake. J. Nutr. 139, 1419–1425 (2009).

    Article  CAS  PubMed  Google Scholar 

  5. WHO. Obesity and overweight. who.int https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight (2024).

  6. Willett, W. et al. Food in the anthropocene: the EAT-Lancet commission on healthy diets from sustainable food systems. Lancet 393, 447–492 (2019).

    Article  PubMed  Google Scholar 

  7. Zimmermann, M. B. & Andersson, M. Assessment of iodine nutrition in populations: past, present, and future. Nutr. Rev. 70, 553–570 (2012).

    Article  PubMed  Google Scholar 

  8. WHO, UNICEF & ICCIDD. Assessment of iodine deficiency disorders and monitoring their elimination. who.int https://www.who.int/publications/i/item/9789241595827 (2007).

  9. Iodine Global Network. Global Scorecard of Iodine Nutrition in 2021. ign.org https://ign.org/scorecard/ (2021).

  10. Zimmermann, M. B. & Andersson, M. GLOBAL ENDOCRINOLOGY: global perspectives in endocrinology: coverage of iodized salt programs and iodine status in 2020. Eur. J. Endocrinol. 185, R13–R21 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  11. Rohner, F. et al. Biomarkers of nutrition for development-iodine review. J. Nutr. 144, 1322S–1342S (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  12. Beckford, K. et al. A systematic review and meta-analysis of 24-h urinary output of children and adolescents: impact on the assessment of iodine status using urinary biomarkers. Eur. J. Nutr. 59, 3113–3131 (2019).

    Article  PubMed  PubMed Central  Google Scholar 

  13. Burns, R., O’Herlihy, C. & Smyth, P. P. The placenta as a compensatory iodine storage organ. Thyroid 21, 541–546 (2011).

    Article  CAS  PubMed  Google Scholar 

  14. Neven, K. Y. et al. Variability of iodine concentrations in the human placenta. Sci. Rep. 10, 161 (2020).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  15. Stilwell, G. et al. The influence of gestational stage on urinary iodine excretion in pregnancy. J. Clin. Endocrinol. Metab. 93, 1737–1742 (2008).

    Article  CAS  PubMed  Google Scholar 

  16. Knudsen, N., Christiansen, E., Brandt-Christensen, M., Nygaard, B. & Perrild, H. Age- and sex-adjusted iodine/creatinine ratio. A new standard in epidemiological surveys? Evaluation of three different estimates of iodine excretion based on casual urine samples and comparison to 24 h values. Eur. J. Clin. Nutr. 54, 361–363 (2000).

    Article  CAS  PubMed  Google Scholar 

  17. Arns-Glaser, L. et al. Estimating habitual iodine intake and prevalence of inadequacy from spot urine in cross-sectional studies: a modeling analysis to determine the required sample size. Am. J. Clin. Nutr. 117, 1270–1277 (2023).

    Article  CAS  PubMed  Google Scholar 

  18. Pearce, E. N. & Caldwell, K. L. Urinary iodine, thyroid function, and thyroglobulin as biomarkers of iodine status. Am. J. Clin. Nutr. 104, 898S–901S (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  19. Bingham, S. A. Limitations of the various methods for collecting dietary intake data. Ann. Nutr. Metab. 35, 117–127 (1991).

    Article  CAS  PubMed  Google Scholar 

  20. Ershow, A. G. et al. Databases of iodine content of foods and dietary supplements-availability of new and updated resources. J. Acad. Nutr. Dietetics 122, 1229–1231 (2022).

    Article  Google Scholar 

  21. Nicol, K. et al. Iodine fortification of plant-based dairy and fish alternatives: the effect of substitution on iodine intake based on a market survey in the UK. Br. J. Nutr. 129, 832–842 (2023).

    Article  CAS  PubMed  Google Scholar 

  22. Food and Nutrition Board Institute of Medicine. Dietary reference intakes for vitamin A, vitamin K, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium and zinc (National Academy Press, 2001).

  23. National Health and Medical Research Council, Australian Government Department of Health and Ageing & New Zealand Ministry of Health. Nutrient reference values for Australia and New Zealand including recommended dietary intakes. nhmrc.gov.au https://www.nhmrc.gov.au/about-us/publications/nutrient-reference-values-australia-and-new-zealand-including-recommended-dietary-intakes (2006).

  24. Norden. Nordic Nutrition Recommendations 2012: Integrating Nutrition and Physical Activity. 5th Edn Vol. 2014:002 (Nordic Council of Ministers, 2014).

  25. Afssa (Agence française de sécurité sanitaire des aliments). Apports Nutritionnels Conseillés pour la Population Française (Editions Tec&Doc, 2001).

  26. D-A-CH (Deutsche Gesellschaft für Ernährung, Ö. G. f. E., Schweizerische Gesellschaft für Ernährungsforschung, Schweizerische Vereinigung für Ernährung). Referenzwerte für die Nährstoffzufuhr (Reference Value for Nutrient Intake). (Neuer Umschau Buchverlag, 2013).

  27. Department of Health. Report on Health and Social Subjects: 41. Dietary Reference Values for Food, Energy and Nutrients for the United Kingdom (The Stationery Office, 1991).

  28. European Food Safety Authority Scientific opinion on dietary reference values for iodine. EFSA J. 12, 3660 (2014).

    Google Scholar 

  29. Velasco, I., Bath, S. C. & Rayman, M. P. Iodine as essential nutrient during the first 1000 days of life. Nutrients 10, E290 (2018).

    Article  Google Scholar 

  30. Bath, S. C. et al. A systematic review of iodine intake in children, adults, and pregnant women in Europe-comparison against dietary recommendations and evaluation of dietary iodine sources. Nutr. Rev. 80, 2154–2177 (2022).

    Article  PubMed  PubMed Central  Google Scholar 

  31. Chen, W. et al. Iodine intakes of <150 μg/day or >550 μg/day are not recommended during pregnancy: a balance study. J. Nutr. 153, 2041–2050 (2023).

    Article  CAS  PubMed  Google Scholar 

  32. Barr, S. I. Applications of dietary reference intakes in dietary assessment and planning. Appl. Physiol. Nutr. Metab. 31, 66–73 (2006).

    Article  CAS  PubMed  Google Scholar 

  33. Zimmermann, M. B. & Boelaert, K. Iodine deficiency and thyroid disorders. Lancet Diabetes Endocrinol. 3, 286–295 (2015).

    Article  CAS  PubMed  Google Scholar 

  34. Chaker, L., Bianco, A. C., Jonklaas, J. & Peeters, R. P. Hypothyroidism. Lancet 390, 1550–1562 (2017).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  35. Abrams, G. M. & Larsen, P. R. Triiodothyronine and thyroxine in the serum and thyroid glands of iodine-deficient rats. J. Clin. Invest. 52, 2522–2531 (1973).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  36. Greer, M. A., Grimm, Y. & Studer, H. Qualitative changes in the secretion of thyroid hormones induced by iodine deficiency. Endocrinology 83, 1193–1198 (1968).

    Article  CAS  PubMed  Google Scholar 

  37. Delange, F., Camus, M. & Ermans, A. M. Circulating thyroid hormones in endemic goiter. J. Clin. Endocrinol. Metab. 34, 891–895 (1972).

    Article  CAS  PubMed  Google Scholar 

  38. Morreale de Escobar, G., Obregon, M. J. & Escobar del Rey, F. Role of thyroid hormone during early brain development. Eur. J. Endocrinol. 151, U25–U37 (2004).

    Article  CAS  PubMed  Google Scholar 

  39. Glinoer, D. The regulation of thyroid function in pregnancy: pathways of endocrine adaptation from physiology to pathology. Endocr. Rev. 18, 404–433 (1997).

    Article  CAS  PubMed  Google Scholar 

  40. Dumont, J. E., Ermans, A. M., Maenhaut, C., Coppée, F. & Stanbury, J. B. Large goitre as a maladaptation to iodine deficiency. Clin. Endocrinol. 43, 1–10 (1995).

    Article  CAS  Google Scholar 

  41. Ma, Z. F. & Skeaff, S. A. Thyroglobulin as a biomarker of iodine deficiency: a review. Thyroid 24, 1195–1209 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  42. Bath, S. C., Pop, V. J., Furmidge-Owen, V. L., Broeren, M. A. & Rayman, M. P. Thyroglobulin as a functional biomarker of iodine status in a cohort study of pregnant women in the United Kingdom. Thyroid 27, 426–433 (2017).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  43. Taylor, P. N. et al. Global epidemiology of hyperthyroidism and hypothyroidism. Nat. Rev. Endocrinol. 14, 301–316 (2018).

    Article  PubMed  Google Scholar 

  44. Petersen, M. et al. Thyrotoxicosis after iodine fortification. A 21-year Danish population-based study. Clin. Endocrinol. 89, 360–366 (2018).

    Article  CAS  Google Scholar 

  45. Zimmermann, M. B. Salt iodization halves risk of thyrotoxicosis in Denmark. Nat. Rev. Endocrinol. 15, 632–633 (2019).

    Article  PubMed  Google Scholar 

  46. Petersen, M. et al. Changes in subtypes of overt thyrotoxicosis and hypothyroidism following iodine fortification. Clin. Endocrinol. 91, 652–659 (2019).

    Article  CAS  Google Scholar 

  47. Leung, A. M. & Braverman, L. E. Consequences of excess iodine. Nat. Rev. Endocrinol. 10, 136–142 (2014).

    Article  CAS  PubMed  Google Scholar 

  48. Farebrother, J., Zimmermann, M. B. & Andersson, M. Excess iodine intake: sources, assessment, and effects on thyroid function. Ann. N. Y. Acad. Sci. 1446, 44–65 (2019).

    Article  CAS  PubMed  Google Scholar 

  49. Lee, S. Y. & Pearce, E. N. Reproductive endocrinology: iodine intake in pregnancy — even a little excess is too much. Nat. Rev. Endocrinol. 11, 260–261 (2015).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  50. Wu, W. et al. Adverse effects on the thyroid of Chinese pregnant women exposed to long-term iodine excess: optimal and safe tolerable upper intake levels of iodine. Nutrients 15, 1635 (2023).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  51. Shi, X. et al. Optimal and safe upper limits of iodine intake for early pregnancy in iodine-sufficient regions: a cross-sectional study of 7,190 pregnant women in China. J. Clin. Endocrinol. Metab. 100, 1630–1638 (2015).

    Article  CAS  PubMed  Google Scholar 

  52. Abel, M. H. et al. Iodine intake is associated with thyroid function in mild- to moderately iodine deficient pregnant women. Thyroid 28, 1359–1371 (2018).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  53. Williams, G. R. Neurodevelopmental and neurophysiological actions of thyroid hormone. J. Neuroendocrinol. 20, 784–794 (2008).

    Article  CAS  PubMed  Google Scholar 

  54. de Escobar, G. M., Obregon, M. J. & del Rey, F. E. Maternal thyroid hormones early in pregnancy and fetal brain development. Best Pract. Res. Clin. Endocrinol. Metab. 18, 225–248 (2004).

    Article  PubMed  Google Scholar 

  55. Morreale de Escobar, G., Obregon, M. J. & Escobar del Rey, F. Is neuropsychological development related to maternal hypothyroidism or to maternal hypothyroxinemia? J. Clin. Endocrinol. Metab. 85, 3975–3987 (2000).

    CAS  PubMed  Google Scholar 

  56. Berbel, P. & Berbel, J. Hypothyroxinaemia: a subclinical condition affecting neurodevelopment. Expert Rev. Endocrinol. Metab. 5, 563–575 (2010).

    Article  PubMed  Google Scholar 

  57. Lavado-Autric, R. et al. Early maternal hypothyroxinemia alters histogenesis and cerebral cortex cytoarchitecture of the progeny. J. Clin. Invest. 111, 1073–1082 (2003).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  58. Auso, E. et al. A moderate and transient deficiency of maternal thyroid function at the beginning of fetal neocorticogenesis alters neuronal migration. Endocrinology 145, 4037–4047 (2004).

    Article  CAS  PubMed  Google Scholar 

  59. Jansen, T. A. et al. Maternal thyroid function during pregnancy and child brain morphology: a time window-specific analysis of a prospective cohort. Lancet Diabetes Endocrinol. 7, 629–637 (2019).

    Article  CAS  PubMed  Google Scholar 

  60. Mulder, T. A. et al. Urinary iodine concentrations in pregnant women and offspring brain morphology. Thyroid 31, 964–972 (2021).

    Article  CAS  PubMed  Google Scholar 

  61. Gordon, R. C. et al. Iodine supplementation improves cognition in mildly iodine-deficient children. Am. J. Clin. Nutr. 90, 1264–1271 (2009).

    Article  CAS  PubMed  Google Scholar 

  62. Zimmermann, M. B. et al. Iodine supplementation improves cognition in iodine-deficient schoolchildren in Albania: a randomized, controlled, double-blind study. Am. J. Clin. Nutr. 83, 108–114 (2006).

    Article  CAS  PubMed  Google Scholar 

  63. Hynes, K. L., Otahal, P., Burgess, J. R., Oddy, W. H. & Hay, I. Reduced educational outcomes persist into adolescence following mild iodine deficiency in utero, despite adequacy in childhood: 15-year follow-up of the gestational iodine cohort investigating auditory processing speed and working memory. Nutrients 9, 1354 (2017).

    Article  PubMed  PubMed Central  Google Scholar 

  64. de Escobar, G. M. Sporadic cretinism: a dangerous misnomer. Eur. Thyroid J. 2, 68 (2013).

    Article  PubMed  PubMed Central  Google Scholar 

  65. Chen, Z. P. & Hetzel, B. S. Cretinism revisited. Best Pract. Res. Clin. Endocrinol. Metab. 24, 39–50 (2010).

    Article  PubMed  Google Scholar 

  66. Bath, S. C. The effect of iodine deficiency during pregnancy on child development. Proc. Nutr. Soc. 78, 150–160 (2019).

    Article  PubMed  Google Scholar 

  67. Dineva, M., Fishpool, H., Rayman, M. P., Mendis, J. & Bath, S. C. Systematic review and meta-analysis of the effects of iodine supplementation on thyroid function and child neurodevelopment in mildly-to-moderately iodine-deficient pregnant women. Am. J. Clin. Nutr. 112, 389–412 (2020).

    Article  PubMed  Google Scholar 

  68. Bath, S. C., Steer, C. D., Golding, J., Emmett, P. & Rayman, M. P. Effect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children: results from the Avon Longitudinal Study of Parents and Children (ALSPAC). Lancet 382, 331–337 (2013).

    Article  CAS  PubMed  Google Scholar 

  69. Levie, D. et al. Association of maternal iodine status with child IQ: a meta-analysis of individual-participant data. J. Clin. Endocrinol. Metab. 104, 5957–5967 (2019).

    Article  PubMed  PubMed Central  Google Scholar 

  70. Dineva, M. et al. Similarities and differences of dietary and other determinants of iodine status in pregnant women from three European birth cohorts. Eur. J. Nutr. 59, 371–387 (2019).

    Article  PubMed  Google Scholar 

  71. Levie, D. et al. Maternal iodine status during pregnancy is not consistently associated with attention-deficit hyperactivity disorder or autistic traits in children. J. Nutr. 150, 1516–1528 (2020).

    Article  PubMed  PubMed Central  Google Scholar 

  72. Zhou, S. J. et al. The effect of iodine supplementation in pregnancy on early childhood neurodevelopment and clinical outcomes: results of an aborted randomised placebo-controlled trial. Trials 16, 563 (2015).

    Article  PubMed  PubMed Central  Google Scholar 

  73. Pharoah, P. O., Buttfield, I. H. & Hetzel, B. S. Neurological damage to the fetus resulting from severe iodine deficiency during pregnancy. Lancet 1, 308–310 (1971).

    Article  CAS  PubMed  Google Scholar 

  74. Pharoah, P. O., Buttfield, I. H. & Hetzel, B. S. The effect of iodine prophylaxis on the incidence of endemic cretinism. Adv. Exp. Med. Biol. 30, 201–221 (1972).

    CAS  PubMed  Google Scholar 

  75. Pharoah, P. O. & Connolly, K. J. A controlled trial of iodinated oil for the prevention of endemic cretinism: a long-term follow-up. Int. J. Epidemiol. 16, 68–73 (1987).

    Article  CAS  PubMed  Google Scholar 

  76. Gowachirapant, S. et al. Effect of iodine supplementation in pregnant women on child neurodevelopment: a randomised, double-blind, placebo-controlled trial. Lancet Diabetes Endocrinol. 5, 853–863 (2017).

    Article  CAS  PubMed  Google Scholar 

  77. Verhagen, N. J. E. et al. Iodine supplementation in mildly iodine-deficient pregnant women does not improve maternal thyroid function or child development: a secondary analysis of a randomized controlled trial. Front. Endocrinol. 11, 572984 (2020).

    Article  Google Scholar 

  78. Manousou, S. et al. Role of iodine-containing multivitamins during pregnancy for children’s brain function: protocol of an ongoing randomised controlled trial: the SWIDDICH study. BMJ Open 8, e019945 (2018).

    Article  PubMed  PubMed Central  Google Scholar 

  79. Best, K. P. et al. Prenatal iodine supplementation and early childhood neurodevelopment: the PoppiE trial – study protocol for a multicentre randomised controlled trial. BMJ Open 13, e071359 (2023).

    Article  PubMed  PubMed Central  Google Scholar 

  80. Manousou, S., Eggertsen, R., Hulthén, L. & Filipsson Nyström, H. A randomized, double-blind study of iodine supplementation during pregnancy in Sweden: pilot evaluation of maternal iodine status and thyroid function. Eur. J. Nutr. 60, 3411–3422 (2021).

    CAS  PubMed  PubMed Central  Google Scholar 

  81. Moleti, M. et al. Maternal thyroid function in different conditions of iodine nutrition in pregnant women exposed to mild-moderate iodine deficiency: an observational study. Clin. Endocrinol. 74, 762–768 (2011).

    Article  CAS  Google Scholar 

  82. Rebagliato, M. et al. Iodine intake and maternal thyroid function during pregnancy. Epidemiology 21, 62–69 (2010).

    Article  PubMed  Google Scholar 

  83. Abel, M. H. et al. Suboptimal maternal iodine intake is associated with impaired child neurodevelopment at 3 years of age in the norwegian mother and child cohort study. J. Nutr. 147, 1314–1324 (2017).

    Article  CAS  PubMed  Google Scholar 

  84. Abel, M. H. et al. Maternal iodine intake and offspring attention-deficit/hyperactivity disorder: results from a large prospective cohort study. Nutrients 9, 1239 (2017).

    Article  PubMed  PubMed Central  Google Scholar 

  85. WHO. New WHA resolution to accelerate efforts on food micronutrient fortification. who.int https://www.who.int/news/item/29-05-2023-new-wha-resolution-to-accelerate-efforts-on-food-micronutrient-fortification (2023).

  86. UNICEF. First Call for Children. World declaration and plan of action from the World Summit for Children. unicef.org https://www.unicef.org/documents/world-summit-children (1990).

  87. WHO. Overcoming iodine deficiency disorders. Resolution WHA 43.2. In: Proceedings of the Forty-third World Health Assembly, Geneva, 7–17 May 1990 (World Health Organization, 1990).

  88. United Nations Department of Economic and Social Affairs. UN Sustainable Development Goals. United Nations https://sdgs.un.org/goals (2015).

  89. Dold, S. et al. Universal salt iodization provides sufficient dietary iodine to achieve adequate iodine nutrition during the first 1000 days: a cross-sectional multicenter study. J. Nutr. 148, 587–598 (2018).

    Article  PubMed  Google Scholar 

  90. Global Fortification Data Exchange. Map: fortification legislation. FortificationData.org https://fortificationdata.org/interactive-map-fortification-legislation/ (2023).

  91. UNICEF. Iodine. Unicef.org https://data.unicef.org/topic/nutrition/iodine/ (2023).

  92. World Health Organization. Salt as a vehicle for fortification. Report of a WHO expert consultation. who.int http://www.who.int/nutrition/publications/micronutrients/9789241596787/en/index.html (2008).

  93. Dasgupta, P. K., Liu, Y. & Dyke, J. V. Iodine nutrition: iodine content of iodized salt in the United States. Env. Sci. Technol. 42, 1315–1323 (2008).

    Article  CAS  Google Scholar 

  94. Fischer, L., Andersson, M., Braegger, C. & Herter-Aeberli, I. Iodine intake in the Swiss population 100 years after the introduction of iodised salt: a cross-sectional national study in children and pregnant women. Eur. J. Nutr. 63, 573–587 (2024).

    Article  CAS  PubMed  Google Scholar 

  95. Knowles, J., Codling, K., Houston, R. & Gorstein, J. Introduction to the programme guidance for the use of iodised salt in processed foods and its pilot implementation, strengthening strategies to improve iodine status. PLoS ONE 18, e0274301 (2023).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  96. Völzke, H. et al. How do we improve the impact of iodine deficiency disorders prevention in Europe and beyond? Eur. Thyroid J. 7, 193–200 (2018).

    Article  PubMed  PubMed Central  Google Scholar 

  97. EUthyroid consortium The krakow declaration on iodine: tasks and responsibilities for prevention programs targeting iodine deficiency disorders. Eur. Thyroid J. 7, 201–204 (2018).

    Article  Google Scholar 

  98. Volzke, H. et al. Ensuring effective prevention of iodine deficiency disorders. Thyroid 26, 189–196 (2016).

    Article  PubMed  Google Scholar 

  99. Kayes, L., Mullan, K. R. & Woodside, J. V. A review of current knowledge about the importance of iodine among women of child-bearing age and healthcare professionals. J. Nutr. Sci. 11, e56 (2022).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  100. World Health Organization & UNICEF. Reaching Optimal Iodine Nutrition in Pregnant and Lactating Women and Young Children. Joint Statement of the World Health Organization and the United Nations Children’s Fund (World Health Organisation, Geneva, Switzerland, 2007).

  101. National Health and Medical Research Council. Iodine supplementation for pregnant and breastfeeding women. nhmrc.gov.au https://www.nhmrc.gov.au/about-us/publications/iodine-supplementation-pregnant-and-breastfeeding-women (2010).

  102. Alexander, E. K. et al. 2017 guidelines of the American Thyroid Association for the diagnosis and management of thyroid disease during pregnancy and the postpartum. Thyroid 27, 315–389 (2017).

    Article  PubMed  Google Scholar 

  103. Lazarus, J. et al. 2014 European thyroid association guidelines for the management of subclinical hypothyroidism in pregnancy and in children. Eur. Thyroid J. 3, 76–94 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  104. Martin, J. C., Savige, G. S. & Mitchell, E. K. Health knowledge and iodine intake in pregnancy. Aust. N. Z. J. Obstet. Gynaecol. 54, 312–316 (2014).

    Article  PubMed  Google Scholar 

  105. Cooray, S. D. et al. Awareness and use of iodine supplementation among Australian women attending a low-risk pregnancy clinic. Aust. N. Z. J. Obstet. Gynaecol. 58, E16–E17 (2018).

    Article  PubMed  Google Scholar 

  106. Hine, T., Zhao, Y., Begley, A., Skeaff, S. & Sherriff, J. Iodine-containing supplement use by pregnant women attending antenatal clinics in Western Australia. Aust. N. Z. J. Obstet. Gynaecol. 58, 636–642 (2018).

    Article  PubMed  Google Scholar 

  107. Reynolds, A. N. & Skeaff, S. A. Maternal adherence with recommendations for folic acid and iodine supplements: a cross-sectional survey. Aust. N. Z. J. Obstet. Gynaecol. 58, 125–127 (2018).

    Article  PubMed  Google Scholar 

  108. Guess, K., Malek, L., Anderson, A., Makrides, M. & Zhou, S. J. Knowledge and practices regarding iodine supplementation: a national survey of healthcare providers. Women Birth 30, e56–e60 (2017).

    Article  PubMed  Google Scholar 

  109. De Leo, S., Pearce, E. N. & Braverman, L. E. Iodine supplementation in women during preconception, pregnancy, and lactation: current clinical practice by U.S. obstetricians and midwives. Thyroid 27, 434–439 (2017).

    Article  PubMed  Google Scholar 

  110. Combet, E., Bouga, M., Pan, B., Lean, M. E. & Christopher, C. O. Iodine and pregnancy - a UK cross-sectional survey of dietary intake, knowledge and awareness. Br. J. Nutr. 114, 108–117 (2015).

    Article  CAS  PubMed  Google Scholar 

  111. Scientific Advisory Committee on Nutrition. Scientific Advisory Committee on Nutrition: Salt and Health (The Stationery Office, 2003).

  112. He, F. J. et al. Effect of salt reduction on iodine status assessed by 24 hour urinary iodine excretion in children and their families in northern China: a substudy of a cluster randomised controlled trial. BMJ Open 6, e011168 (2016).

    Article  PubMed  PubMed Central  Google Scholar 

  113. Verkaik-Kloosterman, J., van t Veer, P. & Ocké, M. C. Reduction of salt: will iodine intake remain adequate in The Netherlands? Br. J. Nutr. 104, 1712–1718 (2010).

    Article  CAS  PubMed  Google Scholar 

  114. WHO. Universal salt iodization and sodium intake reduction. Compatible, cost-effective strategies of great public health benefit. who.int https://www.who.int/publications/i/item/9789240053717 (2022).

  115. Hawkes, C., Ruel, M. T., Salm, L., Sinclair, B. & Branca, F. Double-duty actions: seizing programme and policy opportunities to address malnutrition in all its forms. Lancet 395, 142–155 (2020).

    Article  PubMed  Google Scholar 

  116. Popkin, B. M., Corvalan, C. & Grummer-Strawn, L. M. Dynamics of the double burden of malnutrition and the changing nutrition reality. Lancet 395, 65–74 (2020).

    Article  PubMed  Google Scholar 

  117. Wells, J. C. et al. The double burden of malnutrition: aetiological pathways and consequences for health. Lancet 395, 75–88 (2020).

    Article  PubMed  Google Scholar 

  118. Fahim, O. et al. Double burden of malnutrition in Afghanistan: secondary analysis of a national survey. PLoS ONE 18, e0284952 (2023).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  119. Farebrother, J. et al. Iodine status of pregnant women with obesity from inner city populations in the United Kingdom. Eur. J. Clin. Nutr. 75, 801–808 (2020).

    Article  PubMed  Google Scholar 

  120. Redfern, K. M., Hollands, H. J., Welch, C. R., Pinkney, J. H. & Rees, G. A. Dietary Intakes of folate, vitamin D and iodine during the first trimester of pregnancy and the association between supplement use and demographic characteristics amongst white caucasian women living with obesity in the UK. Nutrients 14, 5135 (2022).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  121. De Angelis, S. et al. Obesity and monitoring iodine nutritional status in schoolchildren: is body mass index a factor to consider? Thyroid 31, 829–840 (2021).

    Article  PubMed  Google Scholar 

  122. Manousou, S. et al. A paleolithic-type diet results in iodine deficiency: a 2-year randomized trial in postmenopausal obese women. Eur. J. Clin. Nutr. 72, 124–129 (2018).

    Article  CAS  PubMed  Google Scholar 

  123. O’Kane, M. et al. British Obesity and Metabolic Surgery Society Guidelines on perioperative and postoperative biochemical monitoring and micronutrient replacement for patients undergoing bariatric surgery — 2020 update. Obes. Rev. 21, e13087 (2020).

    Article  PubMed  PubMed Central  Google Scholar 

  124. Chiung-Hui Peng, C. et al. Changes in urinary iodine levels following bariatric surgery. Endocr. Pract. 29, 710–715 (2023).

    Article  PubMed  Google Scholar 

  125. Michalaki, M. et al. Dietary iodine absorption is not influenced by malabsorptive bariatric surgery. Obes. Surg. 24, 1921–1925 (2014).

    Article  CAS  PubMed  Google Scholar 

  126. Manousou, S. et al. Iodine status after bariatric surgery-a prospective 10-year report from the swedish obese subjects (SOS) study. Obes. Surg. 28, 349–357 (2018).

    Article  PubMed  Google Scholar 

  127. Lecube, A. et al. Iodine deficiency is higher in morbid obesity in comparison with late after bariatric surgery and non-obese women. Obes. Surg. 25, 85–89 (2015).

    Article  PubMed  Google Scholar 

  128. Martini, D. et al. Principles of sustainable healthy diets in worldwide dietary guidelines: efforts so far and future perspectives. Nutrients 13, 1827 (2021).

    Article  PubMed  PubMed Central  Google Scholar 

  129. Eveleigh, E. R., Coneyworth, L. & Welham, S. J. M. Systematic review and meta-analysis of iodine nutrition in modern vegan and vegetarian diets. Br. J. Nutr. 130, 1580–1594 (2023).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  130. Alae-Carew, C. et al. The role of plant-based alternative foods in sustainable and healthy food systems: consumption trends in the UK. Sci. Total. Environ. 807, 151041 (2022).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  131. van der Reijden, O. L., Zimmermann, M. B. & Galetti, V. Iodine in dairy milk: sources, concentrations and importance to human health. Best. Pract. Res. Clin. Endocrinol. Metab. 31, 385–395 (2017).

    Article  PubMed  Google Scholar 

  132. Dahl, L., Aarsland, T. E., Naess, S., Aakre, I. & Markhus, M. W. Iodine concentration in plant-based milk products available on the Norwegian market. Norwegian J. Nutr., https://doi.org/10.18261/ntfe.19.2.2 (2021).

    Article  PubMed  Google Scholar 

  133. Ma, W. S., He, X. & Braverman, L. E. Iodine content in milk alternatives. Thyroid 26, 1308–1310 (2016).

    Article  CAS  PubMed  Google Scholar 

  134. Vance, K., Makhmudov, A., Jones, R. L. & Caldwell, K. L. Re: “Iodine Content in Milk Alternatives” by Ma et al. (Thyroid 2016;26:1308-1310). Thyroid 27, 748–749 (2017).

    Article  PubMed  Google Scholar 

  135. Bath, S. C. et al. Iodine concentration of milk-alternative drinks available in the UK in comparison with cows’ milk. Br. J. Nutr. 118, 525–532 (2017).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  136. Dineva, M., Rayman, M. P. & Bath, S. C. Iodine status of consumers of milk-alternative drinks versus cows’ milk: data from the UK National Diet and Nutrition Survey. Br. J. Nutr. 126, 28–36 (2021).

    Article  CAS  PubMed  Google Scholar 

  137. Beal, T., Ortenzi, F. & Fanzo, J. Estimated micronutrient shortfalls of the EAT-Lancet planetary health diet. Lancet Planet. Health 7, e233–e237 (2023).

    Article  PubMed  Google Scholar 

  138. Nicol, K., Nugent, A. P., Woodside, J. V., Hart, K. H. & Sarah, C. B. Iodine and plant-based diets – a narrative review and calculation of iodine content. Br. J. Nutr. 131, 265–275 (2023).

    Article  PubMed  PubMed Central  Google Scholar 

  139. Dawczynski, C. et al. Nutrient intake and nutrition status in vegetarians and vegans in comparison to omnivores - the nutritional evaluation (NuEva) study. Front. Nutr. 9, 819106 (2022).

    Article  PubMed  PubMed Central  Google Scholar 

  140. Peddie, M. C. et al. Micronutrient status of New Zealand adolescent women consuming vegetarian and non-vegetarian diets. Asia Pac. J. Clin. Nutr. 32, 434–443 (2023).

    PubMed  Google Scholar 

  141. Neufingerl, N. & Eilander, A. Nutrient intake and status in adults consuming plant-based diets compared to meat-eaters: a systematic review. Nutrients 14, 29 (2021).

    Article  PubMed  PubMed Central  Google Scholar 

  142. Zimmermann, M. B. & Hurrell, R. F. Nutritional iron deficiency. Lancet 370, 511–520 (2007).

    Article  CAS  PubMed  Google Scholar 

  143. Rayman, M. P. Selenium and human health. Lancet 379, 1256–1268 (2012).

    Article  CAS  PubMed  Google Scholar 

  144. Di Dalmazi, G. & Giuliani, C. Plant constituents and thyroid: a revision of the main phytochemicals that interfere with thyroid function. Food Chem. Toxicol. 152, 112158 (2021).

    Article  PubMed  Google Scholar 

  145. Felker, P., Bunch, R. & Leung, A. M. Concentrations of thiocyanate and goitrin in human plasma, their precursor concentrations in brassica vegetables, and associated potential risk for hypothyroidism. Nutr. Rev. 74, 248–258 (2016).

    Article  PubMed  PubMed Central  Google Scholar 

  146. Doerge, D. R. & Sheehan, D. M. Goitrogenic and estrogenic activity of soy isoflavones. Env. Health Perspect. 110, 349–353 (2002).

    Article  CAS  Google Scholar 

  147. Van Wyk, J. J., Arnold, M. B., Wynn, J. & Pepper, F. The effects of a soybean product on thyroid function in humans. Pediatrics 24, 752–760 (1959).

    Article  PubMed  Google Scholar 

  148. Shepard, T. H., Pyne, G. E., Kirschvink, J. F. & McLean, C. M. Soybean goiter - report of three cases. N. Engl. J. Med. 262, 1099–1103 (1960).

    Article  Google Scholar 

  149. Leung, A. M., Pearce, E. N. & Braverman, L. E. Iodine content of prenatal multivitamins in the United States. N. Engl. J. Med. 360, 939–940 (2009).

    Article  CAS  PubMed  Google Scholar 

  150. Aakre, I. et al. Commercially available kelp and seaweed products — valuable iodine source or risk of excess intake? Food Nutr. Res., https://doi.org/10.29219/fnr.v65.7584 (2021).

    Article  PubMed  PubMed Central  Google Scholar 

  151. Zimmermann, M. & Delange, F. Iodine supplementation of pregnant women in Europe: a review and recommendations. Eur. J. Clin. Nutr. 58, 979–984 (2004).

    Article  CAS  PubMed  Google Scholar 

  152. Crawford, B. A. et al. Iodine toxicity from soy milk and seaweed ingestion is associated with serious thyroid dysfunction. Med. J. Aust. 193, 413–415 (2010).

    Article  PubMed  Google Scholar 

  153. Di Matola, T., Zeppa, P., Gasperi, M. & Vitale, M. Thyroid dysfunction following a kelp-containing marketed diet. BMJ Case Rep. 2014, bcr2014206330 (2014).

    Article  PubMed  PubMed Central  Google Scholar 

  154. Kiferle, C., Gonzali, S., Holwerda, H. T., Ibaceta, R. R. & Perata, P. Tomato fruits: a good target for iodine biofortification. Front. Plant Sci. 4, 205 (2013).

    Article  PubMed  PubMed Central  Google Scholar 

  155. Tonacchera, M. et al. Iodine fortification of vegetables improves human iodine nutrition: in vivo evidence for a new model of iodine prophylaxis. J. Clin. Endocrinol. Metab. 98, E694–E697 (2013).

    Article  CAS  PubMed  Google Scholar 

  156. Welk, A. K., Kleine-Kalmer, R., Daum, D. & Enneking, U. Consumer acceptance and market potential of iodine-biofortified fruit and vegetables in Germany. Nutrients 13, 4198 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  157. Health Council of the Netherlands. Dietary reference values for vitamins and minerals for adults [in Dutch: voedingsnormen voor vitamines en mineralen voor volwassenen]. Gezondheit.nl https://www.gezondheidsraad.nl/documenten/adviezen/2018/09/18/gezondheidsraad-herziet-voedingsnormen-voor-volwassenen (2018).

  158. GOV.UK Public Health England. The Composition of foods integrated dataset (CoFID). gov.uk https://www.gov.uk/government/publications/composition-of-foods-integrated-dataset-cofid (2021).

  159. Food Standards Agency. Food Portion Sizes (The Stationery Office, 2002).

Download references

Author information

Authors and Affiliations

  1. Department of Nutrition, Food and Exercise Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK

    Sarah C. Bath

Authors
  1. Sarah C. Bath
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Sarah C. Bath.

Ethics declarations

Competing interests

S.C.B. has received an honorarium from Oatly UK and Dairy UK for delivering webinars and online videos for health-care professionals.

Peer review

Peer review information

Nature Reviews Endocrinology thanks Karin Amrein, who co-reviewed with Heike Rampler; and Elizabeth Pearce for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Related links

The Iodine Global Network: https://ign.org/

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Bath, S.C. Thyroid function and iodine intake: global recommendations and relevant dietary trends. Nat Rev Endocrinol (2024). https://doi.org/10.1038/s41574-024-00983-z

Download citation

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1038/s41574-024-00983-z

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing