Iodine
•Last Updated: September 28 2022
Iodine is a mineral for thyroid function found mostly in iodized table salt, fish, and highest in seaweed. Despite most first world diets being sufficient in iodine, it may benefit those who do not consume seafood and are also in a high risk population (pregnancy and intentional salt restriction).
Iodine is most often used for
Last Updated: September 28 2022
Iodine is an essential mineral in the diet due to its importance towards cognition and fetal development secondary to being required for thyroid hormones; iodine is central to the active thyroid hormones T3 and T4, and a true iodine deficiency results in less of these hormones and may result in reduced cognition (if a subclinical deficiency) or cretinism (severe deficiency in utero).
Despite the importance of iodine, it is not a common dietary supplement. This is due to table salt being iodized (added iodine) and even relative deficiencies being quite rare in first world countries (it is a common issue in developing countries due to iodine only naturally occurring from fish and seaweed which may not be consumed); actually benefitting from supplementation of iodine requires a 'perfect storm' of situations to occur which are outlined in the dosing section but not many people will meet these requirements.
Supplementation of high doses of iodine in otherwise healthy people does not appear to result in much, since it is readily excreted and normalized. There may be a very small and (clinically) irrelevant antiinflammatory effect and a small reduction in thyroid hormones (rather than an increase), but that seems to be it. Obscenely high doses for a prolonged period of time, which occurs with consumption of unprocessed seaweed (mostly kombu) will result in benign goiter in all persons and thyrotoxicity in some persons with underlying thyroid issues.
Iodine should not be confused with:
- Table salt (chemically sodium chloride
- but it also contains iodine)
Supplementation of iodine is designed to circumvent a deficiency, and deficiencies of iodine are quite rare in first world countries. For those in a first world country, iodine should only be considered if you meet all of the following requirements:
- You are a vegetarian or vegan who actively avoids processed foods, or a meat eater who never eats fish and avoids processed foods
- You avoid adding additional iodized salt to your diet
- You avoid consumption of seaweed or seaweed based products (such as sushi, which are wrapped with Nori)
Assuming all the criteria are met, recommendations for iodine intake tend to be in the range of 75-150 μg (micrograms) or 0.075-0.15 mg daily while higher doses are not inherently dangerous although there may be a slight suppression of thyroid hormones (T3 and T4) at 500 μg or above.
What works and what doesn't?
Unlock the full potential of Examine
Latest ResearchRead all studies
2.^Teas J, Baldeón ME, Chiriboga DE, Davis JR, Sarriés AJ, Braverman LECould dietary seaweed reverse the metabolic syndromeAsia Pac J Clin Nutr.(2009)
3.^Iodine uptake in Laminariales involves extracellular, haloperoxidase-mediated oxidation of iodide.()
4.^Lee SM, Lewis J, Buss DH, Holcombe GD, Lawrance PRIodine in British foods and dietsBr J Nutr.(1994 Sep)
5.^Nagataki SThe average of dietary iodine intake due to the ingestion of seaweeds is 1.2 mg/day in JapanThyroid.(2008 Jun)
6.^Teas J, Pino S, Critchley A, Braverman LEVariability of iodine content in common commercially available edible seaweedsThyroid.(2004 Oct)
7.^Assessment of Japanese iodine intake based on seaweed consumption in Japan: A literature-based analysis.()
8.^Teas J, Braverman LE, Kurzer MS, Pino S, Hurley TG, Hebert JRSeaweed and soy: companion foods in Asian cuisine and their effects on thyroid function in American womenJ Med Food.(2007 Mar)
10.^Aquaron R, Delange F, Marchal P, Lognoné V, Ninane LBioavailability of seaweed iodine in human beingsCell Mol Biol (Noisy-le-grand).(2002 Jul)
11.^Nishiyama S, Mikeda T, Okada T, Nakamura K, Kotani T, Hishinuma ATransient hypothyroidism or persistent hyperthyrotropinemia in neonates born to mothers with excessive iodine intakeThyroid.(2004 Dec)
12.^GREER MA, ASTWOOD EBThe antithyroid effect of certain foods in man as determined with radioactive iodineEndocrinology.(1948 Aug)
14.^Doerge DR, Chang HCInactivation of thyroid peroxidase by soy isoflavones, in vitro and in vivoJ Chromatogr B Analyt Technol Biomed Life Sci.(2002 Sep 25)
15.^Rose M, Miller P, Baxter M, Appleton G, Crews H, Croasdale MBromine and iodine in 1997 UK total diet study samplesJ Environ Monit.(2001 Aug)
16.^Halogen speciation in the rat thyroid: Simultaneous determination of bromine and iodine by short-term INAA.()
17.^Ishizuki Y, Yamauchi K, Miura YTransient thyrotoxicosis induced by Japanese kombuNihon Naibunpi Gakkai Zasshi.(1989 Feb 20)
18.^Konno N, Makita H, Yuri K, Iizuka N, Kawasaki KAssociation between dietary iodine intake and prevalence of subclinical hypothyroidism in the coastal regions of JapanJ Clin Endocrinol Metab.(1994 Feb)
19.^Suzuki H, Higuchi T, Sawa K, Ohtaki S, Horiuchi Y"Endemic coast goitre" in Hokkaido, JapanActa Endocrinol (Copenh).(1965 Oct)
20.^Tajiri J, Higashi K, Morita M, Umeda T, Sato TStudies of hypothyroidism in patients with high iodine intakeJ Clin Endocrinol Metab.(1986 Aug)
22.^Patil VP, Kulkarni AP, Jacques TIodine induced thyrotoxicosis following povidine-iodine dressings: a case reportCrit Care Resusc.(2003 Sep)
24.^Malasanos T, Chaudhari M, Selman-Almonte A, Pino S, Previti M, Braverman L, Rosenbloom AIodine deficiency, iodine content of salt and knowledge of iodine supplementation in the Dominican RepublicJ Trop Pediatr.(2007 Jun)
25.^Nepal AK, Raj Shakya P, Gelal B, Lamsal M, Brodie DA, Baral NHousehold salt iodine content estimation with the use of rapid test kits and iodometric titration methodsJ Clin Diagn Res.(2013 May)
26.^The effects of oral iodized oil on intelligence, thyroid status, and somatic growth in school-age children from an area of endemic goiter.()
27.^Huda SN, Grantham-McGregor SM, Tomkins ACognitive and motor functions of iodine-deficient but euthyroid children in Bangladesh do not benefit from iodized poppy seed oil (Lipiodol)J Nutr.(2001 Jan)
28.^Trumbo P, Yates AA, Schlicker S, Poos MDietary reference intakes: vitamin A, vitamin K, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zincJ Am Diet Assoc.(2001 Mar)
30.^Public Health Committee of the American Thyroid Association, Becker DV, Braverman LE, Delange F, Dunn JT, Franklyn JA, Hollowell JG, Lamm SH, Mitchell ML, Pearce E, Robbins J, Rovet JFIodine supplementation for pregnancy and lactation-United States and Canada: recommendations of the American Thyroid AssociationThyroid.(2006 Oct)
31.^Recommended iodine levels in salt and guidelines for monitoring their adequacy and effectiveness.()
32.^Mulrine HM, Skeaff SA, Ferguson EL, Gray AR, Valeix PBreast-milk iodine concentration declines over the first 6 mo postpartum in iodine-deficient womenAm J Clin Nutr.(2010 Oct)
33.^Nagataki S, Shizume K, Nakao KThyroid function in chronic excess iodide ingestion: comparison of thyroidal absolute iodine uptake and degradation of thyroxine in euthyroid Japanese subjectsJ Clin Endocrinol Metab.(1967 May)
35.^Joshinaga J, Morita M, Yukawa M, Shiraishi K, Kawamura HCertified reference material for analytical quality assurance of minor and trace elements in food and related matrixes based on a typical Japanese diet: interlaboratory studyJ AOAC Int.(2001 Jul-Aug)
36.^Iso H, Date C, Noda H, Yoshimura T, Tamakoshi A; JACC Study GroupFrequency of food intake and estimated nutrient intake among men and women: the JACC StudyJ Epidemiol.(2005 Mar)
38.^Hetzel BSEliminating iodine deficiency disorders--the role of the International Council in the global partnershipBull World Health Organ.(2002)
39.^Plantin-Carrenard E, Beaudeux J, Foglietti MPhysiopathology of iodine: current interest of its measurement in biological fluidsAnn Biol Clin (Paris).(2000 Jul-Aug)
41.^Santiago-Fernandez P, Torres-Barahona R, Muela-Martínez JA, Rojo-Martínez G, García-Fuentes E, Garriga MJ, León AG, Soriguer FIntelligence quotient and iodine intake: a cross-sectional study in childrenJ Clin Endocrinol Metab.(2004 Aug)
42.^Hetzel BS, Potter BJ, Dulberg EMThe iodine deficiency disorders: nature, pathogenesis and epidemiologyWorld Rev Nutr Diet.(1990)
44.^Pharoah PO, Buttfield IH, Hetzel BSNeurological damage to the fetus resulting from severe iodine deficiency during pregnancyLancet.(1971 Feb 13)
45.^Bürgi H, Supersaxo Z, Selz BIodine deficiency diseases in Switzerland one hundred years after Theodor Kocher's survey: a historical review with some new goitre prevalence dataActa Endocrinol (Copenh).(1990 Dec)
48.^Taga I, Oumbe VA, Johns R, Zaidi MA, Yonkeu NJ, Altosaar IYouth of West Cameroon are at high risk of developing IDD due to low dietary iodine and high dietary thiocyanateAfr Health Sci.(2008 Dec)
49.^Draper A, Lewis J, Malhotra N, Wheeler EThe energy and nutrient intakes of different types of vegetarian: a case for supplementsBr J Nutr.(1993 Jan)
52.^Remer T, Neubert A, Manz FIncreased risk of iodine deficiency with vegetarian nutritionBr J Nutr.(1999 Jan)
53.^Krajcovicová-Kudlácková M, Bucková K, Klimes I, Seboková EIodine deficiency in vegetarians and vegansAnn Nutr Metab.(2003)
54.^Navarro AM, Suen VM, Souza IM, De Oliveira JE, Marchini JSPatients with severe bowel malabsorption do not have changes in iodine statusNutrition.(2005 Sep)
56.^Zhao J, Chen Z, Maberly GIodine-rich drinking water of natural origin in ChinaLancet.(1998 Dec 19-26)
57.^Li M, Liu DR, Qu CY, Zhang PY, Qian QD, Zhang CD, Jia QZ, Wang HX, Eastman CJ, Boyages SC, et alEndemic goitre in central China caused by excessive iodine intakeLancet.(1987 Aug 1)
59.^Zimmermann MB, Ito Y, Hess SY, Fujieda K, Molinari LHigh thyroid volume in children with excess dietary iodine intakesAm J Clin Nutr.(2005 Apr)
60.^Hollowell JG, Staehling NW, Hannon WH, Flanders DW, Gunter EW, Maberly GF, Braverman LE, Pino S, Miller DT, Garbe PL, DeLozier DM, Jackson RJIodine nutrition in the United States. Trends and public health implications: iodine excretion data from National Health and Nutrition Examination Surveys I and III (1971-1974 and 1988-1994J Clin Endocrinol Metab.(1998 Oct)
61.^Soriguer F, Gutiérrez-Repiso C, Rubio-Martin E, Linares F, Cardona I, López-Ojeda J, Pacheco M, González-Romero S, Garriga MJ, Velasco I, Santiago P, García-Fuentes EIodine intakes of 100-300 μg/d do not modify thyroid function and have modest anti-inflammatory effectsBr J Nutr.(2011 Jan 25:1-8)
62.^Paul T, Meyers B, Witorsch RJ, Pino S, Chipkin S, Ingbar SH, Braverman LEThe effect of small increases in dietary iodine on thyroid function in euthyroid subjectsMetabolism.(1988 Feb)
63.^Gardner DF, Centor RM, Utiger RDEffects of low dose oral iodide supplementation on thyroid function in normal menClin Endocrinol (Oxf).(1988 Mar)
64.^Chow CC, Phillips DI, Lazarus JH, Parkes ABEffect of low dose iodide supplementation on thyroid function in potentially susceptible subjects: are dietary iodide levels in Britain acceptableClin Endocrinol (Oxf).(1991 May)
65.^Saberi M, Utiger RDAugmentation of thyrotropin responses to thyrotropin-releasing hormone following small decreases in serum thyroid hormone concentrationsJ Clin Endocrinol Metab.(1975 Mar)
66.^Jubiz W, Carlile S, Lagerquist LDSerum thyrotropin and thyroid hormone levels in humans receiving chronic potassium iodideJ Clin Endocrinol Metab.(1977 Feb)
68.^Alikaşifoğlu A, Ozön A, Yordam NSerum insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 levels in severe iodine deficiencyTurk J Pediatr.(2002 Jul-Sep)
69.^Wan Nazaimoon WM, Osman A, Wu LL, Khalid BAEffects of iodine deficiency on insulin-like growth factor-I, insulin-like growth factor-binding protein-3 levels and height attainment in malnourished childrenClin Endocrinol (Oxf).(1996 Jul)
70.^van den Briel T, West CE, Hautvast JG, Ategbo EAMild iodine deficiency is associated with elevated hearing thresholds in children in BeninEur J Clin Nutr.(2001 Sep)
71.^Pharoah P, Buttfield IH, Hetzel BSNeurological damage to the fetus resulting from severe iodine deficiency during pregnancyInt J Epidemiol.(2012 Jun)
72.^Pharoah PO, Connolly KJA controlled trial of iodinated oil for the prevention of endemic cretinism: a long-term follow-upInt J Epidemiol.(1987 Mar)
73.^Delange FAdministration of iodized oil during pregnancy: a summary of the published evidenceBull World Health Organ.(1996)
74.^Luton D, Alberti C, Vuillard E, Ducarme G, Oury JF, Guibourdenche JIodine deficiency in northern Paris area: impact on fetal thyroid mensurationPLoS One.(2011 Feb 16)
76.^Tonacchera M, Pinchera A, Dimida A, Ferrarini E, Agretti P, Vitti P, Santini F, Crump K, Gibbs JRelative potencies and additivity of perchlorate, thiocyanate, nitrate, and iodide on the inhibition of radioactive iodide uptake by the human sodium iodide symporterThyroid.(2004 Dec)
78.^Dohán O, De la Vieja A, Paroder V, Riedel C, Artani M, Reed M, Ginter CS, Carrasco NThe sodium/iodide Symporter (NIS): characterization, regulation, and medical significanceEndocr Rev.(2003 Feb)
80.^Demirel F, Ozer T, Gürel A, Acun C, Ozdemir H, Tomaç N, Unalacak MEffect of iodine supplementation on goiter prevalence among the pediatric population in a severely iodine deficient areaJ Pediatr Endocrinol Metab.(2004 Jan)
81.^Erdoğan MF, Demir O, Emral R, Kamel AN, Erdoğan GMore than a decade of iodine prophylaxis is needed to eradicate goiter among school age children in a moderately iodine-deficient regionThyroid.(2009 Mar)
82.^WOLFF J, CHAIKOFF ILPlasma inorganic iodide as a homeostatic regulator of thyroid functionJ Biol Chem.(1948 Jun)
83.^WOLFF J, CHAIKOFF IL, et alThe temporary nature of the inhibitory action of excess iodine on organic iodine synthesis in the normal thyroidEndocrinology.(1949 Nov)
84.^BRAVERMAN LE, INGBAR SHCHANGES IN THYROIDAL FUNCTION DURING ADAPTATION TO LARGE DOSES OF IODIDEJ Clin Invest.(1963 Aug)
85.^GALTON VA, PITT-RIVERS RThe effect of excessive iodine on the thyroid of the ratEndocrinology.(1959 May)
87.^Müssig K, Thamer C, Bares R, Lipp HP, Häring HU, Gallwitz BIodine-induced thyrotoxicosis after ingestion of kelp-containing teaJ Gen Intern Med.(2006 Jun)
88.^Markou K, Georgopoulos N, Kyriazopoulou V, Vagenakis AGIodine-Induced hypothyroidismThyroid.(2001 May)
89.^Rhee SS, Braverman LE, Pino S, He X, Pearce ENHigh iodine content of Korean seaweed soup: a health risk for lactating women and their infantsThyroid.(2011 Aug)
90.^Shetty KR, Duthie EH JrThyrotoxicosis induced by topical iodine applicationArch Intern Med.(1990 Nov)
Primary Use