Iodine

Iodine is an essential trace element. Good food sources of iodine include: iodized salt, milk seafood, and especially seaweed and fish (e.g., cod and tuna).1 The 100% Daily Value for Iodine (based on a 2,000 kcal diet) is 150 µg.The 100% Daily Value for pregnant or lactating women is 290 μg, effective as of July 26, 2018.11

Forms

  • Potassium Iodide: Potassium iodide is a bioavailable source of the essential mineral, iodine, and is prepared by combining hydriodic acid or hydrogen iodide with potassium bicarbonate.
  • Sea Kelp Powder: Sea kelp powder is produced from kelp plants (Ascophyllum nodosum, Macrocystis pyrifera, or related species) grown in the ocean. The kelp is harvested, dried, and ground into a powder. Sea kelp is a natural source of iodine and other trace minerals.

Major Health Benefits

Iodine is a component of thyroid hormones (T3, T4) produced by the thyroid gland.3 Thyroid hormones help regulate the rate of energy-yielding metabolism, growth, reproduction, nerve, muscle function, and the use of oxygen in the body. Furthermore, iodine plays an important role in skin health and normal cognitive function.4,5 Adequate consumption of iodine can help prevent iodine deficiency, which presents as: mental retardation, hypothyroidism goiter, as well as stunted physical and mental growth.6 Adequate amounts of iodine are especially important for pregnant and lactating women for fetal/infant growth and development, and for brain and nerve function.3

Cautions

The Tolerable Upper Intake Level for Iodine in one day is 1,100 µg for adults.7 Excessive intake of iodine may cause burning sensations in the mouth and throat as well as vomiting and diarrhea. However, these symptoms are associated with consumption of many grams of Iodine.8

Note

Certain foods such as: cabbage, broccoli, Brussels sprouts, and cauliflower contain goitrogens that inhibit iodine absorption and can increase risk of iodine deficiency.9 However, cooking or heating these foods can destroy this enzyme.10

References

  1. Higdon, J. Iodine. Linus Pauling Institute, Oregon State University. 2001. (Reviewed by Pearce, EN in 2010) (Food Sources). http://lpi.oregonstate.edu/mic/minerals/iodine Accessed 7/2015.
  2. US Food and Drug Administration. Guidance for Industry: A Food Labeling Guide (14. Appendix F: Calculate the Percent Daily Value for the Appropriate Nutrients). US Department of Health and Human Services. 2013 January. http://www.fda.gov/Food/GuidanceRegulation/GuidanceDocumentsRegulatoryInformation/LabelingNutrition/ucm064928.htm
  3. Bougma K, Aboud FE, Harding KB, Marquis GS. Iodine and mental development of children 5 years old and under: a systematic review and meta-analysis. Nutrients. 2013 Apr 22;5(4):1384-416. PMID: 23609774; PMCID: PMC3705354.
  4. European Food Safety Authority. Scientific Opinion on Iodine Health Benefits. EFSA Journal 2009; 7(9): 1214.
  5. European Food Safety Authority. Scientific Opinion on Iodine Health Benefits. EFSA Journal 2010; 8(10): 1800.
  6. 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. The National Academic Press. 2001. http://www.nap.edu/catalog/10026/dietary-reference-intakes-for-vitamin-a-vitamin-k-arsenic-boron-chromium-copper-iodine-iron-manganese-molybdenum-nickel-silicon-vanadium-and-zinc (pp. 261)
  7. Dietary Reference Intakes (DRIs): Tolerable Upper Intake Levels, Elements. Food and Nutrition Board, Institute of Medicine, The National Academic Press. 2001. (PDF available)
  8. 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. The National Academic Press. 2001. http://www.nap.edu/catalog/10026/dietary-reference-intakes-for-vitamin-a-vitamin-k-arsenic-boron-chromium-copper-iodine-iron-manganese-molybdenum-nickel-silicon-vanadium-and-zinc (pp. 279).
  9. Higdon, J. Iodine. Linus Pauling Institute, Oregon State University. 2001. (Reviewed by Pearce, EN in 2010) (Goitrogens)
  10. Greer, MA. Goitrogenic substances in food. Am J Clin Nutr. 1957 Jul-Aug;5(4):440-4. PMID: 13444208.
  11. US Food and Drug Administration. Food Labeling: Revision of the Nutrition and Supplement Facts Labels. US Department of Health and Human Services. Federal Register / Vol. 81, No. 103, p. 33982 / May 27, 2016. https://www.gpo.gov/fdsys/pkg/FR-2016-05-27/pdf/2016-11867.pdf