ODS Iodine Initiative

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Table of Contents

Overview

Iodine is an essential nutrient and a component of thyroid hormone. The iodine status (i.e., adequacy or deficiency) of populations and individuals varies with geography, iodine content of the food supply, and use of iodized salt and dietary supplements. Although iodine deficiency is rare in the United States and Canada, it can have serious effects. For example, iodine deficiency can cause birth defects in newborns, lower-than-average IQ in infants and children, and decreased ability to work and think clearly in adults.

ODS originally developed its Iodine Initiative in 2011 in response to concerns that some pregnant women in the United States might have inadequate iodine intakes at a time of high physiologic demand. Six NIH-sponsored workshops have provided expert opinion on public health issues and research needs. In addition, the Scientific Report of the 2020 Dietary Guidelines Advisory Committeeexternal link disclaimer has identified a number of iodine-related concerns.

ODS seeks to address these identified research and resource needs by supporting research and methodology development to provide a scientific base for understanding how best to improve iodine status in individuals with low to moderate risk of deficiency.
 

Programs and Resources

  • Iodine Content of Foods and Dietary Supplements: Characterizing the iodine content of the U.S. food supply was a key recommendation emerging from the NIH-sponsored iodine workshops. To address this issue, ODS has worked with the U.S. Department of Agriculture (USDA), and the U.S. Food and Drug Administration (FDA) to develop databases of the iodine content of foods and dietary supplements:
  • Characterization of U.S. Population-Level Iodine Intake: The National Center for Health Statistics (NCHS) at the Centers for Disease Control and Prevention (CDC) monitors the iodine status of the U.S. population through the National Health and Nutrition Examination Survey (NHANES)external link disclaimer. The CDC evaluates iodine status in NHANES by examining the distribution of urinary iodine concentrations of spot urine collections. However, this method is more suitable for evaluating the iodine status of populations rather than individuals. In addition, ODS analyzed NHANES data to determine the percentage of pregnant women who take supplements containing iodine. While 72% of pregnant women used a dietary supplement, only about 18% used a dietary supplement with iodine, underscoring concerns about whether iodine intake is adequate in this population (Gupta et al, 2018). 

    For the 2021-2022 NHANES examination cycle, NCHS (with funding support from ODS) is collecting information on dietary intake from both foods and dietary supplements that can be mapped to the USDA, FDA and ODS-NIH Database for the Iodine Content of Common Foodsexternal link disclaimer to estimate total iodine intake, urinary iodine concentration, exposure to iodine uptake inhibitors, and thyroid status as indicated by clinical laboratory measurements.
     
  • Analytical Methods, Reference Materials, and Standards for Assessing Iodine Status: Analytical quality control programs and standard reference materials for foods and other biological samples play an important role in ensuring high quality data. ODS supports the development of these materials and related protocols through its interactions with the National Institute of Standards and Technology (NIST) and the CDC.

Funding Opportunities for Investigator-Initiated Research

ODS along with its NIH partners encourages the submission of investigator-initiated research applications on topics related to iodine nutrition in humans.

Relevant topics include but are not limited to:

  • Iodine nutrition in humans and appropriate animal models, including intake of iodine from foods, beverages, supplements, and other dietary sources.
  • Laboratory assessment of iodine status, including development and validation of biomarkers of iodine status in individuals and populations.
  • Health effects and safety of iodine supplementation. 
  • Effects of iodine intake and status on maternal health, pregnancy outcomes, and infant and child development, including neurocognitive and neuromuscular development.

Conference Reports

  • 2014 Iodine Workshops: ODS held three workshops in 2014. The results were published in September 2016 as a 14-article supplement to the American Journal of Clinical Nutrition [Volume 104, Number 3(S)]external link disclaimer. 
     
    • Workshop 1—April 22–23, 2014
      The first meeting focused on the assessment of iodine intake from both foods and dietary supplements.
    • Workshop 2—July 22–23, 2014
      The second meeting addressed laboratory assessments of iodine status, including assessments related to thyroid function, particularly in relation to the needs of high-risk groups (pregnant and lactating women, infants, and young children).
    • Workshop 3—September 22–23, 2014 
      The third meeting addressed iodine status concerns in pregnant women, the potential impact of suboptimal status on pregnancy outcomes and child development, and suitable study designs for evaluating and improving iodine status in regions with differing levels of risk and among various high-risk groups (infants, adolescent girls, women of reproductive age, lactating women, and older adults).
  • 2013 Iodine Symposium
    ODS held a symposium during the American Society for Nutrition's annual meeting at Experimental Biology 2013. This symposium summarized the results of recent clinical trials that have evaluated the efficacy of iodine supplementation in populations at greatest risk of iodine deficiency. A summary was published in Advances in Nutrition.
    • Swanson CA, Pearce EN. Iodine insufficiency: a global health problem? Adv Nutr 2013;4:533-5. [PubMed abstract]
  • 2011 Iodine Meeting
    This ODS-sponsored meeting brought together iodine experts and representatives from the National Institutes of Health (NIH), other agencies of the Department of Health and Human Services, and Health Canada, to begin developing an NIH iodine research initiative.. Participants identified research needed to inform the development of new dietary reference intakes for iodine. A summary was published in the Journal of Nutrition.
    • Swanson CA, Zimmermann MB, Skeaff S, Pearce EN, Dwyer JT, Trumbo PR, et al. Summary of an NIH workshop to identify research needs to improve the monitoring of iodine status in the United States and to inform the DRI. J Nutr 2012;142:1175S-85S. [PubMed abstract]
  • 2011 Iodine Expert Panel Meeting (Biomarkers of Nutrition for Development [BOND] Program):
    ODS has supported the BOND program, led by the NIH Eunice Kennedy Shriver National Institute of Child Health and Human Development, to harmonize the processes for choosing biomarkers to use for research, program development and evaluation, and evidence-based policies. The Iodine Expert Panel was one of the first groups that the BOND program convened, and ODS staff participated in the panel’s 2011 meeting. The resulting report [Rohner F et al, 2014] summarizes the state of the science and identifies critical research priorities.
  • 2008 Experimental Biology Symposium, Methyl Donors, Iodine, and DHA---Is Maternal Supplementation Beneficial?:
    ODS participated in this symposium during the American Society for Nutrition’s annual meeting at Experimental Biology in April 2008. The symposium addressed questions of whether pregnant and lactating women in developed countries would benefit from higher intakes of nutrients through food or dietary supplement sources. A paper by ODS Senior Nutrition Research Scientist, Mary Frances Picciano, and Michelle McGuire reviewed the current use of dietary supplements in pregnant and lactating women in North America, pointed out the paucity of data on dietary supplement intakes by this population, and drew attention to iodine as a nutrient with intake shortfalls that potentially could be addressed through dietary supplement usage: