Are breast-fed infants and toddlers in New Zealand at risk of iodine deficiency?

Nutrition. 2005 Mar;21(3):325-31. doi: 10.1016/j.nut.2004.07.004.


Objective: This study assessed the iodine status of New Zealand infants and toddlers and explored factors that might influence their iodine status.

Methods: A community-based, cross-sectional survey of 6- to 24-mo-old children was conducted in three cities in the South Island of New Zealand. Iodine status was determined by a casual urine sample. Breast-feeding mothers were asked to provide a breast milk sample for iodine determination. Caregivers collected a 3-d weighed diet record from their children to investigate associations between dietary patterns and urinary iodine excretion.

Results: The median urinary iodine concentration for the group (n = 230) was 67 microg/L (interquartile range 37-115) with 37% (95% confidence interval 30.5-43.4) of children having a urinary iodine concentration lower than 50 microg/L. When children were classified by current feeding method, those children who were currently formula-fed had a significantly higher median urinary iodine concentration (99 microg/L) than did children who were currently breast-fed (44 microg/L; P < 0.000). The mean iodine concentration in breast milk was 22 microg/L (n = 39). After multivariate analysis using estimates from 3-d diet records, only percentage of energy from infant formula was significantly associated with urinary iodine concentration (P = 0.005).

Conclusions: This study found mild iodine deficiency in a group of New Zealand infants and toddlers. Children who consumed infant formula, which is fortified with iodine, had better iodine status than did children who were currently breast-fed because breast milk contained low levels of iodine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Breast Feeding / adverse effects*
  • Breast Feeding / statistics & numerical data*
  • Child, Preschool
  • Cross-Sectional Studies
  • Diet Records
  • Female
  • Humans
  • Infant
  • Infant Nutritional Physiological Phenomena / physiology
  • Iodine / deficiency*
  • Iodine / urine
  • Male
  • New Zealand / epidemiology
  • Nutrition Disorders / epidemiology*
  • Nutritional Status / physiology
  • Regression Analysis
  • Risk Factors
  • Surveys and Questionnaires


  • Iodine