 Universal salt iodization USI is the most effective means to ensure optimal population iodine status and prevent iodine deficiency. In countries where USI is well implemented it is generally assumed that iodine requirements of infants are covered through breast milk. As infants wean from breast milk, at the age of 4-6 months, iodized salt programs likely contribute little to their iodine intakes. Home-prepared complementary foods have low native iodine content and pediatric guidelines recommend no extra salt be given to infants during the first year making the dietary sources of iodine limited. Weaning infants may therefore be particularly vulnerable to iodine deficiency and its effects. 