Iodine
The effects of iodine deficiency are known as the Iodine Deficiency Disorders and include cretinism, stunting, and loss of IQ. Universal Salt Iodisation – USI – is the principal public health strategy to ensure adequate population iodine intakes, and great progress has been made in optimising iodine intakes around the world through USI in the last decades. Monitoring and surveillance of USI is critical for its success, and support is given by the Iodine Global Network, the US CDC’s EQUIP scheme, UNICEF and EUThyroid, amongst other valuable resources. Date of preparation: January 2019
Contribution:
- Jessica Farebrother, Sandra Hunziker, Maria Andersson, Dr Jessica Farebrother PhD from the OpeN-Global team
- Sandra Hunziker MSc, Human Nutrition Laboratory, ETH Zurich, Zurich, Switzerland: http://www.humannutrition.ethz.ch
- Dr Maria Andersson PhD, OpeN-Global Expert Partner
Importance of iodine for health
Iodine is an essential micronutrient required for the synthesis of thyroid hormone. The effects of iodine deficiency are known as the Iodine Deficiency Disorders and include hypothyroidism, goitre, loss of IQ and cretinism (1-3). However, iodine excess can also be harmful; optimal iodine intakes require a careful balance between deficiency and excess, and there is a U-shaped relationship between iodine intake and thyroid function (4-7).
Thyroid hormone maintains vital cellular functions and controls many metabolic processes in the body, and is crucial for optimal growth and development from conception onwards. The developing foetus relies on adequate iodine and thyroid hormone from the mother to accelerate myelination of the nerves in the brain and central nervous system, and a deficiency in iodine during this critical period can lead to a loss of up to 10 IQ points (8). The foetus and infants are vulnerable to effects of iodine deficiency, and pregnant and lactating women are high-risk groups for iodine deficiency due to increased requirements (9-13). During lactation, women must consume enough iodine to provide for their infants as well as themselves, until lactation is complete (14, 15).
Universal Salt Iodisation (USI) is the primary public health strategy to ensure adequate population iodine intakes (16, 17). Monitoring and surveillance of iodine fortification policy is critical for its success.