Benefit and risk assessment of iodization of household salt and salt used in bread and bakery products. Opinion of the Panel on Nutrition, Dietetic Products, Novel Food and Allergy of the Norwegian Scientific Committee for Food and Environment

Request from the Norwegian Food Safety Authority: Following a report from the National Nutrition Council calling for actions to secure adequate iodine intake in the population, the Norwegian Food Safety Authority requested the Norwegian Scientific Committee for Food and Environment (VKM) to conduct a benefit- and risk assessment of iodization of household salt and industrialised salt in bread. VKM addressed the request: VKM appointed a project group consisting of members of the Panel on Nutrition, Dietetic Products, Novel Food and Allergy and Panel on Contaminants to answer the request. The Panel on Nutrition, Dietetic Products, Novel Food and Allergy has reviewed and revised drafts prepared by the project group and finally approved the benefit- and risk assessment This benefit and risk assessment is based on 1) established knowledge about health consequences from severe iodine deficiency, 2) systematic literature review of the evidence for health consequences of mild to moderate iodine deficiency, 3) literature review of studies on adverse health effects from excessive iodine intakes to re-evaluate existing tolerable upper intake levels (ULs), 4) evaluation of estimated iodine intake levels in different population groups in Norway compared to established dietary reference values, specifically estimated average requirement (EAR) and UL, and finally 5) an estimation of the effect of different scenarios of increasing iodization levels in household salt and salt in bread on iodine intake levels in different population groups compared to the established dietary reference values EAR and UL. For the purpose of this benefit and risk assessment of iodization in household salt and salt in bread, risk may be understood as risk of adverse health effects related to too high or too low iodine intakes. Benefit may be understood as reduction or avoidance of adverse health effects related to too high or too low iodine intakes. For iodine, this is a challenging maneuver, as the gap between too low and too high intakes is narrow. The project group conducted two systematic literature reviews. One was performed to evaluate the evidence for the impact of mild- to moderate iodine deficiency on neurodevelopment, thyroid function and birth outcomes, the other to evaluate the evidence for adverse health effects from excessive iodine intake to possibly re-evaluate the existing tolerable upper intake levels. Current evidence for adverse health effects of iodine deficiency: Severe io