Modelling the contribution of iodised salt in industrially processed foods to iodine intake in Macedonia

Abstract

Evidence from the 1950s showed that Macedonia was iodine deficient. After the introduction of mandatory universal salt iodisation, the country saw a steady increase in iodine intake and decline in goitre prevalence, earning iodine-deficiency free status in 2003. Iodine status assessments in 2007 and 2016 showed adequate iodine intake among school age children (median urinary iodine concentration of 241 μg/L and 236 μg/L respectively). Macedonia participated in piloting the Iodine Global Network Programme Guidance on the use of iodised salt in industrially processed foods to better understand potential iodised salt intake from processed foods. One objective of implementation was to identify the need, opportunities, and required actions to strengthen the processed food component of the national salt iodisation policy. Data from the 2017 Household Consumption and Expenditure Survey (HCES) was used to determine household salt consumption, to identify widely-consumed, salt-containing industrially processed foods, and estimate typical daily intake of these foods. Their estimated contribution to iodine intake was estimated based on their salt content and the percentage of food industry salt that is iodised. Although the study has limitations, including a relatively small selection of foods, the results indicate potential iodine intake from iodised household salt and iodised salt in the selected foods of nearly 300% of the Estimated Average Requirement and over 220% of the Recommended Nutrient Intake for adults. This was approximately 50% of the tolerable safe Upper Level for iodine intake. The study confirmed high daily salt intake (11.2 grams from household salt only). Successful salt reduction would be expected to reduce iodine intake, however, modelling with 10% and 30% reduction implied this is unlikely to put any population group at risk of deficiency. It is recommended that implementation of salt iodisation and salt reduction policies are harmonized, alongside continued regular iodine status monitoring for different population groups.

Fig 1. Contribution of household salt and iodised salt in selected processed foods to estimated current iodine intake, in relation to the EAR and RNI for iodine.

The values for iodine intake are based on knowledge of current iodisation practices (100% household salt and 94% food industry salt iodised). Note that the tolerable upper level (UL) for iodine intake of 600 μg iodine is not shown on this chart.

Fig 2. Potential impact of successful salt reduction on iodine intake from household salt and processed food salt (10% and 30% reduction scenarios) in relation to the EAR and RNI for iodine.

Current (100% household salt iodised and 94% industry salt iodised) iodine intake and estimated iodine intake for 10% and 30% salt reduction scenarios.