Introduction: Optimization of iodine intake aims to prevent the irreversible damage that iodine deficiency (ID) can cause in the central nervous system during its development, as well as thyroid disorders that can be induced by both ID and excessive micronutrient intake. The Spanish legal regulation stipulates that iodized salt (IS) must contain 60 mg of iodine per kg of salt (60 ppm), allowing a tolerance of ±15%. The aim of this study is to address the iodine content of different commercially available IS in Spain.
Methods: 162 different IS lots from 51 different product presentations were collected from Spanish food stores in Andalusia, Aragon, Asturias, Balearic Islands, Catalonia, Madrid and Basque Country between 2014 and 2016. Iodine concentration in these samples was assessed by HDL-chromatography (HPLC).
Results: The mean (S.D.) and median (P25P75) iodine concentration for these 162 samples was 61.2 (19.7) and 59 (5070) μg I/g salt, respectively. Iodine concentration dispersion was mainly attributable to iodide-fortified IS (n=67). The analysis of these fortified IS revealed that 67.2% of them had iodine levels out of the legal threshold (5169 μg I/g salt), whereas only 43.2% of the iodate-fortified IS (n=95) were outside this limit (P<0.05).
Conclusions: IS, having an average 60 μg I/g salt, is an important alimentary source of iodine in Spain. The use of iodate instead of iodide for the fortification of the salt allows a greater proportion of IS with iodine concentration within the legal limits. Public Health and Consumer Affairs authorities should closely monitor IS production processes and eventually check IS sale points in order to homogenize the iodine content of commercially available IS packages and thereby optimize their intake by the population.
20 - 23 May 2017
European Society of Endocrinology