Iodine Intake from Food and Iodized Salt as Related to Dietary Salt Consumption in the Italian Adult General Population.

Roberto Iacone,Pasquale Strazzullo,Pietro Formisano,Luigi Palmieri,Cinzia Lo Noce,Domenico Rendina,Paola Iaccarino Idelson,Andrea Di Lenarda,Sabina Sieri,Chiara Donfrancesco,Vittorio Krogh,Daniela Galeone,Ornella Russo,Paolo Emidio Macchia,Simona Giampaoli,Ferruccio Galletti

doi:10.3390/nu13103486

Abstract

Since the Italian iodoprophylaxis strategy is based on the use of iodized salt, we assessed the relationship between dietary salt consumption and iodine intake in the Italian adult population. We estimated the relative contribution given by the use of iodized salt and by the iodine introduced by foods to the total iodine intake. The study population included 2219 adults aged 25–79 years (1138 men and 1081 women) from all Italian regions, participating to the Osservatorio Epidemiologico Cardiovascolare/Health Examination Survey 2008–2012 (OEC/HES), and examined for sodium and iodine intake in the framework of the MINISAL-GIRCSI Programme. Dietary sodium and total iodine intake were assessed by the measurement of 24 h urinary excretion, while the EPIC questionnaire was used to evaluate the iodine intake from food. Sodium and iodine intake were significantly and directly associated, upon accounting for age, sex, and BMI (Spearman rho = 0.298; p < 0.001). The iodine intake increased gradually across quintiles of salt consumption in both men and women (p < 0.001). The European Food Safety Authority (EFSA) adequacy level for iodine intake was met by men, but not women, only in the highest quintile of salt consumption. We estimated that approximately 57% of the iodine intake is derived from food and 43% from salt. Iodized salt contributed 24% of the total salt intake, including both discretionary and non-discretionary salt consumption. In conclusion, in this random sample of the Italian general adult population examined in 2008–2012, the total iodine intake secured by iodized salt and the iodine provision by food was insufficient to meet the EFSA adequate iodine intake.

Highlights

The amount of iodine provided by food has proved insufficient to fulfil the physiological needs in many regions of the world, including Italy: for the prevention of iodine insufficiency and related thyroid disorders the World Health Organization (WHO) recommends fortification of food-grade salt with iodine [1,2]
We have previously reported data on salt consumption [8] and iodine intake [10] in a national sample of Italian adult population
We reported that in this national sample of adult general population examined between 2008 and 2012 a significant relationship occurred between sodium and iodine intake and that an adequate iodine intake depended on the consumption of large amounts of salt: in order of importance, this probably was a consequence of the negligible amount of iodine provided by commercially available salt-rich processed foods, by the insufficient use of iodized salt at home and by the less-than-optimal consumption of iodine rich foods

Summary

Introduction

The amount of iodine provided by food has proved insufficient to fulfil the physiological needs in many regions of the world, including Italy: for the prevention of iodine insufficiency and related thyroid disorders the World Health Organization (WHO) recommends fortification of food-grade salt with iodine [1,2]. In Italy, the legislation on iodoprophylaxis delivered in 2005 established the addition of potassium iodate (30 mg/kg) to food-grade salt and the mandatory availability of iodised salt in food shops, supermarkets, and public catering [4]. WHO recommends limiting salt consumption to less than 5 g/day [5] to prevent arterial hypertension and the increased risk of stroke, coronary heart disease, and premature death [6]. Salt consumption and iodine intake are clearly strictly interrelated dietary factors

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Discussion

Conclusion