Development of an Evidenced-based Iodine Food Fact Sheet for use in the UK

Abstract

Background: An adequate intake of iodine is vital before and during pregnancy as iodine is required for fetal brain development [1]. We have shown that a low iodine status in UK pregnant women is adversely associated with cognition in the child [2]. The UK is now classified as mildly iodine deficient but there is very little information about iodine in nutritional advice given to the UK public. This study aimed to produce an evidenced-based food fact sheet on iodine.  Methods: The iodine concentration of a range of UK foods was estimated from number of studies, including those from the Food Standards Agency (FSA). Average values per portion of white fish (cod, haddock, plaice and coley), oily fish (mackerel, kippers, salmon, sardines, trout, pilchards and herring) and shellfish (scampi, mussels, cockles and prawns) were taken from data reported in a UK Total Diet study. The iodine concentration of dairy products was calculated from the appendix of the 2008 FSA report and these values (split by summer and winter because of the seasonal difference in milk-iodine content) were used, together with recent values of the iodine content of organic milk [3] . Results: The iodine concentration of a range of food items is shown in Table 1. A double-sided fact sheet was produced that covered information on iodine requirements, iodine-containing nutritional supplements, and advice against excessive iodine intake.  Discussion: Information on dietary source of iodine is available in other countries (e.g. New Zealand) but to date has not been available in the UK. The construction of an evidence-based fact sheet is therefore an important step in improving knowledge of the importance of iodine in the UK diet. The main dietary iodine sources are dairy products and fish and dietitians should be aware of iodine deficiency in those who omit these sources, especially women of childbearing age. Kelp supplements should not be used owing to their high iodine content and risk of excess.  Conclusion: The iodine factsheet produced by this study has now been published by the British Dietetic Association as part of their “Food Fact Sheet” series and should be a useful resource for both dietitians and the public.