Iodine is a micronutrient required for the production of the thyroid hormones T3 (triiodothyronine) and T4 (thyroxine) and is of particular importance for women who are pregnant and/or of child-bearing age. The general population are recommended to consume 150µg/d with this increase to 250 µg/d during pregnancy due to the important role iodine is known to have in facilitating foetal growth and neurodevelopment with deficiency linked to a range of adverse outcomes such as neurological damage e.g., reduced IQ and cretinism.
Iodine can be obtained from a plethora of dietary sources, notably that of dairy produce and fish. The findings of the most recent UK National Diet and Nutrition Survey (NDNS) reported that the UK is failing to meet the World Health Organization (WHO) criterion required for iodine sufficiency during pregnancy of 150 µg/l, with average Urinary Iodine Concentrations reported as 102 µg/l. Furthermore, dietary data highlights low consumption of iodine-rich foods such as fish and dairy products, further increasing the risk of deficiency. The Universal Salt Iodization (USI) program helps to provide iodine for the general population alongside the increased requirement during pregnancy, with over 100 countries adopting this scheme mandatorily including Australia and The Netherlands e.g., the use of iodised salt in bread/processed food. Despite this it is not mandatorily implemented in the UK, with iodized salt used on a voluntary basis; indeed, recent research has concluded that availability is just 12% across UK stores.
The Scientific Advisory Committee on Nutrition (SACN) report in 2014 adopted the stance that there was insufficient evidence to change policy regarding the use of iodized salt; however, the extent of research highlighting the impact of iodine deficiency since then evidently illustrates that despite the concerns of SACN in the UK, iodized salt can be used effectively alongside the salt reduction campaign as a suggested policy change to further promote optimal public health. Currently, it is hoped that the UK will adopt a similar approach to iodine as that of folic acid, encouraging supplementation during pregnancy alongside continuing to publicize the importance the USI program can have upon iodine deficiency.
Written by Anna Monaghan, Co-Chair IFST Student Group 2020/21
Final year PhD Researcher, Ulster University