Although the UK has historically been considered to have adequate iodine levels, there is growing concern that this is no longer the case, particularly among women of childbearing age and pregnant women. Iodine is now much more prevalent in the UK than it was in the previous 50 years. However, it remains a nutrient that many medical professionals are still unaware of, sometimes overlooking it (Jiang et al., 2018).
T4 and T3 thyroid hormones are produced with the help of iodine, which is essential for regulating metabolic rate, growth, and development. Iodine needs to be consumed in sufficient amounts throughout pregnancy for the fetus’s brain and nervous system to develop normally, which depends on the action of thyroid hormones. This discussion supports the claim that not using iodized salt harms the UK population.
Iodine consumption for adults (over 12 years) is recommended at 150 ÎĽg per day (MacMullan et al., 2019). The daily iodine requirement increases from 150 to 250 ÎĽg during pregnancy and breastfeeding. Because the amount of iodine in breast milk reflects the quantity of iodine consumed by the mother and brain development continues in the postnatal period, it is crucial to provide an ample supply of iodine throughout lactation (Woodside & Mullan, 2020).
Excess iodine should be avoided, as it may adversely affect thyroid hormone production. The safe upper limit for adults (over 12 years) and pregnant women is approximately 600 g/day (Dineva et al., 2021). However, if thyroidal adjustment to a low iodine supply has already occurred, those with chronic iodine insufficiency may react negatively to levels lower than this. As such, people with thyroid disorders should consult their doctor.
The “iodine deficiency disorders” are mainly brought on by insufficient thyroid hormone production. Low iodine intakes lead to the development of goiter, and this thyroid hyperplasia is an adaptive response to the low iodine supply by increasing the thyroid’s capacity to store iodine. Cretinism, a disorder characterized by severe learning deficits and deafness, is known to be caused by a severe iodine deficiency (Wainwright & Cook, 2018).
The implications of mild-to-moderate iodine deficiency are more concerning in the UK and other affluent nations. Only two iodine invasion studies in expectant women in areas with moderately severe iodine deficiency have been performed, and both found that iodine intake improved child cognition. Regrettably, neither study was randomized or placebo-controlled, so the results should be interpreted with caution.
References
Dineva, M., Rayman, M. P., & Bath, S. C. (2020). Iodine status of consumers of milk-alternative drinks v. cows’ milk: Data from the UK national diet and nutrition survey. British Journal of Nutrition, 126(1), 28-36.
Jiang, H., Powers, H. J., & Rossetto, G. S. (2018). A systematic review of iodine deficiency among women in the UK. Public Health Nutrition, 22(06), 1138-1147.
McMullan, P., Hamill, L., Doolan, K., Hunter, A., McCance, D., Patterson, C., Smyth, P., Woodside, J. V., & Mullan, K. (2019). Iodine deficiency among pregnant women living in Northern Ireland. Clinical Endocrinology, 91(5), 639-645.
Wainwright, P., & Cook, P. (2018). The assessment of iodine status – populations, individuals and limitations. Annals of Clinical Biochemistry: International Journal of Laboratory Medicine, 56(1), 7-14.
Woodside, J. V., & Mullan, K. R. (2020). Iodine status in UK–an accidental public health triumph gone sour. Clinical Endocrinology, 94(4), 692-699.