Iodine is a micronutrient required for thyroid hormone synthesis, which regulates metabolism, growth, and development. Thyroid hormone production can be altered by iodine deficit or excess. The degree, timing, and length of exposure all have an impact on newborn development. Because of the increased thyroid hormone turnover during infancy, the iodine demand is very high. 

Breastfed newborns rely on iodine from human milk. However, the quantity of iodine in breast milk is influenced by mother iodine consumption. Many nations’ diets are deficient in iodine, and iodine fortification of salt prevents deficiency. However, the availability of iodized salt differs by country. Epidemiological statistics show that iodine consumption varies greatly across nursing mothers, babies, and toddlers worldwide, ranging from insufficient to excessive. For a study, researchers presented an overview of existing knowledge and recent breakthroughs in understanding the iodine diet and its relationship with thyroid function in nursing mothers, babies, and toddlers. They covered the risk factors for iodine deficiency and the impact of specific intervention efforts on these vulnerable populations. They emphasized the need for accurate definitions of an adequate iodine diet and further data measuring the risk of moderate iodine deficit for thyroid diseases during the first two years of life. 

Reference:academic.oup.com/edrv/article/43/3/469/6430367