A statement, published in the June issue of Pediatrics states “Many women of reproductive age in the United States are marginally iodine deficient, perhaps because the salt in processed foods is not iodized,” write Walter J. Rogan, MD, from the National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, and colleagues.
“Iodine deficiency, per se, can interfere with normal brain development in their offspring; in addition, it increases vulnerability to the effects of certain environmental pollutants, such as nitrate, thiocyanate, and perchlorate. Although pregnant and lactating women should take a supplement containing adequate iodide, only about 15% do so.”
The production of thyroid hormone requires adequate iodine intake. Untreated hypothyroidism in infancy may affect cognitive development, and if severe, it may cause serious, permanent brain damage.
Iodized table salt helped prevent iodine deficiency before the main source of salt in the US diet became processed foods, which are not prepared with iodized salt. The prevalence of iodine deficiency has risen along with consumption of processed foods, and about one third of pregnant women in the United States are now iodine-deficient.
Breast-feeding mothers should take a supplement containing at least 150 μg of iodide and should use iodized table salt to achieve a combined daily iodide intake of 290 to 1100 μg.
Urine testing for iodine deficiency may be indicated for vegan mothers or for those who do not consume dairy or fish.
To avoid potential interference with iodide transport and to prevent methemoglobinemia in their infants, breast-feeding mothers should avoid excess nitrate, which is found in some private well water.