Many pregnant and breastfeeding women in the U.S. may be lacking iodine in their diets, which is an essential element for their babies' brain development, according to a new policy statement from the American Academy of Pediatrics (AAP), "Iodine Deficiency, Pollutant Chemicals, and the Thyroid: New Information on an Old Problem," published in the June 2014 Pediatrics (published online May 26).
Most of the salt in the U.S. diet is from processed foods, and that
salt is not iodized. As consumption of processed foods has increased, so has the level of iodine deficiency, with about one-third of pregnant women in the U.S. being deficient.
Pregnant and lactating women should take supplements that contain adequate levels of iodine, but only about 15 percent of this group does so. Adequate iodine intake is needed to produce thyroid hormone, which is critical for brain development in children. Severe, untreated
hypothyroidism in infancy has serious, permanent effects on the brain, and milder cases of hypothyroidism can also affect a child's
cognitive development. In addition, iodine deficiency in a mother increases both mother and child's vulnerability to the effects of certain environmental pollutants -- most notably thiocyanate (found in cruciferous vegetables and
tobacco smoke) and nitrate (found in certain leafy and root vegetables). Perchlorate, an environmental pollutant found in about four percent of
public drinking water supplies and in a few foods is an additional concern.
In the policy statement, the AAP recommends iodine supplementation for breastfeeding mothers and should be considered for some other women of childbearing age, and recommends that young infants not be exposed to tobacco smoke or drinking water with excess nitrate. The AAP calls for better and more accurate labeling of supplements to reflect the actual content of iodide. The statement also calls on the federal government to complete a national primary drinking water regulation for perchlorate, and calls on state and local governments to enact clean-air and
smoke-free legislation and ordinances.