THURSDAY, June 17 (HealthDay News) -- As Americans decrease their salt consumption, thyroid experts worry that some may obtain too little iodine.

"Iodized salt is an important source of dietary iodine in the U.S. and worldwide. Iodine, essential for the synthesis of thyroid hormones, is obtained solely through diet," several members of the American Thyroid Association wrote in a letter published June 10 in the New England Journal of Medicine.

Iodine helps prevent thyroid conditions such as goiter and neonatal iodine deficiency. Iodized salt has been sold in the United States since the 1920s, but Americans' iodine levels have decreased 50 percent over the past three decades, the experts noted.

Overall, Americans still receive sufficient iodine, but research suggests that many pregnant women may be iodine-deficient. Iodine is essential for proper synthesis of thyroid hormones, which are critical to normal infant brain development and to prevent neurodevelopmental and neurobehavioral problems.

While they agree with calls for reduced salt consumption in order to improve heart health, the ATA members "recommend that all producers of commercially prepared foods -- accounting for up to 70 percent of all salt consumed in the U.S. -- use iodized salt, a step not currently practiced by commercial food manufacturers. Any decrease in salt intake should not cause a reduction in dietary iodine intake."

The ATA recommends that women take 150 micrograms of iodine supplements daily during pregnancy and breast-feeding, and that all prenatal vitamin/mineral preparations contain 150 micrograms of iodine.

More information

The American Thyroid Association has more about iodine deficiency.