Pregnant Women Should Ensure Adequate Iodine in the Diet
A team of researchers from the Childhood and Environmental Project (INMA) has recently studied the consequences of iodine supplementation in pregnancy and found that iodine nutritional status should be one of the essential nutrients monitored for optimal brain development in the growing fetus.
The research, published in the journal Epidemiology, evaluated dietary iodine sources and the content of iodine excreted in the urine of 1844 pregnant women in two Spanish provinces between 2004 and 2008. Just under half of the women received dietary iodine through salt and the remainder took multivitamins or specific supplements containing iodine. The women showed ioduria within appropriate levels for the general population, but slightly below the levels recommended for pregnancy by the World Health Organization (WHO).
Pregnant women require between 220 and 290 micrograms of iodine a day, according to the Institute of Medicine. Many brands of prenatal vitamins in the United States do not contain all of the iodine that they claim according to testing completed on over 300 brands by ConsumerLab. The findings, published in the New England Journal of Medicine, discovered 60 brands of both over the counter and prescription prenatal vitamins that did not contain as much iodine as listed on the label.
Iodine is an essential mineral for synthesizing thyroid hormones. Natural sources are found in seafood, dairy products, and bread. Much of the table salt in the United States has iodine added.
Good iodine status both before and during pregnancy is essential for the mother’s thyroid function as well as encouraging healthy brain and psycho-motor development in the child, according to Mrisa Rebagliato, lead author of the study and researcher at the INMA Project. Iodine deficiency affects more than 2 billion people worldwide, and is one of the leading causes of mental retardation. It has also been implicated in decreased fertility and increase in the risk of miscarriage or stillbirth.
"When women begin pregnancy with sufficient levels of iodine through having previously taken iodine in their diet and iodized salt, the iodine reserves in their thyroid glands are sufficient to ensure proper synthesis of thyroid hormones, and pharmacological supplements are not recommended", says the scientist.
However, “epidemiological monitoring of nutritional iodine status should be carried out on this population [pregnant women] before making any automatic recommendations about taking iodine supplements during pregnancy.”