Insufficient iodine levels during fetal development may be associated with literacy problems in childhood, claim researchers from the University of Tasmania. According to the study published in the Journal of Clinical Endocrinology and Metabolism, iodine intake must be supplemented during pregnancy to ensure adequate levels to prevent a possible neurological defect.

Iodine is present in foods, particularly foods that contain iodized salt. The iodine is absorbed into the body during pregnancy where it impacts neurological development. The smallest iodine deficiency can have a negative impact on neurological development that could last well beyond the first 10 years of life.

Standardized testing scores were used to evaluate childhood literacy. In all, 228 children were included in the study completed from 1999 to 2001. All of the children were born when mild iodine deficiency was noted in the community due to changes in the bread industry. Bread makers switched from iodized to non-iodized salt in bread recipes causing the population deficiency. When the bread makers switched back to iodized salt the deficiency disappeared.

Based on standardized testing scores, the mild deficiency caused long-term neurological side effects in offspring conceived during the time of the deficiency. According to test results, children scored lower in literacy and spelling. Math skills were not affected by the iodine shortage. Researchers theorize the auditory part of brain development was affected, thus impacting working memory. Math skills are developed in a different part of the brain, thus no impact.

Iodine deficiency in pregnancy is preventable with supplementation. Pregnant women can use iodized table salt to increase iodine intake, but many food companies also use iodized salt in recipes making deficiencies rare in westernized cultures. According to study authors, “Pregnant women should follow public health guidelines and take daily dietary supplements containing iodine. Public health supplementation programs also can play a key role in monitoring how much iodine the population is receiving and acting to ensure at-risk groups receive enough iodine in the diet.”

Source: M. Rebagliato, M. Murcia, M. Alvarez-Pedrerol, M. Espada, A. Fernandez-Somoano, N. Lertxundi, E.-M. Navarrete-Munoz, J. Forns, A. Aranbarri, S. Llop, J. Julvez, A. Tardon, F. Ballester. Iodine Supplementation During Pregnancy and Infant Neuropsychological Development: INMA Mother and Child Cohort Study. American Journal of Epidemiology, 2013; 177 (9): 944 DOI: 10.1093/aje/kws333.