The World Health Organization considers iodine deficiency to be “the single most important preventable cause of brain damage” worldwide. The effect of severe iodine deficiency is well documented. Pregnant and nursing mothers have increased requirements and are thus a vulnerable group. Iodine is a key component of thyroid hormones that are critical for normal development of the brain and nervous system in utero. There is little data on the effect of mild- and moderate iodine deficiency. Results from the Norwegian Mother and Child cohort (n = about 62,000) shows that only 22% of the participants had an iodine intake, estimated from food frequency questionnaire, that meets the recommendations of WHO / UNICEF / ICCIDD. Urine samples from a sub-sample (n = 119) confirmed suboptimal iodine status. The results are consistent with recent data from a NIFES study of about 100 women from the municipality of Fjell, which reviled suboptimal iodine status both in pregnancy and three months after birth. Preliminary results from the study Little in Norway, where NIFES measured the iodine status in approximately 1 000 pregnant from across the country, is also consistent with these investigations. Dairy products is highlighted as the main source of iodine for the participants in the Norwegian Mother and Child cohort, while lean fish is the food group that has the highest Iodine levels.
The recommendation is to eat 2-3 dinner meals with seafood weekly. National data indicates that the intake is lower than recommended. Few studies have studied the effects of mild- and moderate iodine deficiency on child development. In an observational study from the UK, however, researchers found a negative correlation between low maternal iodine status in pregnancy and various developmental domains (including IQ) in children at 8-9 years of age. In an earlier publication from the same population researchers found similar conclusion when they assessed the association between maternal seafood intake during pregnancy and children’s development. In this article, the positive effect of seafood was explained by the fatty acids EPA and DHA, while the latest publication suggests that the effect of an adequate intake of seafood during pregnancy are more complex, and that the high iodine levels in seafood may also be important. Based on this knowledge, there is a need for an intervention study where pregnant consume cod regularly over a longer period and where the children are followed up over time.