Intelligence quotient (IQ) is a measure of intellect derived from standardized testing with a median, or normal, score of 100. Studies have shown that iodine deficiency is correlated with a reduced IQ.

Researchers studied three groups of pregnant women and measured the IQs of their children. All three groups were supplemented with 200 mcg of iodine — which is an amount that is slightly lower than the recommended daily intake for iodine.

The first group was supplemented at 4 to 6 weeks of gestation; group two was supplemented at 12 to 14 weeks of gestation; and group three was not supplemented until after delivery.

The results were astounding. The IQ of the infants in group one was normal — averaging about 101.

The IQ of group two was 92. Just a short delay — 8 weeks gestation — in iodine supplementation was associated with a significant decline in the children’s IQ. Group three, supplemented only after pregnancy, had the lowest average score: 87.

This study showed that the longer that iodine was delayed during pregnancy, the lower the IQ in the newborn.

This is not the only study to show a correlation with lower IQ levels related to iodine deficiency. A meta-analysis of 18 studies of children and adolescents found that iodine deficiency was associated with a 13.5-point lower IQ score in children and adolescents.

In fact, the same results have been found around the world in multiple cultures.