A positive effect of iron supplementation on the IQS of iron deficient children

To examine possible effects of iron supplementation on the intelligence of young adolescents, iron supplements and placebos were given daily for 16 weeks to two matched groups of 208 and 205 12–15-year-olds. Iron status before the trial began was assessed by the measurement of serum ferritin and haemoglobin levels. In the sample considered as a whole, the iron supplementation had a small but nonsignificant effect on IQ, but those who were iron deficient, with serum ferritin levels of 12 ng/ml and below, showed a statistically significant IQ gain of 5.8 IQ points, as compared with a matched control group given placebos.