Iron supplementation improves mental development score modestly .
This effect is particularly apparent for intelligence tests above 7 years of age and in initially anaemic or iron-deficient anaemic subjects .
There is no convincing evidence that iron treatment has an effect on mental development in children below 27 months of age or on motor development
OBJECTIVE To evaluate the effect of iron supplementation on  mental and motor development in children through a systematic review of r and omised controlled trials ( RCTs ) .
Randomised study of cognitive effects of iron supplementation in non-anaemic iron-deficient adolescent girls
BACKGROUND Up to 25 % of adolescent girls in the USA are iron deficient . This double-blind , placebo-controlled clinical trial assessed the effects of iron supplementation on cognitive function in adolescent girls with non-anaemic iron deficiency . METHODS 716 girls who enrolled at four Baltimore high schools were screened for non-anaemic iron deficiency ( serum ferritin < or = 12 micrograms/L with normal haemoglobin ) . 98 ( 13.7 % ) girls had non-anaemic iron deficiency of whom 81 were enrolled in the trial . Participants were r and omly assigned oral ferrous sulphate ( 650 mg twice daily ) or placebo for 8 weeks . The effect of iron treatment was assessed by question naires and haematological and cognitive tests , which were done before treatment started and repeated after the intervention . We used four tests of attention and memory to measure cognitive functioning . Intention-to-treat and per- protocol analyses were done . FINDINGS Of the 81 enrolled girls with non-anaemic iron deficiency , 78 ( 96 % ) completed the study ( 39 in each group ) . Five girls ( three control , two treatment ) developed anaemia during the intervention and were excluded from the analyses . Thus , 73 girls were included in the per- protocol analysis . Ethnic distribution , mean age , serum ferritin concentrations , haemoglobin concentrations , and cognitive test scores of the groups did not differ significantly at baseline . Postintervention haematological measures of iron status were significantly improved in the treatment group ( serum ferritin 27.3 vs 12.1 micrograms/L , p < 0.001 ) . Regression analysis showed that girls who received iron performed better on a test of verbal learning and memory than girls in the control group ( p < 0.02 ) . INTERPRETATION In this urban population of non-anaemic iron-deficient adolescent girls , iron supplementation improved verbal learning and memory
Iron supplementation improves mental development score modestly .
This effect is particularly apparent for intelligence tests above 7 years of age and in initially anaemic or iron-deficient anaemic subjects .
There is no convincing evidence that iron treatment has an effect on mental development in children below 27 months of age or on motor development
OBJECTIVE To evaluate the effect of iron supplementation on  mental and motor development in children through a systematic review of r and omised controlled trials ( RCTs ) .