Limited evidence suggested that iron supplementation produced a small improvement in cognitive development but had no effect on physical growth .
CONCLUSIONS : In 2 to 5 year olds , daily iron supplementation increases hemoglobin and ferritin .
There is a concerning lack of data on the effect of iron supplementation on clinical ly important outcomes including anemia , ID anemia , ID , and cognitive development .
BACKGROUND AND OBJECTIVES : Iron deficiency ( ID ) is the most common cause of anemia worldwide .
The prevalence is highest among preschool-aged children .
Iron is widely administered to children with or at risk for ID , but evidence of benefit among 2- to 5-year-old children has not been evaluated by systematic review .
We summarize the evidence for the benefit and safety of daily iron supplementation with regard to hematologic , growth , and cognitive parameters in 2 to 5 year olds .
Iron and zinc supplementation improves indicators of vitamin A status of Mexican preschoolers.
BACKGROUND The coexistence of multiple micronutrient deficiencies is a widespread public health problem in many regions of the world . Interactions between zinc deficiency and vitamin A metabolism have been reported but no longitudinal studies have evaluated the effect of iron deficiency on vitamin A. OBJECTIVE The objective of this study was to investigate the effect of supplementation with iron , zinc , or both on vitamin A and its metabolically related proteins retinol binding protein ( RBP ) and transthyretin . DESIGN The study was a longitudinal , double-blind , placebo-controlled trial in which 219 rural Mexican children aged 18 - 36 mo were r and omly assigned to receive 20 mg Zn/d , 20 mg Fe/d , 20 mg Zn/d plus 20 mg Fe/d , or placebo . RESULTS Six months after supplementation , plasma retinol increased in all supplemented groups . Compared with placebo , zinc supplementation was associated with significantly higher plasma retinol and transthyretin but the increase in RBP was not significant . Iron supplementation significantly increased plasma retinol , RBP , and transthyretin . Supplementation with zinc plus iron significantly increased plasma retinol but not RBP or transthyretin .  Children deficient in zinc , iron , or vitamin A ( as indicated by nutrient plasma concentration ) at the beginning of the study had a significantly greater increase in retinol than did children with adequate nutrient status . CONCLUSIONS Supplementation with zinc , iron , or both improved indicators of vitamin A status . The results of this study agree with previous observations of a metabolic interaction between zinc and vitamin A and suggest an interaction between iron and vitamin A metabolism
Limited evidence suggested that iron supplementation produced a small improvement in cognitive development but had no effect on physical growth .
CONCLUSIONS : In 2 to 5 year olds , daily iron supplementation increases hemoglobin and ferritin .
There is a concerning lack of data on the effect of iron supplementation on clinical ly important outcomes including anemia , ID anemia , ID , and cognitive development .
BACKGROUND AND OBJECTIVES : Iron deficiency ( ID ) is the most common cause of anemia worldwide .
The prevalence is highest among preschool-aged children .
Iron is widely administered to children with or at risk for ID , but evidence of benefit among 2- to 5-year-old children has not been evaluated by systematic review .
We summarize the evidence for the benefit and safety of daily iron supplementation with regard to hematologic , growth , and cognitive parameters in 2 to 5 year olds .