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 .
Hematological effect of supplementing anemic children with vitamin A alone and in combination with iron.
Ninety-nine anemic children aged 1 - 8 y were divided into four groups . Each group was supplemented for 2 mo with vitamin A , iron , vitamin A plus Fe , or a placebo .  Clinical , hematological , and Fe biochemical evaluations were performed at the beginning and end of the study . Vitamin A supplementation produced significant elevations in the serum levels of retinol , blood hemoglobin , hematocrit , erythrocytes , serum Fe , and percent transferrin saturation ( % TS ) and had no effect on total Fe binding capacity ( TIBC ) or serum ferritin . Fe supplementation did not affect serum retinol . However , it improved hematological and Fe nutrition indicators , including TIBC and serum ferritin . The simultaneous administration of vitamin A and Fe result ed in a better response of serum Fe and % TS than when the supplement consisted only of vitamin A or Fe alone . Vitamin A benefits hematological condition and Fe 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 .