What are the Side Effects of Iron Supplements in Children?

side effects of iron supplements

Iron is important to enable healthy physical and cognitive development in infants and children. Researchers recently examined the literature concerning the risks and benefits of iron supplementation in African children and the side effects of iron supplements.


Iron deficiency is common in Sub-Saharan children and carries serious potential risks. In fact, as many as 63% of African pre-school aged children are anemic and up to half of those cases are directly due to a deficiency of dietary iron. There has been much research on the safest and most effective way to fortify the diets of these children with iron, however there are many side effects of iron supplements that create difficulties.

This review of the side effects of iron supplements in Sub-Saharan African infants and children who had iron-deficiency anemia found affects on both the gut microbiome and diarrhea. The review summarized the results of studies that provided infant and children with complementary foods that were fortified with iron using a micronutrient powder (MNP) and/or oral iron supplementation. The researchers deemed this as an effective strategy to improve iron deficiency anemia within these age groups which were between infancy to pre-school years. The strategy was implemented based on earlier studies having revealed that these infants and children had high rates of anemia partly due to a lack of sufficient iron in complementary foods. Furthermore, the bioavailability of iron was not sufficient in the complementary food given after the weaning period for the infants and children.

As published in the American Journal of Clinical Nutrition, the intervention strategies produced large amounts of colonic iron from an increase in absorption from the high iron doses. Based on other studies reviewed by the researchers, they found that the effects of iron supplements and iron fortified foods had affected and caused gut microbiome irregularities and diarrhea in infants and children. Other studies allowed the researchers to recognize that the micronutrient powders with iron supplements could increase the risk of diarrhea, but prebiotics and other supplements like lactoferrin could moderate the side effects of iron supplements and enable better results for iron absorption. Past studies have revealed that the gut microbiome could be adversely affected because of the colonic iron creating a barrier for these bacteria to thrive and could cause E. coli increase causing pathogenic inflammation in the gut.

As such, safer measures would need to be implemented to ensure the prevention of the mal-absorption of iron. With safer formulas for micronutrient powders and iron-containing supplements, infants and children could have maximized absorption of iron. This would prevent the adverse effects of the gut that leads to diarrhea. Studies on maintaining iron levels in infants and children may need to be further explored and the addition of probiotics and some other substances like lactoferrin could aid in maintaining iron levels and preventing gut inflammation and diarrhea. Further, from the very early years, infants and children need to be well nourished to ensure good physical and cognitive development.

Written by Dr. MòNique J. Grant Coke, DNP, MPH, BSN, Medical Writer

Reference: Paganini, D. & Zimmermann, M. (2017). Effects of iron fortification and supplementation on the gut microbiome and diarrhea in infants and children: a review. Am J Clin Nutr doi: https://doi.org/10.3945/ajcn.117.156067.