Infant iron supplementation guidelines require reevaluation amid health risks, study finds

25 Oct 2022 --- A US-based team of researchers from the University of California is revealing that the rate of iron supplementation in infants may actually be harmful and should be reevaluated to prevent injuries, adverse reactions and possible death.

The study authors state that infants are highly susceptible to both iron deficiency (ID) and iron deficiency anemia (IDA). This condition can cause uncorrectable problems with cognition and neurodevelopment.

Once those problems occur, the condition of ID or IDA can be corrected, but the damage caused by the conditions can not. However, the researchers hold that an over-correction can be just as harmful.

“Concern about the harms of ID has led to the routine use of iron supplements to prevent ID,” the authors state. “Iron supplements, whether iron drops, multi-nutrient packets, fortified formula or fortified complementary foods, are effective at preventing or treating ID in most infants.” 

However, they also state, “the vast difference in iron intake – between the iron-supplemented infant and the un-supplemented infant receiving only breast milk – is important but generally underrecognized.”

Current standards
The study, published Nutrients, highlights the success of early iron supplementation endeavors but notes that standards for supplementation are outdated and need to be investigated further. 

The researchers warn that too much iron supplementation may be just as bad as none.

The study found that recommendations for infant iron supplementation by the World Health Organization (WHO) state that iron should be supplemented in areas where the rate of infant IDA is over 40%. 

Furthermore, the American Academy of Pediatrics (AAP) recommends that exclusively breastfed infants receive supplementation starting at four months old and that formula-fed infants be given only iron-fortified formulations. 

In need of recalculation
The researchers note that the Dietary Reference Intake for infants from zero to six months of age is 0.3 mg a day. This amount is based on the amount present in breast milk and the calculated iron stores in the infant’s liver.

“But most fortified formulas in the US contain 40 times more iron than breast milk,” the authors underscore. “Even after accounting for differences in bioavailability between breast milk iron and formula iron, the formula still provides around more absorbable iron than breast milk.”

“Furthermore, the AAP recommends 1 mg iron per kg [of infant weight] for daily supplementation for all exclusively or primarily breast-fed infants. Following these recommendations, an iron-supplemented 5 kg infant would receive 17 times more iron than what is provided by breast milk.”

Cure worse than sickness?
The researchers found that, even though the AAP’s and WHO’s recommendations may lower the risk of infants developing ID and IDA, the adverse effects – like the disruption of neurodevelopment, stifling the growth of organs and bones and an increased mortality rate – are just as bad, if not worse, than the ailments the supplementation is meant to prevent.

For instance, the researchers found that too much iron in the infant’s bloodstream may cause a type of cell death called ferroptosis in some infants, damaging the liver and other organs irreparably. Additionally, they found that over-supplementation could alter the infant gut microbiome at a critical period in its bacterial development. 

“Excess iron provision may delay growth and neurodevelopment and increase susceptibility to disease and infection, and it is likely that iron toxicity, mineral interactions and alterations in the gut microbiota are behind these outcomes,” the authors conclude.

Edited by William Bradford Nichols