Science You Can Use: Really? Breastfeeding for a year or more = iron deficiency

iron dropsHave you breastfed a baby past the one year mark?

If so, a new study in Pediatrics, which found an association between breastfeeding for a year or more and iron deficiency, might have you a bit alarmed.*  We thought it deserved a closer look.

In this study, researchers examined 1,647 healthy Canadian children between 2008 and 2011 when the children were on average 3 years of age, in order to see if there was an association between how long they were breastfed and the likelihood of iron deficiency and iron deficiency anemia.

They did indeed find an association, measuring about 5% for each additional month of breastfeeding, and a cumulative probability of iron deficiency of 70% for children breastfed for a year or more compared to those breastfed for less than a year. Other factors associated with low iron were younger age, higher birth, and higher daily consumption of cow’s milk.

Their conclusion: “Increased total breastfeeding duration is associated with decreased iron stores, a clinically important association warranting additional investigation.”

So let’s take a closer look.

I asked Dr. Lori Feldman-Winter for her thoughts on this study.  Dr. Feldman-Winter is Division Head of Adolescent Medicine at Cooper University Hospital, Professor of Pediatrics, and Executive Committee member of the American Academy of Pediatrics Section on Breastfeeding.  Readers of our Booby Traps series will remember that she has championed the AAP’s pediatric residency curriculum on breastfeeding.  She has also been very engaged on behalf of the Section on Breastfeeding in the debate over iron supplementation for breastfed babies.

She described this study as “problematic on many levels:”

My first point is that while they recorded and defined exclusive breastfeeding, they chose to analyze duration of any breastfeeding, regardless of how exclusive, and they only had 14% exclusive at 6 months. This leave lots of room to say that diets with mainly formula feeding are perhaps linked to iron deficiency, or if the supplementation was juice or cows’ milk then certainly this would increase the risk.

My next point is to challenge the theory that changes in ferritin in fact lead to problems with iron status. They demonstrate nicely that the iron status rebounds and that there was NO anemia. Thus, perhaps with prolonged breastfeeding there is value in stimulating hematopoiesis.

Additionally, it is not clear to me what the actual values of ferritin were, they only published changes in values, and one assumes this is change for normal range, but it’s not clear.

Other confounding variables not included were mode of delivery or complications with delivery, and addressing issues of timing of cord clamping. It is also not clear if they asked about and controlled for intake of iron supplements.

And as always, it’s important to look for industry ties in research.  One of the nine authors disclosed that he is a consultant to several pharmaceutical companies that make iron supplements and (though this is not stated in the disclosure) either currently or until recently produced infant formula.  It’s worth noting that, like the image for this post shows, some iron drops are made by formula companies.

This study is the latest in a long-running debate about iron supplementation for breastfed babies which has recently become more heated.

In 2010 the AAP began recommending iron supplementation for exclusively breastfed babies starting at 4 months of age.  That recommendation was quite controversial, and the AAP Section on Breastfeeding submitted a letter (co-authored by Dr. Feldman-Winter) challenging this recommendation when it was released.  You can read more about the research basis for the AAP recommendation, the Section on Breastfeeding’s response here.

The letter states, “Given that research has shown potential harm in infant growth and morbidity when iron supplementation is provided to iron-sufficient infants one wonders if universal iron supplementation will be deleterious to the population of developing infants who are breastfeeding exclusively.”  Their alternative to universal iron supplementation:  Delayed cord clamping at birth and screening for at risk babies at 6 months.

The subsequent 2012 AAP breastfeeding policy states only that “supplementation or oral iron drops before 6 months may be needed to support iron stores.”  But based on how the pendulum keeps swinging on this issue, this most recent study may lead to some re-evaluation of that recommendation.

This is all quite confusing to health care providers, let alone parents, and each new turn of events in this story seems to muddy the waters further.  We can only hope that close examination of the evidence and consultation with knowledgeable and breastfeeding-supportive providers will guide us to make the best decisions for our children.

What’s your experience been like with iron supplementation for your breastfed baby?

*This discussion is provided for educational purposes, and does not substitute for medical advice provided by your health care providers.  Please consult them for care suited to your individual needs.

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7 Comments | Last revised on 04/16/2013

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