To: Sujit Sheth (Hematology)
Date: Fri, Mar 5, 2004, 7:38 PM
Question: Dr. Sheth there have been numerous cases put on the WBC
recently about iron deficiency anemia in the severe states. The AAP
recommends 3-6mg/kg/d but I heard we recommend less. Can you review
the reason why that is? Thanks
Answer: The reason for this is simple. The gut normally absorbs about
a milligram of iron a day. Since it absorbs only 10% of the total
iron ingested in a day, this means that the diet should contain about
10 mg of iron in total. In conditions of iron deficiency, the iron
absorption increases to about 2 mg of elemental iron. At the same
time the proportion of iron absorbed also increases to about 20%.
In order to provide 2 mg of elemental iron, the maximum amount of
elemental iron that one could need (even assuming only 10% was being
absorbed) would be 20 mg. So there is no point giving more than that,
since it will not be abosrbed anyway. 2 mg/kg/day of elemental iron
is more than enough.
Giving more also has its disadvantages. We all know
that iron invariably causes diarrhea or constipation. the more iron
you give, the worse this will be. And of course that means that the
compliance will drop considerably.
Therefore, because it is not necessary, and because
giving the higher dose will lead to more side effects and poorer compliance,
we recommend giving no more than 2 mg/kg/day. usually in 2 doses,
a little before food is ingested, and with somthing like orange juice
which contains vitamin C which will facilitate absorption.
A sure way to assess compliance is to nonchalantly
ask in the course of the history, as to what color the stools are.
If the answer is anything but black or very dark, the compliance is
probably not very good.
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