A SECOND OPINION
This space is for our physician members to speak their minds freely on both medical or non-medical issues of the day and respond to the opinions of others . The GLMS Editorial Board reserves the right to choose what will be published . Please note that the views expressed in A Second Opinion or any other article in this publication are not those of the Greater Louisville Medical Society or Louisville Medicine .
Be Aware of Iron
by ELIZABETH A . AMIN MD
This is my rant about the confusion surrounding the recommended daily value ( RDV ) for oral iron intake in post-menopausal women , particularly late post-menopausal women who have neither iron deficiency anemia nor hereditary hemochromatosis nor chronic disease . Intake recommendations for iron and other nutrients are provided in the Dietary Reference Intakes ( DRIs ) developed by the Food and Nutrition Board ( FNB ) at the Institute of Medicine ( IOM ) of the National Academies ( formerly National Academy of Sciences .) 1
I have taken a daily multivitamin with minerals since I was pregnant with our first child . For much of my adult life , I was often too busy to eat properly . My daily vitamin was my guarantee of my continuing robust good health . Centrum has always been my go-to brand . Over the decades the formulas have changed a little , particularly the added minerals . When I thought it appropriate , I switched from Centrum Adults to Centrum Silver Women 50 +. I was surprised to see that the amount of iron in this formula was 8mg but listed as 44 % of the RDV ( see table 1 ). I called the 1-800 number to ask why the listing was such . The person I spoke to listened politely as I pointed out that 8mg iron was 100 % RDV for women who were no longer menstruating and that eating a healthy diet – including meat – would bring the total above that level . Finally the person responded by saying that the formula was set by their physicians , but she would raise my concern with her supervisor . I never heard
Table 1 : Recommended Daily Allowances ( RDAs )* for iron Age Male Female Pregnancy Lactation
Birth to 6 months
0.27mg
0.27mg
7-12 months 11mg 11mg 1-3 years 7mg 7mg 4-8 years 10mg 10mg 9-13 years 8mg 8mg 14-18 years 11mg 15mg 27mg 10mg 19-50 8mg 18mg 27mg 9mg 51 years and older
8mg 8mg **
* It would appear that RDAs , RDVs and also DVs ( Daily Values ) noted on food labels are interchangeable acronyms for recommended daily intake ,
** This will vary depending on age at time of cessation of menstruation .
back . To this day , the amount of iron in Centrum Silver Women 50 + remains 8mg listed as 44 % RDV .
If the human body excreted the excess iron that it does not need there would not be an issue . However , iron is used very efficiently in the human body . It is metabolized and reused . Very little is excreted in the urine , feces and skin . The average human adult body contains approximately 3 – 4 grams of elemental iron . At least 60 % is in hemoglobin ( the protein in red blood cells that transfers oxygen from the lungs to the tissues ). Iron is also present in the protein
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