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Our research found that people partially adapt to iron supplementation 
by reducing their nonheme iron, but NOT heme iron absorption from food.

Body stores are controlled by absorption rather than excretion. 

The take-home message is that men and post-menopausal women SHOULD NOT
take iron supplements.

My research group has also published research showing that iron absorption
is much less from a lacto-ovo-vegetarian diet (Am J Clin Nutr
1999;69:944-952) and that men eating a diet with highly absorbable iron
(generous in meat, Vitamin C-containing foods, and refined grains) adapt to
absorb less iron, while those on a poorly absorbable iron diet (much lower
amounts of meat and Vitamin C, with plenty of whole grains, legumes and tea)
adapt to absorb more (Am J Clin Nutr 2000;71:94-102). (Summaries are
available on the MEDLINE database). 

As with the supplement study, adaptation occurred for nonheme, but NOT 
the heme form of iron in food.

We need to be aware of possible problems with both iron deficiency and iron
excess, and the importance of a balanced diet that helps people obtain
adequate iron without excessive iron. 


In conclusion, vegetarian diets are a healthy approach. Vegetarian
diets are commonly associated with lower body iron stores, and this may
increase the risk of deficiency for child-bearing-aged women, but decrease
the risk of excess for men and postmenopausal women, especially those with a
genetic predisposition to accumulate iron. For people with excessive body
iron stores (which can be determined by your doctor) donating blood is much
more efficient thaN dietary changes to lower body iron.

This represents my personal opinions as a nutrition researcher and is in 
no way an official position of the USDA.

Janet R. Hunt, Ph.D., R.D.
USDA-ARS Grand Forks Human Nutrition Research Center
PO Box 9034 University Station,
Grand Forks, ND 58202



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ADAPTATION IN IRON ABSORPTION: DAILY IRON SUPPLEMENTATION DECREASES
ABSORPTION EFFICIENCY OF NONHEME, BUT NOT HEME IRON, FROM FOOD 
AND SLIGHTLY INCREASES SERUM FERRITIN IN NORMAL VOLUNTEERS

   Author(s):
          ROUGHEAD ZAMZAM K
          HUNT JANET R

   Interpretive Summary:
          There are two types of iron in our diet(heme and nonheme).
          Although we know that the body can adapt the absorption of iron
          depending on its needs and how much iron is in the food, it is
          not clear if it handles these two types of iron differently.
          This iron supplementation study was designed to test for
          differences in adaptation of heme and nonheme iron absorption.
          Heme and nonheme absorption from a meal of hamburger, french
          fries, and milk shake were measured before and after 12 weeks of
          supplementation. Also, serum ferritin which indicates iron
          stores, was measured with supplementation and 6 months after
          supplementation was stopped. 
          In conclusion , we found that with daily iron
          supplementation, healthy individuals adapted to decrease their
          nonheme, but not heme iron absorption from food. This indicates
          that the body handles heme and nonheme iron differently and
          that there may be more control over the absorption of nonheme
          iron than heme iron. 


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