The BEST way to get any nutrient is through food sources, much more
preferable than artificial supplements. (hmmm... where to draw a parallel :)

The iron contained in meat is the most bioavailable (meaning, we can absorb
a greater proportion of the iron in meat) because 1) it has a relatively
high
ratio of grams of iron per kilogram of foodstuff, 2) there is a very
efficient transport system in the intestines for iron when it is bound to
hemoglobin (as in meat), and 3) there is some other component of meat,
called
"meat factor," that increases the amount of iron absorbed from the diet
(they
call it "meat factor" because we still don't know what the compound is).  If

a person does not eat meat (you don't have to in order to get dietary iron),

there are other foods, like beans and some green vegetables (not spinach),
that provide a reasonably high ratio of grams of iron per kilogram of
foodstuff.  The iron in non-animal sources has to be taken up from the gut
in
ionic form, a mechanism that is entirely separate from heme-iron transport
and is much less efficient.  Vitamin C increases the proportion of dietary
iron absorbed from any foodstuff.  Several foods reduce the amount of iron
you can absorb from foods.  These include phytate (a carbohydrate found in
grains, especially whole grains) and tannins (found in black teas, among
others).  Milk apparantly causes a small amount of gastrointestinal
bleeding,
which can make a person's iron status worse (thus the problem with ABM).
Artificial supplements of iron should not interfere with absorption of other

dietary iron sources when properly given.  The "more is better" idea causes
many health-care providers to give larger and larger doses of oral iron
which
only lead to more and more gastrointestinal discomfort.  Low doses of oral
iron given less frequently (every other day or even once a week) seem to
work
just as well (when one actually needs the extra iron).

By the way, hematocrit is a very poor measure of iron status or anemia,
especially during pregnancy.  During pregnancy, hematocrit should normally
drop as the mother's plasma volume expands to accomodate all the extra red
blood cells being synthesized to transport oxygen to the fetus.  A pregnant
woman can have great iron status and a low hematocrit and be just fine.

Paul Zimmer, Ph.D.