much iron as those who eat
meat, to ensure that enough iron
is absorbed in their bodies.
Bioavailability is not the only
consideration. Red meat, poultry, fish, oysters, and egg yolk
offer the most iron per gram of
food consumed. But in terms
of calories, spinach, kale, and
Swiss chard, along with whole
grains, beans, and lentils, often
provide more iron per calorie
consumed than meat. All of
these food products are nourishing and good for you, and which
is “best” may just be a matter
Also, what foods you pair
with other foods can make a big difference,
as shown in Table 1.
Some of the foods that contain iron also
inhibit its bioavailability. Spinach, long
considered a powerful iron-rich food, is
also rich in polyphenols—antioxidants
which can bind with iron to inhibit iron
absorption. The effect may be small, but
this is another part of the body’s iron balancing act, making it next to impossible for
a healthy person to over-absorb iron from
the diet, no matter how much salad, or
even steak, one consumes. The body will
take what it needs, adding extra if you had
a recent bloody nose, and store or dispose
of the rest.
A proper balance is key. A few grams of
iron in the heart, the brain, the pancreas,
and especially the blood will keep you
healthy and strong. And it is amazingly
easy to get iron in meals as varied as, say,
steaks and burgers, chicken and salad, or
a vegetarian or vegan dish.
U.S. nutritionists recognize that a normally varied diet, especially if it contains
some meat and plenty of vitamin C, balances out these different factors and usually delivers all the iron a body requires.
But if you eat a steady diet of mac-and-cheese or live on milk and yogurt, you may
have cause for concern.
Not enough iron?
What happens if the body does not get
enough iron? Studies have shown that
young women with low amounts of iron
in their bodies perform poorly, compared to
healthy women, in tasks ranging from school
performance to Army basic training.
Low levels of iron in the blood
can lead to iron-deficiency anemia, in which red blood cells
shrink in size and quantity.
Energy levels decline and muscles weaken.
Hearts race and headaches pound. Skin and
nails become dry and turn yellow, and hair
So is more better? Should you
load up on iron to become an
Ironman or Ironwoman? Actually, no. Too much iron stored in your
body makes you more vulnerable to serious
conditions. Excess iron—which is more
common in older people—can lead to cancer
Examples of food
Effect on iron-rich foods
Vitamin C Lemon juice,
Significantly increases the
bioavailability of non-heme iron,
because vitamin C prevents the
formation of insoluble compounds and
helps convert iron(III) into iron(II).
Calcium Milk, cheese,
Is the only known substance
that may inhibit the absorption
of both kinds of iron.
Table 1. When you pair a food product rich in iron with food products that have vitamin C or calcium,
you may have unexpected effects.
or a heart attack and can possibly
accelerate Alzheimer’s disease.
A genetic condition called
hemochromatosis causes the
body to absorb and hold too
much iron, which overtaxes
major organs. Another possible reason for over-absorbing
iron can be eating too much
red meat, because the body’s
checks and balances on iron
absorption apply mostly to the
Amazingly, symptoms of too
much iron are similar to those
of too little iron, which were
mentioned earlier. Even more
amazing, the main “cure” of
hemochromatosis is removing
blood from the body, which means the 17th-
and 18th-century doctors who prescribed
bloodletting treatments for their patients were
not always wrong.
Also, iron supplements can be overdone.
Iron pills that once looked like a popular candy
became a leading source of iron poisoning in
children—so much so that special regulations
require warning labels on iron pills to differentiate them from those that look like M&M’s.
But if iron imbalance does not affect you,
then why should you care? Because everyone
is harmed when a significant portion of the
world’s population is too ill from iron deficiency to work and sustain themselves and
their families. Because everyone is affected
when children are prevented from fully developing, due to lack of a common element.
Because we are all ironmen and ironwomen at
Teens Health: Anemia. Nemours Foundation: http://
[accessed Nov 2016].
Iron-Deficiency Anemia. American Society of
Anemia/ Iron-Deficiency.aspx [accessed Nov
Dayan, F. E.; Dayan, E. A. Porphyrins: One Ring in
the Colors of Life. American Scientist, May–June
[accessed Nov 2016].
Gail Kay Haines is a science writer and book
author from Olympia, Wash. Her most recent
ChemMatters article, “No Smartphones, No TV,
No Computers: Life without Rare-Earth Metals,”
appeared in the October/November 2016 issue. S H U T T