and Chronic Fatigue
When we work and play hard, we often pay for it with next-day
fatigue. Fatigue and lethargy are also common complaints that
can result from many medical conditions and sometimes their treatment.
But one of the more well-known and common causes of chronic tiredness
Iron, which is mostly found in the red blood cells, is needed
to courier oxygen to cells to perform their functions. Iron-deficiency
anemia, the most common form of anemia, occurs when there is a
lack of this mineral in the body. There are many causes for iron
depletion: blood loss, red blood cell damage, low dietary intake,
or poor absorption.
Although rates of iron-deficiency anemia are relatively low
in the Unites States, where many people eat an iron-rich diet,
it is still a concern among young children and pregnant women,
whose iron requirements are high.
That's why the Centers for Disease Control and Prevention recommends
periodic screening for anemia among infants, preschool age children
and pregnant women and non-pregnant women during the reproductive
years. And iron-deficiency rates are higher among women in general,
and in highly trained athletes.
Fortunately, most iron-deficiency anemia can be treated with
dietary modifications or over-the-counter iron supplements taken
under the guidance of a physician.
Below, anemia researcher John Beard, a professor in the department
of nutritional sciences at Pennsylvania State University, explains
the causes, detection methods and treatment for iron deficiency
What is iron deficiency anemia?
Anemia is the result of an individual being in a negative iron
balance. The deficiency of iron over a long period of time will
lead to an insufficient amount of iron going to bone marrow, which
is where red blood cells are produced. Over a long enough period
of time, people who are iron deficient will end up a lower than
optimal concentration of hemoglobin, which is the iron-rich protein
in red blood cells that carries oxygen to the tissues, and a lower
number of red blood cells circulating in the bloodstream. Iron
goes into all the tissues in the body and is required for functioning
of basically all tissues because it's essential for the production
of the energy currency for cells. In order to have muscles contract
or neurons fire or anything like that, cells need to expend chemical
What are some of the signs and symptoms
of low iron status?
What's frequently mentioned is a feeling of lethargy and lack
of energy. But it's quite clear that, in the more severe stages
of iron deficiency, there's a decrease in physical work capacity;
the muscles will not work as well or as long. And it's been proven
many times in exercise studies, for instance, that the maximal
aerobic capacity is diminished in people who are iron deficient.
Endurance capacity is also affected.
The problem is that most people who are mildly iron deficient
don't know it. It's like most hypertensives: Unless they are really
hypertensive, they don't know that they're hypertensive. So most
people are just made aware of the need for iron supplements after
they've been diagnosed by the family doctor, or perhaps they tried
to donate blood and they were rejected because they were anemic.
What are some of the long-term consequences
of low iron?
More recently, our research group and others have been spending
a lot of our investigative energy looking at the effect of iron
deficiency on brain function and brain development. Evidence tells
us that infants who are iron deficient from about 12 to 24 months
have a developmental delay, and there is new evidence that there
is an irreversible change in brain functioning.
How is anemia diagnosed?
There are many different tests for anemia. The hemocrit measurement
is a measure of how many red cells you have in a particular volume
of blood. The hemoglobin test is a measure of the amount of this
oxygen-carrying protein in a particular volume of blood. But these
tests don't distinguish between different forms or causes of anemia.
The most common secondary test measures ferritin, which is a
storage protein for iron. The amount of this protein that's found
in blood is proportional to the amount of storage in the liver
and spleen, the main storage sites. And so, when we measure the
amount of ferritin in blood, if it's low we oftentimes conclude
that the person is iron-deficient anemic.
The one problem is that the ferritin value is very strongly
affected by whether somebody has an infection. There are certain
proteins that are elevated whenever we have an acute infection
or even sometimes a longer-term infection, or an autoimmune disease
Then there is another test but, this is generally only available
in research labs. This new marker protein — transferrin
receptor protein — gives us an indirect signal that non-red
blood cells are iron-deficient. And so that gives us an indirect
signal that we have iron deficiency that is occurring in cells
in the tissues.
Finally, there is another measure, which is called protoporphyrin.
And that's a nifty little measurement, because that tells us the
availability of iron to newly developing red cells in bone marrow.
If there's not enough iron going to the bone marrow, the protein
inside the red cell is formed without the iron molecule.
And so with those five measurements, one can have a pretty high
level of confidence when diagnosing somebody with iron-deficiency
anemia or not.
Why are women at higher risk for iron
The predominant risk factor is the imbalance between losses of
iron, which primarily occurs through blood loss, and the intake
of iron, which is, in our society, predominantly in meat. So any
imbalance between these two things would put somebody at risk.
As a result, women who have heavy menstrual flows are more likely
to be iron-deficient. And women may have an increase in requirements
because of pregnancy or blood loss at delivery.
The American diet is generally able to meet iron requirements
for most of the population, except for pregnant women. That's
why we've been prescribing iron pills in pregnancy for a good
25 or 30 years now. The deficiency is due to the expansion of
the maternal blood volume, and fetal and placental growth. Of
course, the mom gets to recover part of that iron in the first
two or three weeks after delivery because her blood volume contracts
back to what it was in the prepartum phase.
Birth weight and gestational age of the infant seem to affect
maternal iron status, at least the severity of anemia. It's very
difficult to keep women from getting somewhat anemic, but to avoid
severe anemia is highly desirable.
When else does the demand for iron
It increases during periods of really rapid growth. For instance,
the adolescent growth spurt in boys increases requirements. They
can essentially double within a 12- to 18-month timeframe. Girls
go through maturation at a slower rate than boys do, but they,
of course, are acquiring menstrual flows, so iron requirements
dramatically increase in preadolescent to adolescent girls.
Other situations that increase risk are post-surgical situations
where there was blood loss. Any medical condition that causes
a high rate of blood loss such as bleeding ulcers would increase
risk. Not so much in our culture, but elsewhere in the world,
roundworms, hookworms and other worms that cause loss of blood
out of a gastrointestinal tract, would be a reason to suspect
a negative iron balance.
Why might athletes be at increased
Repeated high levels of exercise cause the red cells to break
apart at an earlier age than they normally would. Most of our
red cells will stay in circulation for about 120 days. With highly
trained athletes — and it seems to be not dependent on sport
— the red cell lifespan may decrease by as much as 20 percent
or 30 percent. Instead of red cells being around for 120 days,
they're really maybe only around for 95 or 100 days. We recycle
most of that iron, but there is some fraction that we lose from
our body every day. The higher the rate of red cell turnover,
the higher the rate of expected loss of iron.
The other factor is that heavily trained athletes tend to diet
frequently. And they are, a lot of times, not meat-eaters, and
that leads to a relatively lower iron intake and a higher iron
How do infants meet the requirement?
Iron deficiency in early infancy used to be a big problem in the
United States 25, 30 years ago, but it really is not any more.
We've pretty well taken care of the problem with the introduction
of iron-fortified formulas and then iron drops for infants who
are being exclusively breast-fed. We recommend that mothers who
exclusively breast-feed their infants start providing iron drops
at about six months of age in order to increase their iron intake
because breast milk has a very low concentration of iron.
How is iron-deficiency anemia treated?
Treatment depends on the severity of the iron deficiency. Dietary
approaches are often effective, but I think most clinicians will
go with over-the-counter supplements.
Over-the-counter iron supplements are usually in a form that
is absorbed efficiently. The ferrous sulfate forms are quite absorbable.
Many people tolerate the delayed or slow-release forms of iron
supplements much better than the normal regular release dose.
These forms are gradually dissolved in the stomach over the course
of the whole day, so gastrointestinal upset and distress is not
quite as prominent as it is with some of the other forms. I would
tend to not recommend multivitamins that contain iron, because
there's a real question as to whether or not the iron that's in
a multivitamin is really absorbable.
Whenever we do studies where we're doing iron repletion, or
replenishment, we always use ferrous sulfate in a low-dose once
or a twice a day. And that seems to be quite effective in treating
mildly iron-deficient anemic women. Within three months, they
are iron-repleted. We use the lowest over-the-counter dose that
you can pick up at the pharmacy, which is about 125 mg of ferrous
sulfate; the actual amount of iron that's there is 39 mg.
What foods are high in iron?
Any of the meats are higher in iron: fish, poultry, red meats.
They all have forms of iron that are more absorbable than the
forms of iron that are in most of our vegetables or grains. That's
because they also contain compounds that inhibit the absorption
of iron. So the net gain is not very large. So vegetarians are
at greater risk for iron deficiency anemia, but they can avoid
it if they are very diligent about how they plan their menus.
The average American diet probably has an efficiency of iron
absorption of only somewhere between 5 percent and 7 percent.
So of that 15 mg to 18 mg of iron that's actually in your daily
diet, only 5 percent to 8 percent of that actually gets across
the gastrointestinal cell into the blood. It might be a little
bit higher in some other places in the world where iron deficiency
is more common. The body physiology is set up so that if you are
iron deficient, you try to absorb more iron.
Would you recommend that people buy supplements only if they
have been advised to by a physician? I do, though a lot of women
know whether they have higher than what is perceived to be normal
menstrual blood losses. And they will self-prescribe an iron supplement
and I think that makes a lot of sense.
Are there any risks associated with
the iron supplements?
At low doses, most people do not get upset stomachs or constipation.
But at progressively higher doses, a higher proportion of individuals
would report gastrointestinal distress. And it's one of the biggest
problems with measuring compliance to iron supplements in pregnancy
studies, for instance.
There is an approach that we and other people have been trying
to use in the last number of years, which is called intermittent
iron therapy. That involves taking an iron supplement every three
days instead of every day. There have been a number of studies
that tell us that, as long as you're not treating somebody that
has a real high iron requirement like in pregnancy — in
pregnancy, daily iron does seem to be better — a low dose
every three days or even two times a week seems to do a quite
a good job.
Are there people who should not take
Any sort of high dietary iron intake is dangerous for people with
a genetic disease called hemochromatosis. It is probably the most
prevalent blood genetic disorder that exists. Reportedly, it's
just in people of Anglo-Saxon ancestry. And so it's prevalent
in northern Europe, of course, Australia and United States.
Perhaps one in 20 white Anglo-Saxon individuals in the United
States has inherited one of their sets of genes for this defect.
And the defect is in regulating iron absorption across the gastrointestinal
tract. And so, an individual with hemochromatosis can't limit
the amount of iron they absorb.
Reference Source 104