A good friend, and
extremely talented fellow runner wrote to me recently.
Her training has been progressing slowly, and she has
been struggling with injuries. Her doctor has told her
that her iron stores are low, especially the serum ferritin.
This led me to wonder how common this is in women runners.
Iron deficiency is
widely reported in women athletes. Numerous articles state
the causes, concerns and solutions for iron deficient
athletes. Iron deficient women, due to their greater iron
needs and generally lower calorie intake, face a lifelong
"iron crisis." (Health Fitness) A women should
consume 15 -18 milligrams of iron daily. Decreased consumption
of red meat and low calorie intake explain why female
athletes have difficulty meeting the RDA of 15 mg of iron.
Surveys of female athletes show mean daily energy intakes
ranging from 1,706 to 3,572 kcal, with an average of 13
mg/d of iron. (Sports Medicine Source)
That is why poor iron
status is more common in women exercisers / athletes -
especially distance runners - than in their male counterparts.
Suzanne Eberle, author
of Endurance Sports Nutrition, discusses the difficulity
of consuming enough iron in a meatless world. She states
that even minimal deficiencies can hamper performance.
Iron forms hemoglobin and myoglobin, which carry oxygen
to the blood and muscles. Less iron means less red blood
cells, which means less oxygen, which means less energy.
Also, iron helps to combat the increased breakdown of
red blood cells due to exercise. Females are at a special
risk because of smaller reserves and losses through menstruation.
The best source of
absorbable iron is in meat. About 20 to 30 percent of
the iron in meat is absorbed, while only 2 to 8 percent
of the iron in plants can be absorbed. Incidently, heme
iron (the iron in meat) is found not only in red meat,
but in poultry (especially the dark meat), fish and seafood.
Dairy foods and eggs are not good sources, however. Vitamin
C can be added to enhance the absorption of iron. Plant
sources which provide iron include dark leafy greens,
tomato and prune juice, dried fruit, legumes, lentils,
soy foods, whole grains and wheat germ.
If you are deficient,
it is not recommended to go overboard on supplements.
Additional supplements may be necessary, but it is important
to monitor your iron levels using blood tests which look
at your hemoglobin, hematocrit, and serum ferritin (the
storage form of iron) levels. Too much iron can interfer
with the absorbtion of zinc and coppper, and can cause
constipation, as well as a deficiency in other minerals.
In Runner's World
Complete Guide to Running by Dagny Scott, she describes
the symptoms of deficiency as exteme fatigue, dizziness
and shortness of breath, which are pretty similar to exhaustion.
The iron recommendation to prevent anemia is 15 mg. of
iron a day. Athletes are not advised to exceed the 15
mg. Scott also concedes that non meat eating runners are
especially challenged on obtaining enough iron. Kristin
Clark of Pennsylvania State University reminds us that
"Not only can you now buy very lean red meat, ...in
some cases it's leaner and lower in fat than poultry."
Whatever your methods,
watch the iron intake, be alert for signs of deficiency,
try to eat the right foods and supplement when necessary.
Your race results will mirror your success.
For
additional information on iron deficiencies:
Nutrition
Check out the
review on a new nutrition
book written by Suzanne Girard-Eberle,
a certified dietician and elite endurance
athlete.
