Iron supplementation is almost always necessary for a female distance runner; I suggest a B complex with iron.  There are other vitamins and minerals that we don’t get enough of in a normal diet. When you look at RDA requirements for these vitamins and minerals, the minimum is always given.  For instance, in a multi-vitamin, 60 mg of vitamin C is the amount generally used.  This is the amount you need to not get scurvy. Taking much more is not only beneficial, but needed.  This is one of the vital catalysts for proper iron absorption.  What I am saying is generally the RDA recommended dosage for most vitamins and minerals are far too low, especially for endurance athletes.

From the research that I have seen, a serum ferritin score of around 30 is the minimum that you would want to see.  Scores in the 40’s and 50’s and higher are desired.  There is a genetic syndrome called hemochromatosis where the body is in a state of iron overload.  This is why you need to be tested before taking an iron supplement so you are not in danger of this syndrome. 

  • Iron, one of the most abundant metals on Earth, is essential to most life forms and to normal human physiology. Iron is an integral part of many proteins and enzymes that maintain good health. In humans, iron is an essential component of proteins involved in oxygen transport.

  • Almost two-thirds of iron in the body is found in hemoglobin, the protein in red blood cells that carries oxygen to tissues.

  • Iron is also found in proteins that store iron for future needs and that transport iron in blood. Ferritin is the protein and when these stores get low iron cannot be used properly.

  • There are two forms of dietary iron: heme and nonheme. Heme iron is derived from hemoglobin, the protein in red blood cells that delivers oxygen to cells. Heme iron is found in animal foods that originally contained hemoglobin, such as red meats, fish, and poultry. Iron in plant foods such as lentils and beans is arranged in a chemical structure called nonheme iron. Heme is the easiest to absorb.

  • Iron absorption refers to the amount of dietary iron that the body obtains and uses from food. Healthy adults absorb only about 10% to 15% of dietary iron, but individual absorption is influenced by several factors, such as other vitamins, such as C which help absorption.

Iron supplementation is indicated when diet alone cannot restore deficient iron levels to normal within an acceptable time-frame. Most female runners fall into this category.  Supplements are especially important when an individual is experiencing clinical symptoms of iron deficiency anemia. The goals of providing oral iron supplements are to supply sufficient iron to restore normal storage levels of iron and to replenish hemoglobin deficits. When hemoglobin levels are below normal, physicians often measure serum ferritin, the storage form of iron. A serum ferritin level less than or equal to 15 micrograms per liter confirms iron deficiency anemia in women, and suggests a need for iron supplementation.  This 15 mg score is for a sedentary person.  This score would be far too low for an endurance athlete.

The amount of iron absorbed decreases with increasing doses. For this reason, it is recommended that most people take their prescribed daily iron supplement in two or three equally spaced doses. For adults who are not pregnant, the CDC recommends taking 50 mg to 60 mg of oral elemental iron (the approximate amount of elemental iron in one 300 mg tablet of ferrous sulfate) twice daily for three months for the therapeutic treatment of iron deficiency anemia. However, physicians evaluate each person individually, and prescribe according to individual needs.

When to take iron?  Most runners will take iron before bed for convenience.  I have found this not to be advantageous for maximum absorption.  Take your iron on an empty stomach with some form of vitamin C preferably between breakfast and lunch, or lunch and dinner, or both.

Supplemental iron is available in two forms: ferrous and ferric. Ferrous iron salts (ferrous fumarate, ferrous sulfate, and ferrous gluconate) are the best absorbed forms of iron supplements.  You should also use a vitamin C catalyst along with the iron supplement.  I also recommend taking a B-complex.  The B vitamins work with iron for proper red blood cell growth among a whole host of reactions that will help your running.


WHERE TO TEST? Econolabs is a cheap way to get tested. We suggest ALL athletes should be tested.  If you go to the doctor, remember, you want the serum ferritin test!


Recommended Reading:

"Iron Level Upkeep for Runners

Low ferritin and iron deficiency anemia in distance runners

“Are you suffering from an iron deficiency?”

Iron Depletion

“4 Things Every Coach, Parent, or Female Athlete Should Know About Running and Puberty”

“Iron Deficiency, Anemia and Endurance Athletes”