Iron Needs in Endurance Runners

Gretchen Buskirk, LAT, ATC
Graduate Assistant Athletic Trainer
NC State University

There are many different factors that contribute to the performance of athletes, especially cross country runners. Athletes can enhance their performance with proper nutrition, hydration, and flexibility. All of these factors are directly controlled by the athlete. However, other factors, like iron levels, that also enhance or hinder performance, are indirectly controlled by the athlete. A low iron level is one of the most common conditions among athletes, especially endurance athletes. This can result in a decrease in red blood cells called anemia. Females are more likely than males to become anemic. Although there are various causes of this condition, the diagnosis and treatment are the same.

Iron

Red blood cells comprise the majority of human blood. These cells transport oxygen from the lungs to the various tissues of the body and transport carbon dioxide from the tissues back to the lungs. A protein called hemoglobin is part of these red blood cells. Iron plays various roles in the human body, including immune function, energy metabolism, and work performance. Iron is essential for hemoglobin function because each oxygen molecule that is transported travels with an iron molecule. In all, humans hold about four grams of iron, with the majority of the iron with hemoglobin. Some iron is lost in waste products. Women also lose more iron with menstruation; therefore, need more dietary iron than men.

Causes of Anemia

The human body continually recycles iron in hemoglobin from old red blood cells and uses it to make new red blood cells. If the loss of iron is greater than the body's ability to recycle iron or to absorb iron from the diet, an iron deficiency may develop. There are multiple forms of anemia, including sickle-cell, foot strike or runner's anemia, and iron deficiency anemia. Of these, iron deficiency anemia is the most common among athletes. In order for anemia to occur, the amount of hemoglobin is decreased, red blood cells are too small, or ferritin concentration is low. Ferritin is a protein in the blood that binds and stores iron.

The clinical signs and symptoms of iron deficiency include a decline in the athlete's performance, ice craving, fatigue, lethargy, difficulties in concentration, and the inability to exercise at previous levels of intensity. If an athlete experiences any of these symptoms, it is imperative that the athlete be seen by advanced medical personnel, including a doctor.

Once the athlete seeks advanced medical attention, blood lab work, especially serum ferritin, is the most accurate way to diagnosis anemia. The size of the red blood cells and the average volume of individual cells are other blood tests needed to analyze iron levels.

Management

Once the diagnosis of anemia has been determined, there are many different treatment options available to the athlete. First, the dietary iron absorption needs to be analyzed. A proper diet of iron-rich foods, including red meat, spinach, beans, shrimp, and artichoke, is an important first step in the management of anemia. The Recommended Dietary Allowance, or the suggested amount of iron consumed through foods, for iron for adult females is 18 milligrams and 8 milligrams for adult men. However, these values need to balance iron consumption with iron loss in the body, which will be vary among individuals.

Iron supplementation is another treatment option for anemia. There are many types of iron supplements, both over-the-counter and prescription, that assist in correcting the anemic conditions. The specific dosage and type of supplementation is an individualized treatment that should be discussed by the medical doctor and athlete and parents.

Helpful Hints

  • Regardless of if it is through food or supplementation, iron is better absorbed in the body with vitamin C and hindered by the presence of calcium. Therefore, the iron is better absorbed with consuming orange juice and not milk or yogurt. Caffeine and tea also hinder the absorption of iron.

  • It takes approximately four to six months to return hemoglobin levels in the blood back to normal, depending on the stage of deficiency. So although an athlete has started iron supplementation and an adequate diet, it will take about 120 days to appear in the blood itself.

  • Vegetarians are typically at risk for developing iron deficiency anemia. Although red meats are an excellent source of iron, there are many non-animal sources, including spinach and beans, which a vegetarian can consume. It is vital for such athletes to ensure adequate iron consumption through these foods. A multi-vitamin or iron-fortified foods, especially cereal, may assist a vegetarian athlete in consuming adequate iron.

  • If an athlete is unsure of his or her dietary iron consumption, a registered dietitian will be able to properly analyze the athlete's diet and give sound dietary recommendations to enhance the iron levels.

  • Anemia is not accurately diagnosed without blood work that analyzes the iron storage, iron levels, and red blood cell size.

In conclusion, iron is an essential component of the blood that aids in many important functions in the body, including oxygen transport to the tissues. For an athlete to maintain optimal performance, iron levels need to remain high. If athletic performance begins to decline and the athlete feels lethargic, low iron levels may be the cause and it is crucial to seek advanced medical care to assess this issue accurately. If diagnosed anemic, dietary changes and possibly iron supplementation can help return the iron levels to normal range.