Iron and Endurance Athletes
by Jeff Rocco MD
Iron is one of the most abundant mineral on earth and is essential to normal human physiology. About 2/3 of the body’s iron is found in hemoglobin, the protein in red blood cells that carries oxygen to cells. An adequate supply of iron is necessary for the body to produce hemoglobin and red blood cells. If too little iron is available, fewer and/or smaller RBC’s are produced, leading to decreased oxygen carrying capacity of the blood. This is called iron deficiency anemia and can cause fatigue, poor work capacity, and decreased immunity.
Endurance athletes depend on efficient oxygen delivery to working muscles, so even mild anemia can have deleterious effects on performance. Some hypothesize that iron deficiency, even without anemia, can impair endurance. However, one review showed that in seven of 8 studies that although iron supplementation does increase iron stores, as measured by ferritin levels, no increase in performance was found unless hemoglobin also increased. In the eighth study, there was an unexplainable drop in endurance performance in the control group which confounded the results. (Garza 1997)...
