The recommended daily iron intake is 10 grams per day for men and 15 grams for pre-menopausal women. Due to iron losses during menstruation, women need more iron than men, but because they eat fewer calories, women generally take in less iron than men, often failing to meet their needs. Since iron is essential to the formation of red blood cells, iron deficiency often results in anemia, characterized by persistent fatigue.
There is evidence that anemia is more common among endurance athletes, and especially runners, than among the general population, possibly due to iron losses incurred through sweating and other exercise-related mechanisms. In most cases, iron deficiency is easily avoided through adequate intake of iron-rich foods including tuna, chicken and beef. However, in some cases iron supplementation is deemed medically necessary. Iron is one supplement that should only be taken under a doctor’s supervision, because high iron levels in the body are toxic. Have your iron levels checked annually and take iron pills if your doctor says they’re needed.