Sports ShortsIron in Athletes: is there a role for measuring ferritin levels? Greg Walker, MD, FAAP

G U I D E L I N E S F O R P E D IAT R I C IA N S

Iron is the essential mineral the body utilizes for oxygen transportation and energy production and is required for the production of hemoglobin and myoglobin, found in red blood cells and muscles, respectively. Iron is absorbed from the diet in two main forms, free iron and iron from animal products. Free iron is found in foods such as beans, spinach, fortified cereals and dried fruits whereas animal-based iron (containing heme) is found in meat, poultry and seafood. Animal-based iron is more easily absorbed than free iron. Iron in the body is tightly controlled by a constant balance between iron from our diet, iron breakdown mainly through breakdown of red blood cells and iron recycling within the body. Most people, including athletes, have normal levels of iron, however endurance athletes and female athletes, are more susceptible to iron deficiency. Iron discussions tend to focus on anemia, however this article focuses on iron deficiency without anemia.

How is iron deficiency defined?Most of the iron in the body is contained in red blood cells, so iron deficiency has traditionally been linked to anemia. However, there is a spectrum of iron deficiency which begins prior to a drop in hemoglobin levels. Unfortunately, there is less agreement about this ‘pre-anemic’ state. Ferritin is responsible for binding extra iron in the body and effectively serves as the body’s iron storehouse and a low ferritin level is the most widely accepted way of identifying iron deficiency without anemia.

How is iron related to athletic performance?Iron is essential for proteins that generate energy during aerobic exercise. Thus iron deficiency tends to primarily affect endurance athletes. When individuals have iron deficiency, they tend to ‘overuse’ the anaerobic energy production pathways put to use during short bursts of exercise, such as sprinting, weight lifting, throwing, etc. Anaerobic pathways tend to be easily drained creating a sense of fatigue or lack of energy. In other words, an athlete who performs short bursts of exercise may not be affected by low iron stores, but endurance athletes (runners, cyclists, rowers, etc.) may notice the drop in energy during prolonged exercise.

What are the symptoms of iron deficiency in athletes?

• Fatigue• Lack of energy• Apathy• Worsening performance throughout the sports season

Should athletes be screened for iron deficiency?There is a lack of consensus for iron deficiency screening in all youth athletes. While some suggest routine screening of asymptomatic patients, particularly endurance female athletes, there is no compelling evidence to support this practice. However, symptomatic patients may certainly benefit from laboratory evaluation to rule out iron deficiency and anemia.

Can iron supplementation improve iron deficiency?Several studies have shown that both increasing iron within the diet and utilizing supplemental iron can improve exercise capacity and endurance. Primary prevention of iron deficiency centers around dietary strategies to increase iron-containing foods because the typical American diet is relatively poor in iron content. Particularly, vegetarians often have lower iron stores given the decreased absorption of free iron compared with animal-based iron. Supplementation, in the form of an iron pill, is generally considered when the athlete has a low ferritin level. Supplementation ranging from 20-100 mg of elemental iron per day for 6-12 weeks has been shown to improve serum ferritin concentrations.

What foods are rich in iron?• Red meat• Poultry• Pork• Seafood

Summary and recommendationsIron deficiency in the youth athlete is a relatively rare condition but is more prevalent in female athletes and endurance athletes. Indicators such as fatigue, worsening exercise performance or lack of energy can be signs of an iron deficient state. Ferritin is an acceptable marker of iron storage – low levels may indicate iron deficiency. Iron supplementation along with dietary modification to increase iron consumption have been shown to increase iron stores and improve performance. It is important to note that there is a paucity of research on iron supplementation for individuals without defined iron deficiency. It is not recommended to supplement with iron pills or make specific changes to one’s diet in the absence of known iron deficiency. Use of vitamin C (ascorbic acid) during supplementation can improve absorption. Side effects of supplementation include nausea, upset stomach, and constipation. When discussing iron supplementation, considerations for the aforementioned risks and benefits should be discussed.

This information is available on the Ohio Chapter, American Academy of Pediatrics’ website at www.ohioaap.org

• Beans• Spinach and other dark leafy greens• Dried fruit, such as raisins and apricots• Iron fortified cereals

www.ohioaap.org

Sports ShortsIron in Athletes: is there a role for measuring ferritin levels? Greg Walker, MD, FAAP

G U I D E L I N E S F O R PA R E N T S

Iron is the essential mineral the body uses for oxygen transportation and energy production. Iron is absorbed in the diet in two main forms, free iron and iron from animal products. Free iron is found in foods such as beans, spinach, fortified cereals and dried fruits whereas animal-based iron (containing a molecule called heme) is found in meat, poultry and seafood. Animal-based iron is more easily absorbed than free iron. Iron in the body is tightly controlled by a constant balance between iron from our diet, iron breakdown mainly through breakdown of red blood cells and iron recycling within the body. Most people, including athletes, have normal levels of iron, however endurance athletes and female athletes, are more likely to suffer from iron deficiency. Iron discussions tend to focus on the state of being anemic, or not having enough red blood cells. However this article will focus on the iron deficient state without anemia.

How is iron deficiency defined?Most of the iron in the body is contained in red blood cells. Because of this, iron deficiency has traditionally been linked to having too few red blood cells, also known as anemia. However, there exists a spectrum of iron deficiency which begins prior to a drop in hemoglobin levels. Unfortunately, there is less agreement about this ‘pre-anemic’ state. Ferritin is the molecule that is responsible for binding extra iron in the body and serves as the body’s iron storehouse. Fortunately, there is a simple laboratory test that can measure one’s ferritin level. This level, when low, is the best way to identify iron deficiency without anemia.

How is iron related to athletic performance?Iron is essential for proteins that generate energy during aerobic exercise. Thus iron deficiency tends to primarily affect endurance athletes and can be seen as a drop in energy during prolonged exercise.

What are the symptoms of iron deficiency in athletes?

• Fatigue• Lack of energy• Apathy• Worsening performance throughout the sports season

Should my child be screened for iron deficiency?There is a lack of consensus for iron deficiency screening in all youth athletes. While some suggest routine screening of asymptomatic patients, particularly endurance female athletes, there is no compelling evidence to screen athletes

without symptoms of iron deficiency. Generally, it is accepted that endurance athletes with the above symptoms may benefit from laboratory evaluation to rule out iron deficiency and anemia.

Can iron supplementation improve iron deficiency?Several studies have shown that both increasing iron within the diet and utilizing supplemental iron (taking an iron pill) can improve both exercise capacity and endurance. It is important to start by increasing dietary intake of iron-containing foods because the typical American diet is relatively poor in iron content. Particularly, vegetarians often have lower iron stores given the decreased absorption of free iron compared with animal-based iron. Supplementation with an iron pill is generally considered when the athlete has a low ferritin level. Supplementation ranging from 20-100 mg of elemental iron per day for 6-12 weeks can improve serum ferritin concentrations.

What foods are rich in iron?• Red meat• Poultry• Pork• Seafood

Summary and recommendationsIron deficiency in the youth athlete is a relatively rare condition but is more prevalent in female athletes and endurance athletes. Indicators such as fatigue, worsening exercise performance or lack of energy can be signs of iron deficiency. Ferritin is an acceptable marker of iron storage – low levels may indicate iron deficiency. Supplementation with iron pills along with dietary modification to increase iron consumption can increase iron stores and improve performance in these individuals. It is important to note that there is little research on iron supplementation for individuals without defined iron deficiency. It is not recommended to supplement with iron pills or make specific changes to one’s diet in the absence of known iron deficiency. Use of vitamin C (for example, drinking orange juice) during supplementation can improve absorption. Side effects of supplementation include nausea, upset stomach, and constipation. When discussing iron supplementation, considerations of the risks and benefits should be discussed.

This information is available on the Ohio Chapter, American Academy of Pediatrics’ website at www.ohioaap.org

• Beans• Spinach and other dark leafy greens• Dried fruit, such as raisins and apricots• Iron fortified cereals