Iron Deficiencies More Common in Elite Athletes than Previously Thought

Elite endurance athletes, particularly males, are more prone to iron deficiency than previously thought, according to a team of researchers led by Prof. Jamie Burr in the Department of Human Health and Nutritional Sciences.

Training at the elite level can lead to both iron deficiency (ID), which is defined by low iron levels in the blood, and iron deficient anemia (IDA), which is characterized by both low iron and low hemoglobin levels. Hemoglobin is an iron-containing protein in red blood cells that is critical for carrying oxygen to the body’s tissues.

“In sports medicine, there is a large focus on female athletes in terms of iron deficiency problems, but [doctors and researchers] never focus on the males… even though men are having just as much trouble,” says graduate student Alex Coates, who was lead author on the study.

Coates and her colleagues in the Human Performance and Health Research Lab analyzed blood samples from 38 elite runners and triathletes, looking at both iron and hemoglobin levels to determine the prevalence of ID and IDA. They found that 60 per cent of female and 38 per cent of male triathletes had one or more episodes of ID, while the same was true for 56 per cent of female and 31 per cent of male runners. These figures were much higher than what has been previously reported in the literature, say the researchers.

Even more surprisingly, there was a higher incidence of IDA with male elite athletes than their female counterparts (20-25 per cent in males compared to only 0-6.3 percent in females), although there was no clear explanation as to why this was the case.

The higher than expected incidence of iron deficiencies in elite athletes – a group that undergoes frequent and regular monitoring of health and performance – underscores the challenge faced by many of them when it comes to maintaining adequate levels of iron, which is essential to athletic performance.

Low iron levels can be caused by a number of things, such as foot-strike hemolysis (the destruction of red blood cells when a runner’s foot hits the ground), frequent use of nonsteroidal anti-inflammatory drugs, loss through urine and sweat, or nutrient insufficiencies in one’s diet. High levels of a hormone called hepcidin, which increases after a workout, can also reduce iron absorption and tends to counteract the benefits of iron supplementation.

As part of the study, the athletes completed a questionnaire regarding their iron supplementing habits. The researchers found that supplementation was not correlated to an increase in blood iron or hemoglobin levels. The results highlight that there is still work to do to help elite athletes manage their iron levels.

“We need to figure out a better iron supplementation protocol,” says Coates.  She notes that a smaller, more frequent dose of iron, such as a 40-60 mg dose every other day, may allow for better iron absorption compared to a much higher dose taken less often. Additionally, a diet rich in a variety of nutrients and sufficient caloric intake may also help athletes prevent IDA.

Margo Mountjoy from the Health and Performance Centre also contributed to the study.  This work was funded by Athletics Canada and NSERC.

Read the full article in the Clinical Journal of Sport Medicine.

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