Iron Deficiency in the Female Athlete - an updated perspective

By Lynsey Martin.

Being a female athlete presents unique challenges in maintaining healthy iron stores. Anyone who participates in activities such as running or other high-impact sports faces the risk of hemolysis (the rupture of red blood cells) due to mechanical factors like foot impact, muscle contraction, and vasoconstriction, as well as metabolic factors in response to exercise, including dehydration, oxidative damage, and proteolysis [1]. Interestingly, a large cross-sectional study found that female athletes involved in sports requiring a mix of aerobic and anaerobic energy systems are at the highest risk for iron deficiency [2]. Additionally, one of the main challenges faced by most reproductive-aged women is the increase in blood loss during menstruation. Factors such as following a plant-based diet or living at a higher altitude can further contribute to the risk of deficiency.

Another challenge women face is defining what constitutes iron deficiency. The Hemochromatosis and Iron Overload Screening Study (HEIRs) defines it as a combined transferrin saturation of less than 10% and serum ferritin of less than 15 ng/mL. The World Health Organization (WHO) defines it as a serum ferritin level of less than 15 ng/mL, while the widely accepted threshold for iron-deficient erythropoiesis (IDE) is a serum ferritin level of less than 25 ng/mL [3]. In Canada, if your serum ferritin level is above 20 ng/mL (sometimes even 10 ng/mL), doctors typically do not flag your bloodwork for a deficiency, even if you present with hallmark symptoms like fatigue, trouble concentrating, anxiety, or issues related to endurance or high-impact sports, with compounding factors like a heavy menstrual cycle.

Recently, Ontario updated its guidelines, setting the lower limit for ferritin at 30 ng/mL. This change, which was four years in the making, will likely help more people identify and address their iron deficiency before it progresses to anemia and, in general, may help them feel better [4]. While this is a step in the right direction for the general public, it may not be enough for athletes to perform at their best.

Although the optimal serum ferritin level for athletes hasn’t been officially established, in discussions with a doctor who has worked with elite athletes and recreationally active women, achieving a ferritin level of around 100 ng/mL has been shown in clinical practice to improve performance and overall energy levels.

It is important to note that excessively high ferritin levels also carry risks. A serum ferritin level higher than 200 ng/mL in women and 300 ng/mL in men can cause harm at the intestinal, vascular, and cellular levels due to increased oxidative damage and a higher risk of myocardial infarction [5]. For this reason, athletes should not take iron supplements "just in case." They should have bloodwork done regularly to assess their need for supplementation. What all of this highlights is the importance of athletes—whether recreational or elite—advocating for themselves, understanding the difference between sufficient and optimal iron levels, and seeking doctors who also recognize this distinction.

From a dietary perspective, there are ways to maximize iron absorption, which can be addressed even without bloodwork, as it is generally difficult to reach iron overload without taking supplements. First, as mentioned earlier, athletes who are willing to include meat in their diet can benefit from excellent sources of heme iron, such as beef, oysters, venison, and mussels. Heme iron is more bioavailable, meaning it is absorbed and utilized by the body more efficiently. For those following a plant-based diet, sources like spinach, dried apricots, and pumpkin seeds are also great options. While these provide non-heme iron, which is less readily absorbed, they can still significantly contribute to improving iron status.

References:

1.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6614330/
2. https://pubmed.ncbi.nlm.nih.gov/20882295/
3.  https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2819707#:~:text=Prevalence%20rates%20of%20iron%20deficiency%20among%202039%20women%20aged%2025,736%20women)%20according%20to%20IDE.
4.  https://www.cbc.ca/news/canada/toronto/iron-deficiency-bloodwork-testing-ontario-1.7314795
5. https://www.researchgate.net/publication/41669607_Iron_excess_in_recreational_marathon_runners/link/02e7e527515cc736c3000000/download?_tp=eyJjb250ZXh0Ijp7ImZpcnN0UGFnZSI6InB1YmxpY2F0aW9uIiwicGFnZSI6InB1YmxpY2F0aW9uIn19

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