Runners and iron: Let’s stop supplementing and start screening

Here is a message all runners need: you cannot iron supplement your way out of an energy deficit. 

A recent study¹ that aimed to assess risk for the Female Athlete Triad in high school distance runners found that while 42% of the study participants were supplementing with iron, it made no difference in who developed Triad symptoms or not. Those who supplemented with iron and those who didn’t had the same Triad risk. The Triad is a model of three related components of female athlete health: energy availability, menstrual health, and bone health. Energy status drives menstrual health and bone health. Being in an energy deficient state interferes with having consistent periods, which leaves bones less protected due to lack of monthly hormonal fluctuations. This spells trouble for the young female runner whose bones need to withstand the stress of running and daily activities.

More runners have asked me if they should be supplementing with iron than I can count. Iron has long-been the “it” fix in the running community, dating back to when I was in college. As a team, we regularly had our iron levels checked. If found to be low, we were given iron tablets to take. If really low, we were given liquid iron. Then, well, nothing. That was the extent of treating low iron. Hopefully you felt better and ran better.

While iron plays an important role of oxygen transport in the body, I’ve observed runners using their iron status as the root of all health and performance issues. Iron seems to be an easy go-to culprit to rationalize decreased performance, lasting fatigue, and menstrual dysfunction. Too often, I’ve heard runners, parents, and coaches discuss the virtues of iron and the importance of iron supplementation. 

But what if iron isn’t the holy grail for running health and performance? 

Instead of blaming low iron as the cause of running health and performance distress, we need to look deeper into the complex system that makes up a runner. 

Hemotological health, or the make-up of blood, is one component of a runner’s multi-dimensional ecosystem that includes cardiovascular, bone, menstrual, psychological and endocrine health, to name a few. Iron status is one cog in a complex system. Runners need to be aware when the system is failing, not just a single component in isolation.

Scapegoating iron doesn’t address the effects of low energy availability, which is at the heart of Relative Energy Deficiency in Sport (RED-S) and the Female and Male Athlete Triad.

RED-S highlights that many body systems are affected by low energy availability. Addressing this disorder includes having health care providers assess nutritional status, training habits, and beliefs about health and performance. If a runner is given the tools to address their energy deficit, an iron deficiency may in turn be addressed via healthier fueling and training strategies. No amount of iron supplementation will provide a sufficient energy source to address a fueling deficit or training overload. 

The largest survey of adolescent female athletes identified that those with low energy availability were at greater odds to suffer health and performance consequences of RED-S compared with young women with adequate energy intake.² This survey of 1000 girls ages 15-30 found that athletes with low EA are 1.6x more likely to report a history of hematological issues like anemia, low hemoglobin, low iron or ferritin, or abnormal bruising. What this highlights is that RED-S could be driving a runner’s low iron status, so addressing iron levels without addressing an underlying energy deficit will never be enough. 

Why are we focused on a runner’s iron status instead of screening and monitoring for low energy availability? The study points out that Triad screening is uncommon in high school athletes. This needs to change. If a runner is screened and educated about low energy availability in early adolescence, RED-S, the Triad, and an iron deficiency may never have a chance to flourish. 

Iron alone is not the root of most health and performance issues. As a running culture, we need to stop placing as much importance on iron supplementation (especially without physician monitoring) and start screening for the Triad and RED-S.

1. Skorseth P, Segovia N, Hastings K, Kraus E. Prevalence of Female Athlete Triad Risk Factors and Iron Supplementation Among High School Distance Runners: Results From a Triad Risk Screening Tool. Orthop J Sports Med. 2020;8(10):232596712095972. doi:10.1177/2325967120959725

2. Ackerman K, Holtzman B, Cooper K et al. Low energy availability surrogates correlate with health and performance consequences of Relative Energy Deficiency in Sport. Br J Sports Med. 2018;53(10):628-633. doi:10.1136/bjsports-2017-098958

Katie Noble is a Doctor of Physical Therapy, a journalist, and a runner. She enjoys empowering and supporting female runners with evidenced-based education.