Written by Justyna Wiraszka
Reading Time: 6 Minutes

You exercise regularly and spend multiple hours a week engaging in sport activities. You watch what you eat, you limit sweets, snacks and alcohol intake. And yet, you still feel fatigue. Sounds familiar? If it does, one possible reason could be low iron levels. And while there are numerous articles online on iron deficiency, there is very little relevant information out there that addresses athletes and sportspeople in particular.

Iron plays an important physiological role. It is responsible for transporting oxygen and producing energy in the body. Unfortunately, despite their healthy and active lifestyle, athletes and sportspeople are often faced with iron deficiency. In fact, The International Olympic Committee 2009 Consensus  recommends regular screening for iron deficiency in athletes. For sportspeople, this is especially important since iron deficiency can lead to diminished endurance capacity and can thus limit achievements during training.

There are several mechanisms which have been suggested to be associated with an increased risk of iron depletion during exercise. But before we dive into the actual cause of iron deficiency in athletes, let’s establish some facts. We will start with what ferritin is and why it is important. We will walk you through the role of iron, what symptoms you might experience while being iron deficient and how to mitigate iron deficiency as a sportsperson. Shall we?

What is ferritin and why is it important?

Ferritin is a protein that supports storing iron in your body. Imagine ferritin as a sphere in which iron is kept. Ferritin is mostly found in the liver, spleen, bone marrow, and skeletal muscle, and to a small extent in blood. The small amount of ferritin that circulates in the blood reflects the body’s total iron stores. This means that testing ferritin allows you to assess how much iron is stored in your body.

We have now established what ferritin is, but what about iron?

What is iron?

Iron is found in your red blood cells, where it is attached to hemoglobin. Together with hemoglobin, iron transports oxygen in the blood from the lungs to other tissues. Now, iron is also involved in red blood cell production and is required for a proper immune function.

What is important to remember is: Ferritin stores iron, and iron transports oxygen.

What are the symptoms of iron deficiency?

There can be a variety of symptoms related to iron deficiency. Common symptoms include pale skin, tiredness, cold hands and feet, dizziness, headaches and poor physical performance. However, iron deficiency can sometimes be “silent”, i.e. it can occur in the absence of visible symptoms. That is why it is crucial to regularly test for iron levels.

We have now introduced to you the concept of ferritin, iron and iron deficiency symptoms. Let’s now go into detail about the connection between sport and iron deficiency. 

Why are people who exercise regularly at risk of iron deficiency? 

When we talk about risk of iron deficiency, we normally refer to ferritin levels lower than 30 ng/ml. Our Bloom App also uses this cut-off and marks everything below 30 ng/ml as “low ferritin level”, as you can see below.

It is a well known fact that athletes and sportspeople are at a higher risk of iron deficiency as compared to the general population, or those with a sedentary lifestyle. There are multiple hypotheses of why athletes are at a greater risk of iron depletion but scientists still have to agree on the factor with the greatest impact.

The first explanation is that, over a period of time, sport increases your overall iron need while simultaneously more iron is lost during heavy training, e.g. through sweating. If the levels of iron are not compensated by iron supplementation or an iron-rich diet, it will result in low ferritin levels overtime.

Another possible cause, supported by other researchers, is that red blood cells break down faster in sportspeople, depending on the form of exercise. In particular, the mechanical force called footstrike, which is how you land on your feet during walking or running, has been associated with hemolysis (= the destruction of red blood cells).

The third theory finds hepcidin bursts to be the culprit as it is known to regulate iron metabolism. Since hepcidin is known to reduce or block iron absorption, it can have an impact on iron stores during and after exercise. Several studies have shown that the blood levels of hepcidin increase during days of intense exercise, which then negatively impacts iron stores.

As you can see, there are various hypotheses of why iron deficiency can occur in athletes. With all these possible causes, only regular check-ups can give proper insights into sportspeoples’ health.

But, even if your iron levels turn out to be low, there are a few things you can do in order to keep them in balance. Read on to learn more.

How to mitigate iron deficiency as an athlete?

One way to replenish iron levels is via your diet. For this it is good to know that heme iron, mostly present in meat and seafood, is easily absorbed. Plants, such as beans, nuts and certain legumes mostly contain non-heme iron which has lower bioavailability and is thus less well absorbed.

When planning iron-rich meals, it also helps to remember certain substances which improve or disrupt iron absorption. For example, adding foods rich in vitamin C (e.g. fruits), can help improve the absorption of iron by the body. Milk products, coffee and tea have the opposite effect and inhibit iron absorption. If the goal is to increase the body’s iron stores, these foods should therefore not be consumed together with iron-rich foods.

Recommendations on the exact amount of daily iron intake vary between different sources. According to the National Health Service (NHS) England, men over 18 years old need 8.7 mg a day, while women aged 18 to 50 need around 14.8 mg a day. The Institute of Medicine (USA) recommends 8 mg for men and postmenopausal women and 18 mg for premenopausal women.

If you want to take one step further towards having a well-balanced meal, it is recommended that you speak to a dietician. Additionally, you can talk to your doctor about specific supplements. However, before taking any further action, the first step should always be to check your current iron store levels.

How can ferritin be checked?

Measuring serum ferritin as an indicator for the body’s iron store is widely established in clinical practice. Low ferritin levels indicate iron deficiency whereas elevated ferritin levels may point out a possible iron overload.

The Bloom Ferritin Test checks if your ferritin is within the normal range or at a low or high level. The result is available on your smartphone within a few minutes, including a personalized interpretation of the value and, if needed, recommendations on how to improve your iron store levels.

Would you like to know more about the Bloom Ferritin Test? Read more about it here. 

References

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2. Anthl T. The International Olympic Committee (IOC) Consensus Statement on Periodic Health Evaluation of Elite Athletes: March 2009. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2742466/.
   Published 2009, Access March 29, 2022. 
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4. Sumi D, Hayashi N, Yamaguchi K, Badenhorst CE, Goto K. Hepcidin response to three consecutive days of endurance training in hypoxia. Eur J Appl Physiol. 2021;121(4):1197-1205. doi:10.1007/s00421-021-04599-3 Published February, 2021. Accessed March 29, 2022.
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7. Córdova A, Mielgo-Ayuso J, Fernandez-Lazaro CI, Caballero-García A, Roche E, Fernández-Lázaro D. Effect of Iron Supplementation on the Modulation of Iron Metabolism, Muscle Damage Biomarkers and Cortisol in Professional Cyclists. Nutrients. 2019;11(3):E500. 10.3390/nu11030500 Published february, 2019. Accessed March 29, 2022.
8. Centers for Disease Control. Second National Report on Biochemical Indicators of Diet and Nutrition in the U.S. Population. Atlanta (GA); 2012. https://www.cdc.gov/nutritionreport/pdf/Nutrition_Book_complete508_final.pdf. Accessed August 2, 2019.