Key takeaways
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A 2019 narrative review (Sim et al.) reported iron deficiency in about 15-35% of female athlete cohorts and about 5-11% of male athlete cohorts. The NHS says that heavy periods and pregnancy are very common causes of iron deficiency anaemia. The EU-authorised wording for iron, as listed in the EU Register, is shown below.
The NHS says that most people should be able to get all the iron they need by eating a varied and balanced diet, and that anyone taking iron supplements should not take too much, as this could be harmful.
Why athletes lose more iron than other people
A 2021 narrative review (Damian et al.) lists the ways iron is lost during exercise as sweating, hematuria, gastrointestinal bleeding, inflammation, and intravascular and extravascular hemolysis, and describes intravascular hemolysis during running as occurring because of the footstrike. The Sim et al. review highlighted exercise-induced increases in the iron-regulatory hormone hepcidin as a contributing factor towards altered iron metabolism in athletes.
Why menstruating women face extra risk
The NHS says that women who lose a lot of blood during their monthly period (heavy periods) are at higher risk of iron deficiency anaemia and may need to take iron supplements, and it advises speaking to a GP or a registered dietitian for more advice.
What the EU-authorised iron claims cover
The NHS says that iron is important in making red blood cells, which carry oxygen around the body, and that a lack of iron can lead to iron deficiency anaemia. The exact EU-authorised wording for iron is shown in the box at the top of this page.
Symptoms the NHS lists for iron deficiency anaemia
- Tiredness and lack of energy
- Shortness of breath
- Noticeable heartbeats (heart palpitations)
- Paler than usual skin, and headaches
These symptoms are not specific to iron. The NHS says that a GP will usually do a blood test (a full blood count) to find out if the number of red blood cells is normal.
Food sources versus supplements
The NHS lists liver (but not during pregnancy), red meat, beans such as red kidney beans, edamame beans and chickpeas, nuts, dried fruit such as dried apricots, fortified breakfast cereals and soy bean flour as good sources of iron. The EU-authorised wording for vitamin C is shown below.
The NHS says that drinking orange juice after taking an iron tablet may help the body absorb the iron, and that iron tablets are recommended once a blood test shows a low red blood cell count.
When and how to get tested
The NHS advises seeing a GP if you think you might have iron deficiency anaemia; the GP will usually do a full blood count blood test. A doctor or sports dietitian can interpret results and decide whether supplementation is warranted.
The risk of over-supplementing
The NHS says that side effects of taking high doses (over 20mg) of iron include constipation, feeling sick, being sick and stomach pain, and that very high doses of iron can be fatal, particularly if taken by children, so iron supplements should be kept out of the reach of children. It also says that taking 17mg or less a day of iron supplements is unlikely to cause any harm.
Putting it together
This guide has set out what the NHS and two narrative reviews say about iron in athletes, the symptoms the NHS lists for iron deficiency anaemia, and the EU-authorised wording for iron and vitamin C shown in the boxes. Our guides on vitamin D and magnesium cover those nutrients. Local Malta and Cyprus retailers stock iron and other core nutrition products; ask a GP or dietitian before taking iron supplements.
Source: Sim et al. 2019 – Iron considerations for the athlete: a narrative review (PubMed), Damian et al. 2021 – Anemia in Sports: A Narrative Review (PMC), EU Register of nutrition and health claims, NHS – Iron, NHS – Iron deficiency anaemia.
Frequently asked questions
Why are athletes more likely to have low iron?
A 2021 narrative review (Damian et al.) lists the ways iron is lost during exercise as sweating, hematuria, gastrointestinal bleeding, inflammation, and intravascular and extravascular hemolysis. A 2019 narrative review (Sim et al.) highlighted exercise-induced increases in the hormone hepcidin as a contributing factor towards altered iron metabolism in athletes.
Why are female athletes at higher risk of iron deficiency?
The NHS says that women who lose a lot of blood during their monthly period (heavy periods) are at higher risk of iron deficiency anaemia. A 2019 narrative review (Sim et al.) reported iron deficiency in about 15-35% of female athlete cohorts and about 5-11% of male athlete cohorts.
What are the EU-authorised claims for iron?
The exact EU-authorised wording for iron is shown in the box on this page. The NHS says that iron is important in making red blood cells, which carry oxygen around the body.
Should athletes take an iron supplement without testing first?
The NHS says that most people should be able to get all the iron they need by eating a varied and balanced diet, and that iron tablets are recommended once a blood test shows a low red blood cell count. It lists side effects of high doses (over 20mg) as constipation, feeling sick, being sick and stomach pain.
When should an athlete get tested for low iron?
The NHS advises seeing a GP if you think you might have iron deficiency anaemia; the GP will usually do a full blood count blood test.