What is iron deficiency? how common is it? who is at risk? and how can you measure it? These are the questions we will deal with in this blog and the next blog will discuss the prevention and treatment of iron deficiency.
Iron is an extremely important mineral for athletes, yet iron deficiencies are not uncommon, particularly in endurance athletes. Iron has several roles in the body including the transport and delivery of oxygen, and energy production at the level of the mitochondria. It is also key for both cognitive and immune function. This highlights why iron is critical for performance, and why an iron deficiency could potentially have detrimental impacts. Symptoms indicative of an iron deficiency include tiredness, a lack of energy, shortness of breath, poor recovery and a reduction in performance (especially if experienced when training load is constant, or during a recovery phase).
Athletes are at a greater risk of being iron deficient in comparison to the general population
Why are athletes more likely to be iron deficient?
Athletes are at a greater risk of being iron deficient in comparison to the general population, especially female athletes, with up to ~35% having an iron deficiency versus ~5% in the general population. Regular exercise can increase the likelihood of an iron deficiency. This is because there is an increased inflammatory response in the body post-exercise, which can decrease the body’s ability to absorb iron for 3-6 hours post-exercise. Inflammation increases levels of the hormone hepcidin, which is key for iron regulation. When hepcidin levels increase, iron transport and absorption decreases (1). There is also potentially increased iron loss from exercise due to hemolysis (the destruction of red blood cells), sweating and gastrointestinal bleeding.
There are particular sub-groups of athletes which are more susceptible to suffering from an iron deficiency, including:
Female athletes, in particular those who regularly menstruate because blood losses are higher.
Athletes who follow a plant-based diet. Plant-based foods contain non-heme iron which isn’t absorbed as well by the body in comparison to animal-based foods (which contain heme iron).
Athletes with low energy intake because iron intake is more likely to be insufficient to support the demands of the body.
Adolescent athletes because this time period is associated with increased iron requirements.
Supplementation may be advised to prevent iron stores from declining any further towards Iron deficiency anaemia where performance can be seriously affected.