Iron is one of the most overlooked nutrients in performance nutrition, yet it plays a central role in energy, endurance and recovery. Whether you're a competitive endurance athlete or training consistently for the first time, understanding your iron status could be the difference between progressing and plateauing.
Here’s what you need to know:
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IRON POWERS YOUR OXYGEN DELIVERY SYSTEM
Iron is essential for haemoglobin, the protein in red blood cells that carries oxygen from your lungs to your muscles. Without enough iron, oxygen delivery declines, endurance suffers and fatigue sets in faster. For athletes, this directly impacts performance capacity and training quality.
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SUPPORTS ENERGY PRODUCTION
Iron is involved in energy metabolism at the cellular level. Low iron can leave you feeling flat, sluggish and unable to hit your usual training intensities. If your workouts feel harder than they should, iron status may be worth checking with your doctor.
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ATHLETES MAY NEED SIGNIFICANTLY MORE IRON
Research suggests endurance athletes, particularly female endurance runners, may require considerably more iron than the general population. Athletes experience greater iron losses due to sweat, increased red blood cell turnover, mechanical stress (such as foot strike in running), acute inflammation from training and altitude exposure. Higher training loads generally mean higher iron demands.
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WOMEN AND MENSTRUATING ATHLETES ARE AT GREATER RISK
Menstruating athletes have particularly high iron requirements due to regular blood loss. Combined with the demands of endurance training, this creates conditions that can lead to deficiency if intake isn't adequate.
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FOOD ALONE MAY NOT ALWAYS BE ENOUGH
Iron-rich food sources include: Haem sources (more readily absorbed): oysters, beef, lamb, sardines. Non-haem sources (plant-based): lentils, tofu, edamame, pumpkin seeds, fortified cereals.
Plant-based iron is less efficiently absorbed. Those eating a plant-forward diet may need to consume more iron overall to meet the same needs. For some athletes, particularly those with higher demands, food alone may not be sufficient.
A MORE EFFECTIVE APPROACH TO IRON
When iron supplementation is necessary, quality and formulation matter. Choosing highly bioavailable forms such as iron bisglycinate with vitamin C to support absorption can help maximise effectiveness while remaining gentle on the gut. For competitive athletes, it’s also important to select products that are certified and batch tested.
Most importantly, iron supplementation should always be guided by blood test results and the advice of a qualified health professional to ensure the right dose at the right time for your individual needs.
Iron and Performance: The Hidden Limiter In Athletes