Iron insufficiency in runners, especially female runners, is very common. Low levels of iron in the blood can contribute to tiredness, impact adrenal and thyroid hormone health, and result in poor training and race performance. The good news is that there is plenty that can be done through the food we eat.
Often, health conscious female runners have questions around food sources of iron, assuming that iron insufficiency and associated low energy can only be resolved by eating a juicy steak every day. Definitely not so. True that the most bio-available and absorbable form of iron is haem iron from animal sources such as lean red meat, oily fish, dark meat of poultry, and eggs. However, plant food sources of iron, including beans and pulses, dark green leafy vegetables, and dried fruit provide good amounts of iron and are reasonably bio-available so can absolutely contribute to iron intake. Don't forget that iron is better absorbed when eaten with foods rich in vitamin C, such as fruit and lightly cooked or raw vegetables.
Symptoms of Iron Insufficiency
It is not the easiest process for runners to determine if they are iron deficient. Fatigue, and sometimes a slight shortness of breath, are the most common symptoms of iron insufficiency. But how do you know if this is normal tiredness feeling out of breath from a run, or something more?
Keeping a log of how you feel before, during and after each run can be a first step. If you notice any patterns or changes in energy levels then consider getting your iron levels checked. A simple blood test from your GP is a good first step. Most commonly the GP will measure ferritin level, which is a measure of how much iron is stored in your body. Just be aware that optimum ferritin levels are different for a GP than for running performance. For example, 8.0 ng/mL is classed as 'normal' by a GP, but is insufficient for optimum health and running performance.
Runners and Iron Loss
We all use up iron stores on a daily basis but runners, especially female endurance runners, typically deplete quicker than average.
Sweating promotes iron loss. Not always in huge amounts, but if running in hot and humid conditions the sweat loss can contribute to significant iron loss. Some runners experience small losses of iron through the stomach and large intestine, the GI tract, which again can contribute to significant iron losses over time. And for female runners, we have menstruation to contend with, where the monthly loss of blood reduces iron stores significantly. It is therefore vital to consume an iron-rich diet in order to keep iron levels in the body high enough for good health and running performance.
What to eat
As well as the foods discussed above, here are my top four plant sources of iron. They are all healthy, nutritious foods that are rich in iron and are generally well absorbed:
Lentils - tinned are a useful store cupboard basic
Dried apricots - aim for untreated apricots which will be darker in colour
Spinach - lightly cooked for maximum iron absorption
Pumpkin seeds - a small handful on salads, soups or porridge
If you need personalised advice on iron insufficiency and which foods are best for you to eat
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Helen Morton, runner and food lover, sharing latest nutrition research and recipes.