ASK THE SPORTS DIETITIAN Lisa Middleton is a Sports Dietitians Australia member.
Have you ever wondered why Popeye loves to eat so much spinach? The explanation is quite simple, although the iron in spinach is probably more important for running than building muscles. As far as vegetables go, spinach has one of the highest levels of iron (although it may not be in the best absorbable form). Iron is essential for runners, and if you don’t have enough, you won’t be bettering your PB any time soon. Here’s why…
Why is iron important?
Inadequate dietary iron intake can lead to depleted iron stores, or may lead to iron deficiency, anaemia. Iron is an essential component of haemoglobin within red blood cells, which carry oxygen from the lungs around the body. Low iron can lead to low haemoglobin levels, making it difficult to move oxygen to the muscles and brain to support endurance activity.
How do I know if my iron levels are low?
Fatigue is the main symptom associated with low iron levels, and this will significantly affect training and performance. Other symptoms include reduced immune function (recurrent illness), reduced appetite, difficulty concentrating, irritability, pale appearance and impaired tolerance to cold.
Who is at risk?
Regular running can lead to exercise related iron losses. You can lose iron through ‘foot strike’ impact, which can damage red blood cells. Iron can be lost through sweat and can also be lost via the gastrointestinal tract. Heavy training will increase the production of red blood cells, and therefore the need for iron.
If you are female, adolescent, vegetarian, on a diet, or have a very high carbohydrate intake you may also be at risk of low iron levels. If you are vegetarian or don’t eat enough protein-rich foods, and you run, you may not be consuming enough iron to meet your needs.
How do I get enough iron?
Red meat contains by far the most iron in terms of the total amount absorbed. Haem iron is found in animal meat sources, such as meat, seafood and chicken, and absorption is significantly greater compared to non-haem iron found in plant sources. Including a small amount of lean red meat around 2-3 times per week is a great step towards increasing iron intake (sneaking in some liver and oysters will help too)! Vegetarians need to carefully plan their nutrition intake to maximise iron absorption. Adding vitamin C to non-haem iron sources can significantly enhance absorption. Foods such as strawberries, kiwi-fruit, citrus, broccoli, cauliflower or red capsicum to non-haem iron sources like, green leafy vegetables, legumes, quinoa, wholegrains, eggs, nuts/seeds and breakfast cereals. Avoid drinking tea with meals too.
Don’t take an iron supplement just because you are feeling tired, as a range of factors can contribute to fatigue. There is also a risk of consuming too much iron and impairing absorption of other minerals such as zinc. If you suspect low iron, organise with your GP to have a blood test. If your iron levels are low, see an Accredited Sports Dietitian to ensure you are maximising dietary iron intake and absorption and to determine whether a supplement is required.
So just like Popeye, keep your iron levels up to train and perform at your best.
For more information check out the fact sheet on Sports Dietitians Australia website, ‘Iron Depletion in Athletes’.