Iron for Runners

By: Kristi Spence, MS, RDN, CSSD

As a distance runner, there is a lot of talk about iron – what are good sources? Am I getting enough? Is my fatigue related to low iron? etc… Sifting through the anecdotes and finding out what is right for you can be tough, so let’s break it down. Understanding a bit of the science will help you apply some practical tips on how iron can fit into your healthy eating plan.

2007 New York City Marathon – Kristi Spence

What is iron?

Iron is a mineral that we get from various foods and it is essential to a healthy body. While the mineral itself doesn’t give us energy, we get energy from the calorie-containing elements of food (carbohydrate, protein, and fat) – iron, and other vitamins and minerals, allow our bodies to use that energy.

Why is iron important for runners?

Iron is a key component of oxygen transport – getting much-needed oxygen to energy-producing muscles. Without oxygen, our muscles can’t produce much energy, so keeping our iron levels where they should be helps our bodies perform at their optimal levels.  Iron also helps maintain a healthy immune system – very good for athletes.

We lose iron naturally through daily activities like sweating; but distance runners, especially those training at a high level, likely lose even more iron than the average person through increased sweating, increased foot strikes, and minor intestinal bleeding (mostly confined to long, strenuous races).

What happens if iron is low?

If we aren’t getting enough iron, our body’s iron levels become depleted, and iron depletion can progress to iron deficiency and anemia, which are both conditions that limit athletic performance.  For most people, paying attention to getting enough iron from food sources will keep iron levels where they need to be. Testing for depletion involves a blood test.  Supplemental iron is sometimes necessary to maintain adequate levels, but before supplementing, have a blood test and talk with a qualified health care professional to determine the dose that is best for you.

2008 U.S. Olympic Trials – Keeping it fun

So how much do you need, and where can you get it?

Nutrition guidelines recommend 8mg of iron per day for men and 18mg per day for women (women have higher needs due to menstrual losses). Since we don’t eat milligrams, let’s talk about this in terms of food:

Iron exists in two forms:

  1. Heme iron is found in animal products:
    • red meat
    • liver
    • poultry (especially dark meat)
    • fish & other seafood
  2. Non-heme iron is found in plant foods:
    • Fortified cereals
    • Whole grains
    • Legumes – lentils, peas
    • Beans
    • Leafy greens
    • Nuts & seeds
    • Egg yolks (contain both heme and non-heme iron)
    • Sport bars – many are fortified with iron

Heme iron is more readily absorbed than non-heme sources but it is important to incorporate both sources of iron into your diet.

Here are some tips on incorporating iron into your diet:

  • Eat iron rich foods several times per week
  • Enhance iron absorption by consuming non-heme sources with a source of vitamin C – you can do this easily by incorporating fruits and vegetables into your diet with each meal.
  • Eat heme sources of iron (meat) with non-heme sources. This happens pretty naturally – at dinner, we likely eat meat with vegetables or whole grains
  • Cook with a cast iron pot/skillet

Here’s an example of a daily meal plan that delivers ~20mg iron:


  • Oatmeal (made from 3/4cup dried oats)
  • 1 slice whole wheat toast with honey
  • 12 oz fortified orange juice

Snack: Sport Bar


  • Tuna or salmon salad in a whole wheat pita pocket
  • ½ cup cottage cheese
  • ½ cup dried apricots & almonds

Snack: Whole wheat crackers & string cheese


  • Quinoa stir-fry with veggies & protein (beef, chicken, eggs or tofu/tempeh)

Dessert: 1 cup yogurt with berries

Good Eats and Happy Trails!

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