This gracious post was created and shared by Erin Wos, DO, MS, a Sports Medicine Physician at the Vancouver Clinic in Vancouver, Washington. Erin is a speaker and contributor for Whisper Running. Her roots date back to her days as a successful high school, collegiate, and professional track and field athlete. Erin is still involved with track and field through USATF, serving as the team physician for the 2025 NACAC Championships. To schedule an appointment with Erin, visit the TVC page.
Why Iron Matters for Youth Distance Runners
Iron is a mineral that helps your body move and use oxygen—and if you’re a runner, that’s a big deal. Iron helps build hemoglobin and myoglobin, two important proteins that carry and store oxygen in your blood and muscles. It also helps make enzymes your body uses to create energy during exercise.
When you don’t have enough iron, your muscles don’t get the oxygen they need to perform well. This can lead to iron-deficiency anemia, a condition that can cause fatigue, leg cramps, pale skin, dizziness, or a big drop in your running performance. Even without full-blown anemia, low iron levels can still make workouts harder and recovery slower. You might feel like you're working harder than usual, but running slower than before [1,2].
Distance runners—especially teenagers—are more likely to have low iron because of how much their bodies go through during training. Long runs and hard workouts can lead to iron loss through sweat, urine, tiny amounts of bleeding in the gut, and even something called foot-strike hemolysis—where red blood cells break down from the repeated pounding on hard surfaces. Female runners also lose iron through their periods. Runners who don’t eat much meat, who follow vegetarian diets, or who don’t eat enough in general are also at higher risk [1,2].
That’s why major sports and nutrition organizations recommend regular iron checks for endurance athletes. In fact, women, vegetarians, and regular blood donors may need more than the usual daily amount (18 mg for women and 8 mg for men) to stay healthy and strong [2].
Food First: Iron-Rich Foods to Fuel Your Body
The best way to support your iron levels is through your diet. There are two main kinds of iron in food:
Heme iron comes from animal products and is the easiest for your body to absorb.
Non-heme iron comes from plant foods and is still useful, but your body has to work a little harder to absorb it.
Here are some examples of heme iron foods:
Beef and red meat
Chicken (especially thighs, drumsticks, and liver)
Turkey
Pork
Fish (like tuna or salmon)
Eggs
And here are great non-heme iron options:
Spinach, kale, and other leafy greens
Lentils, beans, and chickpeas
Tofu and tempeh
Iron-fortified cereals and breads
Quinoa
Nuts and seeds (like pumpkin seeds or cashews)
Dried fruit (apricots, raisins)
To help your body absorb non-heme iron, pair it with vitamin C-rich foods, like oranges, strawberries, bell peppers, or a splash of lemon juice on greens. Try to include a few servings of both heme and non-heme sources each week, especially on heavy training days.
When Food Isn’t Enough: How to Use Iron Supplements Safely
Sometimes, even if you’re eating well, your body may still fall short—especially if you’re training hard or growing quickly. In these cases, a healthcare provider may suggest an iron supplement. But it’s important not to take supplements without getting tested first. Too much iron can cause its own problems and might be dangerous if it’s not needed [1,2].
If a doctor or dietitian recommends a supplement, look for one of these types, which are absorbed best:
Ferrous sulfate
Ferrous fumarate
Ferrous bisglycinate (this one is often gentler on the stomach)
Top-rated brands from Consumer Labs (third-party testing site that independently tests health and wellness products/supplements for correct identification, dosing, purity, and dissolvability):
Because iron supplements can cause side effects like constipation or stomach pain, it’s smart to start slowly—try taking it every other or every third day. Also, pay attention to the dosage of the supplement that is used. Higher doses of iron (45mg) will not require daily dosing. It also helps to:
Take iron with a vitamin C source (like orange juice or a small supplement)
Avoid taking iron at the same time as calcium (like milk, cheese, or supplements containing calcium), which blocks absorption
Take it on an empty stomach if possible, but if that causes discomfort, a light snack without dairy is okay
Refilling low iron stores can take 3 to 6 months, so catching it early or preventing it altogether is the best strategy. Long-term deficiency—even without anemia—can hurt both your health and your performance [1].
Bottom line: Iron is one of the most important micronutrients for youth distance runners. It fuels your muscles, boosts your endurance, and keeps your energy up. If you’re feeling more tired than usual, struggling in workouts, or just not feeling like yourself, talk to a sports medicine doctor about checking your iron levels. Keeping your iron stores healthy is one of the best things you can do to support your running and your overall health.
References
Peeling, P., et al. (2009). Iron status and the acute post-exercise hepcidin response in athletes. European Journal of Applied Physiology. https://pubmed.ncbi.nlm.nih.gov/19225360/
Thomas, D.T., Erdman, K.A., & Burke, L.M. (2016). Nutrition and Athletic Performance: Joint Position Statement. Medicine & Science in Sports & Exercise. https://journals.lww.com/acsm-msse/fulltext/2016/03000/nutrition_and_athletic_performance.25.aspx
https://www.consumerlab.com/reviews/iron-supplements-review/iron/?search=Iron
Erin Wos, DO, MS
Sports Medicine Physician
Vancouver Clinic
https://www.tvc.org/clinician/erin-wos-do/