Why Do Female Athletes So Often Lack Iron?
Iron deficiency is the most common nutritional deficiency in the world, and exercising women are the highest-risk group. According to research data, 30–60% of female athletes have iron deficiency or anemia, compared with 10–15% in the general population.
🩸 Menstruation
Every month, 30–40 ml of blood is lost, which corresponds to 15–20 mg of iron per cycle. Heavy periods can double the losses.
👟 Foot strike
Running and other impact sports cause erythrocyte hemolysis (breakdown of red blood cells) due to mechanical impact on the feet. This is called “runner’s anemia”.
💧 Sweating
About 0.3–0.5 mg of iron is lost with sweat per liter of sweat. During intense training, this can amount to a significant amount.
🥩 Dietary Restrictions
Female athletes often restrict calories and/or red meat, and in plant-based diets iron absorption is 2–3 times lower.
🔬 Stages of Iron Deficiency
| Stage | Ferritin (µg/L) | Hemoglobin | Symptoms | Solution |
|---|---|---|---|---|
| 1. Iron Depletion | < 35 | 35 µg/L is already considered a functional deficiency, even if hemoglobin is normal. Optimal for female athletes — 50–100 µg/L.120 g/L) | May be no symptoms or mild fatigue | Change diet + low-dose supplements |
| 2. Iron Deficiency Without Anemia | < 20 | Within normal range | Fatigue, reduced endurance, poorer recovery | Iron supplements for 2–3 months |
| 3. Iron Deficiency Anemia | < 12 | Low (< 120 g/L) | Severe fatigue, shortness of breath, pallor, cold extremities, dizziness | Physician supervision, higher doses |
⚠️ Important: Ferritin level for female athletes < 35 µg/L is already considered a functional deficiency, even if hemoglobin is normal. Optimal for female athletes — 50–100 µg/L.
🚨 Iron Deficiency Symptoms in Female Athletes
- Persistent fatigue: You feel tired even after a full night’s sleep. This is the most common symptom.
- Reduced performance: You cannot reach your usual training intensity; strength and endurance drop.
- Shortness of breath: Shortness of breath even with a light load that previously felt easy.
- Rapid heartbeat: The heart beats faster than usual at rest and during physical exertion.
🔴 Other symptoms: Pale skin, brittle nails, hair loss, cold hands and feet, dizziness upon standing, reduced concentration, irritability, restless legs syndrome, craving to eat ice or chalk (pica).
💊 Forms of Iron Supplements
| Form | Elemental iron | Absorption | Side Effects | Recommendation |
|---|---|---|---|---|
| Iron bisglycinate (chelated) | ~20% | High (2–4× better) | Minimal | Best Choice |
| Iron fumarate | ~33% | Good | Intermediate | Good, cheaper |
| Iron sulfate | ~20% | Good | Highest | Cheaper, more side effects |
| Iron gluconate | ~12% | Intermediate | Intermediate | Suitable for more sensitive individuals |
| Heme iron (from animals) | — | Best (15–35%) | Minimal | Excellent, More Expensive |
🎯 How to Take Iron Correctly
Golden rules for iron intake:
- Take with vitamin C: 200–500 mg of vitamin C together with iron increases absorption 2–3 times. An excellent choice: orange juice.
- Avoid coffee and tea: Tannins in coffee and tea block iron absorption. Do not drink coffee/tea 1–2 hours before and after taking iron.
- Do Not Take with Calcium: Calcium competes with iron. Dairy products, calcium supplements — at least 2 hours apart.
- On an Empty Stomach: Iron is best absorbed on an empty stomach. If it causes nausea — take it with a light meal, but not with milk.
- Every Other Day: Taking iron every other day (instead of daily) is thought to produce almost the same effect with fewer side effects. The hormone hepcidin blocks absorption for 24–48 h after a dose.
✅ Dosing Example: Iron bisglycinate 25–50 mg of elemental iron every other day, in the morning on an empty stomach, with 500 mg of vitamin C. After 2–3 months, check your ferritin.
🥩 Heme vs Non-Heme Iron
| Property | Heme Iron | Non-Heme Iron |
|---|---|---|
| Source | Animal sources (meat, fish, poultry) | Plant-based (spinach, lentils, beans) |
| Absorption | 15–35% | 2–13% |
| Absorption Inhibitors | Almost no effect | Strongly affected by tannins, calcium, phytates |
| Absorption Enhancers | Meat itself improves | Vitamin C, meat, fish (the “meat factor”) |