"Your hemoglobin is fine" - but you're still exhausted. Sound familiar? Iron deficiency without anemia (IDNA) affects millions of women yet can go undiagnosed because doctors may focus on hemoglobin alone.
Understanding Iron Deficiency
Iron deficiency can progress in stages: 1. Depleted iron stores: Ferritin can drop, but hemoglobin may be normal 2. Iron-deficient erythropoiesis: Iron supply can't meet red blood cell needs 3. Iron deficiency anemia: Hemoglobin can finally drop
By the time you're anemic, you may have been iron deficient for a long time.
Why Ferritin Matters
Ferritin is your iron storage protein. It can drop long before hemoglobin does. Some research has found that ferritin below 50 ng/mL can cause fatigue symptoms, even when hemoglobin is perfectly normal.
Symptoms Low Ferritin May Cause
- Fatigue and weakness
- Hair loss
- Restless leg syndrome
- Difficulty concentrating
- Shortness of breath with exercise
- Cold hands and feet
- Brittle nails
Optimal Ferritin Levels
Labs may list 12-150 ng/mL as normal. But optimal for energy may be:
- Minimum: 50 ng/mL
- Optimal: 70-100 ng/mL
- For hair loss: >70 ng/mL
The Complete Iron Panel
Don't just test ferritin. A complete picture includes:
- Ferritin
- Serum Iron
- TIBC (Total Iron Binding Capacity)
- Transferrin Saturation
References
- Camaschella, C. (2015). Iron-deficiency anemia. New England Journal of Medicine, 372(19), 1832-1843. PMID 25946282
- Vaucher, P., et al. (2012). Effect of iron supplementation on fatigue in nonanemic menstruating women with low ferritin: a randomized controlled trial. Canadian Medical Association Journal, 184(11), 1247-1254. PMID 22777991
- Lopez, A., et al. (2016). Iron deficiency anaemia. Lancet, 387(10021), 907-916. PMID 26314490
