From the Guidelines
Iron deficiency without anemia is primarily caused by insufficient dietary iron intake, increased iron requirements, blood loss, and malabsorption issues, as evidenced by recent studies 1. The condition, often called latent iron deficiency or iron deficiency without anemia (IDWA), can develop due to several reasons. Common causes include:
- Insufficient dietary iron intake, especially in vegetarians and vegans who consume limited animal-based iron sources
- Increased iron requirements during periods of rapid growth, such as in adolescent athletes, as noted in the study 1
- Blood loss from heavy menstrual periods, gastrointestinal bleeding, or frequent blood donations, which can deplete iron stores before affecting hemoglobin levels
- Malabsorption issues due to celiac disease, inflammatory bowel disease, or gastric bypass surgery, which can prevent proper iron absorption According to the study 1, iron deficiency, even without anemia, can have negative implications for aerobic performance, and postpubertal female players are at the highest risk of iron deficiency due to regular blood loss during menstrual bleeding and possibly due to a diet less rich in meat. The study also suggests that a reasonable time frame for assessment of iron status is once per year in male players and twice per year in female players, and that iron deficiencies may present as lethargy and reduced performance, and can be identified through blood screening 1. Diagnosis typically involves measuring serum ferritin, transferrin saturation, and other iron markers while hemoglobin remains in the normal range, as defined in the study 1, which states that iron deficiency is defined as low serum ferritin (<35 μg/L) and normal blood haemoglobin values. Treatment usually includes oral iron supplements, such as those rich in haem iron, including meat and seafood, and non-haem iron sources with co-ingested vitamin C to enhance absorption, as recommended in the study 1.
From the Research
Causes of Iron Deficiency without Anemia
The causes of iron deficiency without anemia (IDWA) can be attributed to several factors, including:
- Impaired nutrition 2
- Reduced absorption secondary to gastrointestinal conditions 2, 3
- Increased blood loss 2, 4, 3
- Increased needs, such as during pregnancy 2, 4, 5
- Chronic inflammatory conditions 4, 6
- Heavy menstrual bleeding 6, 3
- Surgery or preoperative conditions 4, 6, 5
Specific Causes
Some specific causes of IDWA include:
- Iron malabsorption due to atrophic gastritis, celiac disease, or chronic inflammation 3
- Chronic blood loss due to gastrointestinal ulcerations 3
- Benign gastrointestinal causes, such as bariatric surgery 3
- Malignant disease of the gastrointestinal tract, although this is less common 3
Diagnosis and Treatment
Diagnosing IDWA relies on a combination of tests, including hemoglobin and ferritin levels, as well as transferrin saturation 4. Treatment for IDWA typically involves oral iron supplementation, although intravenous iron therapy may be necessary in certain cases, such as intestinal malabsorption or prolonged inflammation 4, 6, 3.