From the Guidelines
Iron deficiency without anemia is a condition where the body's iron stores are depleted, but hemoglobin levels remain normal, and it can have negative implications for aerobic performance, particularly in athletes 1. This condition, also called latent iron deficiency or non-anemic iron deficiency, represents an early stage of iron depletion before it progresses to iron deficiency anemia.
Key Points
- Iron deficiency is defined as low serum ferritin (<35 μg/L) and normal blood haemoglobin values 1.
- Common symptoms include lethargy, reduced performance, fatigue, weakness, difficulty concentrating, hair loss, brittle nails, and restless legs syndrome.
- Diagnosis typically involves blood tests showing low ferritin (iron storage protein) but normal hemoglobin.
- Treatment usually consists of a diet rich in iron, particularly red meat, to avoid the development of overt anemia and ensure that other haem-containing proteins/enzymes can be maintained at a sufficient level 1.
- A period of iron supplementation may be considered at levels above the RDA after consultation with qualified medical and dietetic practitioners 1.
Important Considerations
- The bioavailability of dietary iron is substantially lower in vegetarian diets than meat-based diets, so a well-planned diet is crucial to prevent iron deficiency 1.
- Vitamin C should be co-ingested with non-haem iron sources to enhance absorption, and foods or fluids that impair iron absorption, such as tea and coffee, should be avoided around meal times 1.
- Iron deficiency is more common in female athletes, with a prevalence of about 15%–35%, and regular blood screening is recommended to identify iron deficiency early 1.
From the Research
Definition and Prevalence
- Iron deficiency without anemia, also known as non-anemic iron deficiency, is a condition where the body has low iron stores but not low enough to cause anemia 2, 3.
- It is estimated that iron deficiency without anemia is at least twice as common as iron deficiency anemia, affecting approximately 2 billion people worldwide 2, 3.
Symptoms and Diagnosis
- Individuals with iron deficiency without anemia may experience symptoms such as fatigue, irritability, depression, difficulty concentrating, restless legs syndrome, and pica 2, 4.
- Diagnosis is typically made by measuring serum ferritin and transferrin saturation levels, with low ferritin (<30 ng/mL) and transferrin saturation (<20%) indicating iron deficiency 2, 5.
Causes and Risk Factors
- Common causes of iron deficiency without anemia include bleeding (menstrual, gastrointestinal), impaired iron absorption (atrophic gastritis, celiac disease, bariatric surgical procedures), inadequate dietary iron intake, and pregnancy 2, 3.
- Risk factors include use of nonsteroidal anti-inflammatory drugs, inflammatory bowel disease, chronic kidney disease, heart failure, and cancer 2, 3.
Treatment and Management
- Oral iron supplements are typically the first-line treatment for iron deficiency without anemia, with intravenous iron reserved for patients who do not respond to oral therapy or have certain chronic inflammatory conditions 2, 5.
- Identifying and managing the underlying cause of iron deficiency is also crucial in preventing further iron loss and improving symptoms 2, 3.