From the Guidelines
Iron deficiency without anemia should be treated with oral iron supplementation, typically ferrous sulfate 325 mg daily or twice daily, taken on an empty stomach with vitamin C to enhance absorption, as recommended by the most recent and highest quality study 1.
Treatment Overview
Treatment of iron deficiency without anemia aims to replenish iron stores and improve quality of life. The goal is to increase iron intake and absorption, while addressing the underlying cause of the deficiency.
Oral Iron Supplementation
- Ferrous sulfate 325 mg daily or twice daily is the recommended oral iron supplement 1.
- Alternative options include ferrous gluconate 300 mg or ferrous fumarate 200 mg if side effects occur.
- Treatment should continue for 3-6 months to fully replenish iron stores, with follow-up ferritin testing to confirm improvement.
Dietary Recommendations
- Patients should avoid taking iron with calcium, dairy, coffee, tea, or antacids, which reduce absorption.
- Vitamin C should be co-ingested with non-haem iron sources to enhance absorption.
- Foods or fluids that impair iron absorption, such as tea and coffee, should be avoided around meal times.
Addressing Underlying Causes
- Addressing the underlying cause of iron deficiency is essential, whether it's blood loss, poor dietary intake, malabsorption, or increased requirements during pregnancy.
- Iron deficiency without anemia can cause fatigue, reduced exercise capacity, hair loss, and restless legs syndrome even before anemia develops, as iron is crucial for many bodily functions beyond hemoglobin production, including cellular energy production, neurotransmitter synthesis, and immune function 1.
Monitoring and Follow-up
- Follow-up ferritin testing is necessary to confirm improvement and adjust treatment as needed.
- Patients with inflammatory conditions may require additional testing, such as transferrin saturation, soluble transferrin receptor, or reticulocyte hemoglobin equivalent, to confirm iron deficiency 1.
From the Research
Definition and Prevalence
- Iron deficiency without anemia (IDWA) is a condition where the body has low iron stores, but not low enough to cause anemia 2.
- IDWA is at least twice as common as iron deficiency anemia (IDA), affecting a significant proportion of the population, particularly adolescents and menstruating females 2, 3.
- Approximately 38% of nonpregnant, reproductive-age women have iron deficiency without anemia, and about 13% have iron-deficiency anemia in high-income countries 4.
Causes and Risk Factors
- The most common causes of iron deficiency are bleeding (menstrual, gastrointestinal), impaired iron absorption (atrophic gastritis, celiac disease, bariatric surgical procedures), inadequate dietary iron intake, and pregnancy 4.
- Additional risk factors include use of nonsteroidal anti-inflammatory drugs, inflammatory bowel disease (IBD), and other chronic inflammatory conditions, such as chronic kidney disease (CKD), heart failure (HF), and cancer 4.
Diagnosis
- Iron deficiency is diagnosed by low serum ferritin (typically <30 ng/mL) in individuals without inflammatory conditions or by transferrin saturation (iron/total iron binding capacity × 100) less than 20% 4.
- A baseline set of blood tests, including haemoglobin concentration, haematocrit, mean cellular volume, mean cellular haemoglobin, percentage of hypochromic erythrocytes, and serum ferritin levels, are important to monitor iron deficiency 2.
- An acute phase reaction should be excluded by history and measurement of C-reactive protein to avoid false negative results 2.
Treatment
- Oral iron supplementation is the first-line treatment for managing IDWA, with ferrous sulfate 325 mg/d or on alternate days being a common regimen 4.
- Intravenous iron supplementation is indicated for patients with oral iron intolerance, poor absorption, chronic inflammatory conditions, ongoing blood loss, and during the second and third trimesters of pregnancy 4, 3.
- Counselling and oral iron therapy are usually combined as a first step in treatment, with the goal of integrating haem and free iron regularly into the diet and avoiding inhibitors of iron uptake 2.