What is the appropriate dosage of iron supplement for an individual with iron deficiency?

Appropriate Dosage of Iron Supplements for Iron Deficiency

For individuals with iron deficiency, the recommended oral iron supplementation is 18-30 mg of elemental iron per day, with higher doses of 60-200 mg daily reserved for those with confirmed iron deficiency anemia or severe symptoms. 1

Diagnostic Assessment

• Full investigation of iron status should be performed in cases of anemia and persistent major fatigue 1
• Diagnostic workup should include:
  • Complete blood count
  • Serum ferritin
  • Transferrin saturation
  • C-reactive protein (to assess inflammation)
  • Evaluation of red blood cell morphology 1, 2
• Iron deficiency is confirmed by:
  • Serum ferritin <30 μg/L in the absence of inflammation
  • Serum ferritin <100 μg/L with concurrent inflammation
  • Transferrin saturation <16% 1, 2

Treatment Recommendations Based on Severity

Mild Iron Deficiency (Non-anemic or Mild Anemia)

• For enteral nutrition and general supplementation: 18-30 mg of elemental iron per day 1
• For mild anemia (Hb 11.0-11.9 g/dL in women, 11.0-12.9 g/dL in men) with clinically inactive disease: oral iron supplementation 1, 2
• Recommended oral dosing:
  • 100 mg elemental iron once daily in the morning for symptom-free patients 3, 4
  • Consider alternate-day dosing to improve absorption and reduce side effects 3, 5

Moderate to Severe Iron Deficiency Anemia

• For severe anemia (Hb <10 g/dL): intravenous iron is the preferred first-line treatment 1, 2
• For symptomatic patients: 200 mg elemental iron daily 4
• For women of reproductive age: minimum 18 mg/day, with active female soldiers recommended to consume at least 22 mg/day 1
• For parenteral nutrition: at least 1 mg/day of elemental iron 1

Administration Considerations

• Morning single doses are preferred over divided doses throughout the day 3, 5
• Alternate-day dosing (every 48 hours) improves fractional iron absorption compared to consecutive-day dosing 3, 5
• Take iron supplements with vitamin C-rich foods to improve absorption 1
• Avoid taking iron supplements within two hours of antibiotics as they may interfere with absorption 6
• Take with meals if gastrointestinal discomfort occurs 6

Special Populations

• Pregnant women and women with heavy menstrual bleeding require higher iron intake 1, 7
• Patients with inflammatory conditions (IBD, chronic kidney disease, heart failure):
  • IV iron is preferred over oral supplementation 1, 2
  • Oral iron may exacerbate intestinal inflammation 2
• Patients with low body weight (<40 kg): adjust the 1 mg/day dose accordingly 1

Monitoring Response

• Assess treatment response by repeating hemoglobin and iron studies after 8-10 weeks 1, 2
• Target hemoglobin level is above 12 g/dL 2
• Avoid checking ferritin levels too early after IV iron as they will be falsely elevated 1

Safety Considerations

• Do not exceed recommended dosage due to risk of iron overload 6
• Iron supplements are a leading cause of fatal poisoning in children under 6 - keep out of reach of children 6
• Common side effects include constipation, diarrhea, and nausea 1, 6
• Iron supplementation during infections should be balanced against potential adverse effects on disease course 1