Iron Deficiency Management

Patient Populations and Iron Absorption

Chronic inflammatory conditions, such as inflammatory bowel disease, can affect iron absorption and management, according to the European Crohn’s and Colitis Organisation 1
Taking iron with food can decrease absorption, except when needed to improve tolerability, as noted by the American Gastroenterological Association 2
Enteric-coated formulations may improve tolerability but decrease absorption, as reported by the American Gastroenterological Association 2
Active inflammation in inflammatory bowel disease, post-bariatric surgery, and chronic heart failure are conditions that affect iron absorption, as reported by the American Gastroenterological Association and the European Society of Gastroenterology 3, 4, 5

Ferritin levels can be interpreted as follows:

Ferritin Level	Interpretation
<30 μg/L	Definitive iron deficiency
30-100 μg/L with transferrin saturation <20%	Possible iron deficiency, especially with inflammation
>100 μg/L with normal transferrin saturation	Iron deficiency is unlikely [6, 7, 1, 8]

A transferrin saturation <16% is considered diagnostic of iron deficiency, regardless of ferritin level 9
Essential tests for iron deficiency include serum ferritin and transferrin saturation, calculated from iron and total iron binding capacity, as recommended by the American Academy of Sleep Medicine 10
Additional markers of iron deficiency include hypochromic, microcytic red cells, low cellular Hb content in reticulocytes, and increased percentage of hypochromic RBCs, as stated by the Annals of Oncology 11
Ferritin is an acute phase reactant and may be falsely elevated with inflammation, according to the Annals of Oncology 11
In cancer and other inflammatory conditions, the ferritin cutoff should be raised to 100 ng/mL, as recommended by the Annals of Oncology 11

The first-line oral treatment for iron deficiency anemia is ferrous sulfate 50-100 mg of elemental iron once daily, taken in the morning on an empty stomach, continued for 3 months after hemoglobin normalization, as recommended by the European Society of Gastroenterology and the American Gastroenterological Association 12, 3, 13
Iron supplementation should be given between meals to maximize absorption 14

The recommended daily iron intake varies by population:

Population	Daily Iron Intake
Nonpregnant women and adolescent girls	60-120 mg
School-age children	60 mg
Adolescent boys	120 mg
Pregnant women (preventive supplementation)	30 mg
Pregnant women (treatment of anemia)	60-120 mg [14, 15, 12]

The American Academy of Pediatrics recommends iron supplementation at a dose of 3 mg/kg/day of elemental iron for infants with iron deficiency anemia 14
Preterm or low-birthweight infants should receive 2-4 mg/kg/day (maximum 15 mg/day) starting at 1 month after birth until 12 months 14
Breast-fed infants with insufficient iron from supplementary foods should receive 1 mg/kg/day of iron drops 14
Children aged 1-18 years should receive 50-100 μg/kg/day up to a maximum of 5 mg/day 16

Indications for intravenous iron supplementation include oral iron intolerance, poor absorption, chronic inflammatory conditions, ongoing blood loss, and ferritin levels between 75-100 ng/mL in patients with restless legs syndrome, as stated by the American Academy of Sleep Medicine 10
IV iron is preferred in patients with inflammatory bowel disease when active inflammation is present, and improves exercise capacity and quality of life in patients with iron deficiency and mild to moderate heart failure, as reported by the American Gastroenterological Association and the European Society of Gastroenterology 3, 4, 5
Ferric maltol may be considered for patients with inflammatory bowel disease or previous intolerance to iron salts, as suggested by the European Society of Gastroenterology 12

Regular monitoring of iron status (ferritin and hemoglobin) is recommended for patients on long-term treatment 16
Hemoglobin response should be monitored within the first 4 weeks of starting therapy, as recommended by the European Society of Gastroenterology 12
Treatment should be continued for approximately 3 months after hemoglobin normalizes to replenish iron stores, as suggested by the European Society of Gastroenterology and the American Gastroenterological Association 12, 15, 3
Blood count should be monitored periodically (every 6 months initially) to detect recurrent iron deficiency anemia, as recommended by the European Society of Gastroenterology 12
Hemoglobin and ferritin levels should be monitored regularly until normalized, with a target ferritin >100 μg/L to ensure adequate iron stores are replenished, as recommended by the Gut guideline and the American Gastroenterological Association 15, 12, 8, 1

Children with high gastrointestinal fluid losses may have significantly higher iron requirements 16
The Clinical Nutrition society recommends using iron sucrose as the preferred formulation in children due to its safety profile and few adverse events 16
Iron dextran should be avoided due to a higher risk of allergic reactions 16
Excessive blood transfusions should be avoided and reserved for severe symptomatic anemia, instead opting for IV iron therapy, as emphasized by the American Gastroenterological Association and the European Society of Gastroenterology 3, 4
Failing to continue iron therapy for the full 3 months after hemoglobin normalization, neglecting to investigate the cause of iron deficiency, and assuming that periods of improved appearance indicate resolution of the anemia are common mistakes to avoid, as warned by the Gut guideline and the American Gastroenterological Association 12, 3