Iron deficiency anaemia (IDA) occurs when your body does not have enough iron to produce adequate haemoglobin, the protein in red blood cells that carries oxygen. The World Health Organization estimates that anaemia affects approximately 1.62 billion people globally, with iron deficiency being the most common cause.
Why Is Iron Important?
Iron is essential for:
- Oxygen transport: Haemoglobin in red blood cells carries oxygen from the lungs to every cell in the body
- Energy production: Iron is needed for cellular energy metabolism
- Immune function: Adequate iron supports the immune system
- Brain function: Important for cognitive development and concentration
Symptoms
Symptoms develop gradually and may initially be subtle:
- Fatigue and weakness (the most common symptom)
- Pale skin, nail beds, and inside of eyelids
- Shortness of breath, especially on exertion
- Dizziness or lightheadedness
- Headache
- Cold hands and feet
- Brittle nails (may become spoon-shaped in severe cases)
- Restless legs syndrome
- Unusual cravings for non-food items (ice, clay, starch) - a condition called pica
- Rapid or irregular heartbeat
- Poor concentration and memory
- Frequent infections
Common Causes
Inadequate Iron Intake
- Insufficient iron-rich foods in the diet
- Vegetarian or vegan diets (plant-based iron is less well absorbed)
- Restrictive diets
Increased Iron Needs
- Pregnancy: Iron requirements increase significantly
- Growth: Infants, children, and adolescents have high iron needs
- Breastfeeding
Blood Loss
- Menstruation: Heavy periods are the most common cause of IDA in women of reproductive age
- Gastrointestinal bleeding: Ulcers, polyps, inflammatory bowel disease, or in rare cases, bowel cancer
- Frequent blood donation
Poor Iron Absorption
- Coeliac disease
- Inflammatory bowel disease (Crohn's, ulcerative colitis)
- Gastric surgery
- Medications (e.g., proton pump inhibitors can reduce iron absorption)
Diagnosis
Blood Tests
- Full blood count (FBC): Shows low haemoglobin and small, pale red blood cells (microcytic, hypochromic)
- Serum ferritin: The best indicator of iron stores. Low ferritin (below 15 micrograms/L) confirms iron deficiency
- Serum iron, transferrin, and transferrin saturation: Additional markers
- Inflammatory markers (CRP): Ferritin can be falsely elevated in inflammation
Finding the Cause
NICE recommends investigating the underlying cause of iron deficiency anaemia to exclude serious conditions including gastrointestinal malignancy, especially in:
- Men of any age with iron deficiency anaemia
- Post-menopausal women
- When there is no obvious dietary or menstrual cause
This may include:
- Coeliac disease screening (tissue transglutaminase antibody)
- Urine testing for blood
- Referral for endoscopy (to examine the stomach and bowel) in appropriate cases
Treatment
Oral Iron Supplements
- First-line treatment: Ferrous sulphate, ferrous fumarate, or ferrous gluconate
- NICE recommends ferrous sulphate 200 mg twice or three times daily
- Take on an empty stomach with vitamin C (orange juice) to enhance absorption
- Common side effects: nausea, constipation, dark stools, stomach cramps
- If side effects are troublesome, try taking with food, reducing the dose, or switching to a different preparation
- Treatment duration: Continue for at least 3 months after haemoglobin normalises to replenish iron stores
Dietary Iron Sources
Haem iron (best absorbed, from animal sources):
- Red meat (beef, lamb)
- Poultry (chicken, turkey)
- Fish (tuna, sardines)
- Liver
Non-haem iron (from plant sources):
- Lentils and beans
- Chickpeas
- Spinach and dark leafy greens
- Tofu
- Fortified cereals and bread
- Dried fruits (apricots, raisins)
- Nuts and seeds (pumpkin seeds, cashews)
Tips to Improve Iron Absorption
- Eat vitamin C-rich foods with iron-rich meals (citrus, tomatoes, bell peppers)
- Avoid tea and coffee with meals (tannins reduce iron absorption)
- Avoid calcium supplements with iron-rich meals
Intravenous Iron
Recommended when:
- Oral iron is not tolerated or ineffective
- Rapid correction is needed (e.g., severe anaemia, approaching surgery, late pregnancy)
- Absorption is impaired (e.g., inflammatory bowel disease)
When to See a Doctor
- Persistent fatigue that does not improve with rest
- Symptoms of anaemia as listed above
- Heavy menstrual periods
- If you are pregnant and have not had blood tests recently
- Blood in the stool or dark, tarry stools
This article is for informational purposes only and does not replace professional medical advice. Always consult your doctor for personalised guidance.