Anaemia, iron‑deficiency - Symptoms, Causes, Treatment & Prevention

Overview

Iron‑deficiency anaemia (IDA) is the most common form of anaemia worldwide. It occurs when the body lacks enough iron to produce hemoglobin—the protein in red blood cells that carries oxygen to tissues. Without sufficient hemoglobin, organs receive less oxygen, leading to the classic symptoms of fatigue, weakness, and shortness of breath.

Who is affected? IDA can affect anyone, but certain groups are at higher risk:

• Women of child‑bearing age (menstrual blood loss)
• Pregnant women (increased iron demand for the fetus)
• Infants and young children (rapid growth)
• People with chronic gastrointestinal disorders (e.g., celiac disease, inflammatory bowel disease)
• Individuals following strict vegetarian or vegan diets without adequate iron intake

According to the World Health Organization (WHO), about 1.24 billion people—roughly 15% of the global population—are affected by anaemia, and iron deficiency accounts for nearly 50% of these cases.^{WHO 2022} In the United States, the Centers for Disease Control and Prevention (CDC) estimates that ~5% of non‑pregnant women and 2% of men have iron‑deficiency anaemia.^{CDC 2023}

Symptoms

Symptoms may develop gradually and can be subtle at first. The severity usually correlates with how low the hemoglobin level has fallen.

• Fatigue & Weakness: A feeling of constant tiredness that does not improve with rest.
• Pallor: Noticeably paler skin, especially on the face, inner eyelids, and nail beds.
• Shortness of breath: Trouble catching breath during ordinary activities or exertion.
• Rapid or irregular heartbeat (tachycardia): The heart works harder to deliver oxygen.
• Dizziness or Light‑headedness: Especially when standing quickly.
• Headaches: Often described as a dull, persistent ache.
• Cold hands and feet: Poor circulation from reduced oxygen delivery.
• Chest pain: Rare but can occur if the heart is strained.
• Hair loss & Brittle nails: Iron is essential for keratin production.
• Restless legs syndrome (RLS): Uncomfortable sensations in the legs that improve with movement.
• Glossitis & Angular cheilitis: Swollen, sore tongue and cracks at the corners of the mouth.
• Reduced appetite: Common in children, sometimes leading to growth delay.

Causes and Risk Factors

Primary Causes

1. Inadequate dietary intake: Consuming foods low in heme iron (the form most readily absorbed) such as meat, poultry, and fish.
2. Increased iron requirements: Pregnancy, infancy, and adolescence are periods of rapid growth.
3. Chronic blood loss: The most common cause in adult women is heavy menstrual bleeding. Gastrointestinal bleeding from ulcers, hemorrhoids, colon polyps, or cancers can also lead to IDA.
4. Malabsorption: Conditions that damage the duodenum or proximal jejunum (e.g., celiac disease, bariatric surgery) reduce iron absorption.
5. Chronic inflammation: Inflammatory cytokines increase hepcidin, a hormone that blocks iron release from stores, leading to functional iron deficiency.

Risk Factors

• Female sex, especially menopausal‑pre (reproductive) age.
• Pregnancy or lactation.
• Low‑iron diet (vegetarian/vegan without fortified foods or supplements).
• History of gastrointestinal surgery (e.g., gastric bypass).
• Chronic kidney disease or heart failure.
• Use of certain medications: proton‑pump inhibitors, antacids, and NSAIDs that cause GI bleeding.
• Parasitic infections (hookworm) in endemic regions.

Diagnosis

Diagnosis involves a combination of clinical assessment and laboratory tests.

Initial Blood Work

• Complete Blood Count (CBC): Looks for low hemoglobin (Hb) and hematocrit (Hct), reduced mean corpuscular volume (MCV), and low red‑cell distribution width (RDW).
• Serum Ferritin: The most specific test for iron stores; low levels (<30 ng/mL) strongly suggest iron deficiency.
• Serum Iron, Total Iron‑Binding Capacity (TIBC), and Transferrin Saturation: Low serum iron, high TIBC, and <20% transferrin saturation are typical.
• Reticulocyte count: May be low or normal early in the disease.

Confirmatory/Additional Tests

• Peripheral Blood Smear: Shows microcytic, hypochromic red cells.
• Stool occult blood test: Screens for gastrointestinal bleeding.
• Endoscopy/Colonoscopy: Indicated if GI bleeding is suspected, especially in adults >50 years.
• Bone‑marrow biopsy: Rarely needed; iron‑staining of marrow can confirm deficiency.

Diagnostic Criteria (CDC/WHO)

For non‑pregnant women: Hb <12 g/dL; for men: Hb <13 g/dL; for pregnant women: Hb <11 g/dL. Combined with low ferritin and/or transferrin saturation confirms IDA.^{CDC 2023}

Treatment Options

Iron Supplementation

• Oral ferrous salts: Ferrous sulfate (325 mg tablet ≈ 65 mg elemental iron) is first‑line. Alternatives include ferrous gluconate and ferrous fumarate.
• Typical dose: 150–200 mg elemental iron daily, divided into two or three doses.
• Take on an empty stomach with water or vitamin C‑rich juice to enhance absorption; avoid calcium, tea, coffee, or antacids within 2 hours.
• Common side effects: constipation, nausea, dark stools. If poorly tolerated, switch to a slower‑release preparation or a lower dose.

Parenteral Iron

Intravenous (IV) iron is reserved for:

• Severe IDA (Hb <7 g/dL) or symptomatic patients who cannot wait for oral therapy.
• Intolerance or malabsorption of oral iron.
• Chronic kidney disease on dialysis.

Products include iron sucrose, ferric carboxymaltose, and iron dextran. A typical adult dose ranges from 500 mg to 1 g per infusion, administered over 15–30 minutes.^{Mayo Clinic}

Treat Underlying Cause

• Control menstrual bleeding (e.g., hormonal contraceptives, tranexamic acid).
• Manage GI sources (ulcer treatment, polyp removal, eradication of H. pylori).
• Address malabsorption (gluten‑free diet for celiac disease, postoperative nutrition counseling).

Adjunctive Measures

• Vitamin C (ascorbic acid): 500 mg with iron tablets improves absorption.
• Dietary changes: Increase intake of heme iron (red meat, poultry, fish) and non‑heme iron (lentils, beans, fortified cereals) while pairing with vitamin C‑rich foods.
• Folic acid supplementation: Often given concurrently to ensure adequate DNA synthesis during erythropoiesis.

Living with Anaemia, Iron‑Deficiency

Daily Management Tips

1. Adhere to supplement schedule: Set a reminder; take with a glass of orange juice.
2. Monitor side effects: If constipation occurs, increase fiber (whole grains, fruits) and fluid intake.
3. Track your hemoglobin: Repeat CBC at 4‑6 weeks after starting therapy, then every 3 months until stable.
4. Balanced meals: Pair iron‑rich foods with vitamin C (e.g., spinach salad with strawberries) and avoid calcium‑rich foods at the same meal.
5. Physical activity: Light to moderate exercise improves cardiovascular fitness, but listen to your body—avoid overexertion that provokes dizziness.
6. Travel considerations: Carry a short supply of iron tablets and a copy of your lab results when flying internationally.

When to Call Your Provider

• Symptoms persist or worsen after 4 weeks of therapy.
• Severe constipation, black stools, or vomiting after taking iron.
• New onset chest pain, rapid heartbeat, or shortness of breath at rest.

Prevention

• Eat a varied diet: Include lean red meat 2–3 times per week, poultry, fish, legumes, nuts, and dark leafy greens.
• Combine non‑heme iron sources (e.g., beans) with vitamin C (citrus fruit, bell peppers).
• Limit tea, coffee, and high‑calcium foods during iron‑rich meals.
• Women with heavy menstrual bleeding should discuss hormonal or surgical options with a gynecologist.
• Pregnant women should begin prenatal vitamins with iron early in pregnancy as recommended by OB‑GYN.
• Screen at‑risk populations (infants, adolescents, chronic kidney disease patients) with a CBC at regular intervals.

Complications

If untreated, iron‑deficiency anaemia can lead to:

• Severe fatigue and reduced work/school performance.
• Cardiovascular strain: Tachycardia, left‑ventricular hypertrophy, or heart failure in long‑standing severe cases.
• Pregnancy outcomes: Preterm delivery, low birth weight, and impaired neurodevelopment in the infant.^{CDC Pregnancy}
• Immune dysfunction: Lowered resistance to infections.
• Growth retardation in children.

When to Seek Emergency Care

References

1. World Health Organization. Anaemia Fact Sheet. 2022.
2. Centers for Disease Control and Prevention. Anemia FastStats. 2023.
3. Mayo Clinic. Iron‑deficiency anemia – Diagnosis and treatment. Updated 2024.
4. American College of Gastroenterology. Guidelines for evaluation of GI‑related anemia. 2023.
5. Cleveland Clinic. Iron‑deficiency anemia. Reviewed 2024.
6. National Institutes of Health. Iron – Health Professional Fact Sheet. 2023.