HOW DOES VITAMIN B12 DIFFER FROM IRON DEFICIENCY?

Vitamin B12 deficiency and iron deficiency can both cause anemia and fatigue but they differ significantly in cause, blood picture, symptoms, and long-term risks.

🔎 Core Difference

	Vitamin B12 Deficiency	Iron Deficiency
Main function	DNA synthesis & nerve health	Hemoglobin production (oxygen transport)
Type of anemia	Macrocytic (large red blood cells)	Microcytic (small red blood cells)
Nervous system involvement	✅ Yes	❌ No
Risk of permanent damage	Yes (if untreated)	Rare

🩸 1.  Iron Deficiency

What Happens?

Iron is required to produce hemoglobin. Without enough iron, red blood cells become small and pale, reducing oxygen delivery.

Common Causes

• Heavy menstrual bleeding
• Pregnancy
• Gastrointestinal bleeding
• Poor dietary intake
• Malabsorption

Symptoms

• Fatigue
• Pale skin
• Shortness of breath
• Hair loss
• Brittle nails
• Craving ice or non-food items (pica)

👉 Key Feature: No neurological symptoms.

🧠 2.  Vitamin B12 Deficiency

What Happens?

Vitamin B12 is essential for:

• Red blood cell formation
• DNA production
• Myelin (nerve protection)

Without B12, red blood cells become large and fragile, and nerves begin to malfunction.

Common Causes

• Vegetarian/vegan diet
• Pernicious anemia
• Long-term metformin use
• Low stomach acid
• Gut disorders (e.g., Crohn’s disease)

Symptoms

• Fatigue
• Pale or slightly yellowish skin
• Tingling or numbness in hands and feet
• Memory problems
• Balance difficulty
• Mood changes

👉 Key Feature: Neurological symptoms (tingling, numbness, cognitive issues).
⚠️ If untreated, nerve damage can become permanent.

🔬 Blood Test Differences

Test	Iron Deficiency	B12 Deficiency
Hemoglobin	Low	Low
MCV (cell size)	Low	High
Ferritin	Low	Normal
Serum B12	Normal	Low

🎯 Quick Clinical Clues

• Tingling + anemia → Think B12
• Hair loss + heavy periods → Think iron
• Glossy smooth tongue → Often B12
• Craving ice → Classic iron deficiency

⚠️ Important Note

Both deficiencies can coexist — especially in:

• Elderly individuals
• People with malabsorption
• Vegetarians
• Chronic disease patients