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Vitamin B12 Deficiency

Insufficiency of a vitamin essential for the nervous system and blood cell production

Written by: Saygı Hospital Health Guide Editorial Board
Last updated:

This content has been compiled by the Saygı Hospital Health Guide Editorial Board and is periodically reviewed by a specialist physician.

References (5)

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our Dahiliye (İç Hastalıkları) department. Book Appointment →

What is Vitamin B12 Deficiency?

Vitamin B12 (cobalamin) is essential for DNA synthesis, myelin integrity of nerve fibres, and red blood cell maturation.

B12 is found naturally only in animal-source foods (meat, dairy, eggs, fish); vegans are therefore at particular risk without supplementation.

Absorption requires intrinsic factor, produced by gastric parietal cells. Pernicious anaemia (autoimmune destruction), gastric surgery, atrophic gastritis, prolonged metformin or PPI use, and ageing impair absorption.

The deficiency is insidious — symptoms may go unnoticed for years. Prompt diagnosis prevents irreversible neurological damage.

Symptoms

Fatigue, weakness, and pallor
Numbness and tingling in hands and feet (peripheral neuropathy)
Balance problems and gait difficulty
Memory impairment and poor concentration
Glossitis (sore inflamed tongue) and mouth ulcers
Depression, irritability, and personality change
Jaundice in severe haemolysis

Risk Factors

Vegan or strict vegetarian diet without supplementation
Age over 60 years (reduced gastric acid)
Pernicious anaemia
Long-term metformin use
Previous gastric or small bowel surgery
Chronic alcohol use
Long-term proton-pump inhibitor (PPI) therapy

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

  • If numbness or tingling develops in hands or feet
  • If balance or gait problems are noticed
  • If memory or concentration declines significantly
  • If megaloblastic anaemia is reported on blood testing
  • If fatigue worsens during long-term metformin therapy

Treatment Methods

01
Intramuscular hydroxocobalamin injections, especially for malabsorption
02
High-dose oral B12 (1000-2000 µg daily) for patients with preserved absorption
03
Treatment of the underlying cause (pernicious anaemia, drug effects)
04
Lifelong supplementation in vegans and after gastric surgery
05
Neurology referral if neurological symptoms persist
06
Regular monitoring of serum B12, MMA, and homocysteine

Which Department to Visit?

You can visit our Dahiliye (İç Hastalıkları) department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

Learn About Dahiliye (İç Hastalıkları) Department

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Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.