Vitamin B12 Deficiency: Common Questions

Vitamin B12 Deficiency: the questions people actually ask, answered from published guidance.

Key takeaways

• Common causes: pernicious anaemia, vegan diet, metformin, long-term PPIs, gastric surgery
• Neurological symptoms: numbness, tingling, balance problems, memory change
• Most useful single change: Ask for B12 testing if you have tingling, numbness or balance problems.
• Commonest mistake: Taking folic acid alone when B12 status is unknown.
• See a doctor if any of the signs under "When to get help" below apply to you.

What is Vitamin B12 Deficiency?

Insufficient B12 for red cell production and nerve maintenance.

Why does it matter?

The neurological damage can become permanent, and it can develop before anaemia appears, so waiting for a low haemoglobin is waiting too long.

Common causes for Vitamin B12 Deficiency?

Pernicious anaemia, vegan diet, metformin, long-term PPIs, gastric surgery.

Neurological symptoms for Vitamin B12 Deficiency?

Numbness, tingling, balance problems, memory change.

Pernicious anaemia for Vitamin B12 Deficiency?

Needs lifelong injections, not tablets.

Folic acid alone for Vitamin B12 Deficiency?

Can mask B12 deficiency while nerve damage continues.

What is the single most useful thing to do?

Ask for B12 testing if you have tingling, numbness or balance problems.

What is the most common mistake?

Taking folic acid alone when B12 status is unknown.

When should I see a doctor?

See a GP promptly for numbness or tingling in the hands or feet, unsteadiness, memory or personality change, or visual disturbance — neurological damage from B12 deficiency can become permanent if treatment is delayed. Seek urgent assessment for rapidly progressive weakness or difficulty walking.

Where to go next

• Myths About Vitamin B12 Deficiency, Checked Against the Guidance
• Vitamin B12 Deficiency for Beginners: Where to Start
• Vitamin B12 Deficiency — the reference entry
• The Evidence on Blood Clots, Without the Hype
• Anticoagulants: What Published Guidance Supports

When to get help

See a GP promptly for numbness or tingling in the hands or feet, unsteadiness, memory or personality change, or visual disturbance — neurological damage from B12 deficiency can become permanent if treatment is delayed. Seek urgent assessment for rapidly progressive weakness or difficulty walking.

Where this comes from

• NICE — Anaemia - B12 and folate deficiency clinical knowledge summary
• NHS — Vitamin B12 deficiency anaemia

How this page was put together

Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarised or generalised beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.

Medical disclaimer

This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to a GP, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 999.