Quick Answer
Vitamin B12 deficiency is a common, reversible cause of neuropathy symptoms — burning feet, tingling, balance problems and 'brain fog'. A simple blood test and treatment can prevent permanent nerve damage.
Medically reviewed by Dr. Jitendra Prasad Yadav • NMC 8029 • Kathmandu Neurology Clinic & Cognitive Center
Vitamin B12 is essential for nerve function, red blood cell production and DNA synthesis. Deficiency causes a range of neurological symptoms that are often misattributed to aging or stress —— and it is one of the few causes of nerve damage that is completely reversible if caught early. Unfortunately, it is also frequently missed because symptoms develop gradually.
Neurological symptoms of B12 deficiency
- Peripheral neuropathy: tingling, numbness, burning pain starting in the feet (stocking distribution).
- Balance problems: proprioceptive loss makes walking unsteady, especially in the dark.
- Cognitive changes: memory problems, confusion, 'brain fog' —— sometimes mistaken for early dementia.
- Weakness: muscle weakness, particularly in the legs.
- Mood changes: depression, irritability.
- Lhermitte's sign: electric-shock sensation down the spine on neck flexion (suggests spinal cord involvement).
Who is at risk?
Vegetarians and vegans (B12 is found only in animal products), older adults (reduced stomach acid impairs absorption), people with pernicious anemia (autoimmune inability to absorb B12), those who have had stomach or bowel surgery, chronic alcohol users, and anyone on metformin long-term (diabetes medication that reduces B12 absorption).
Diagnosis and treatment
Diagnosis is a simple blood test measuring serum B12, often with methylmalonic acid (MMA) for confirmation when levels are borderline. Treatment depends on the cause: oral or sublingual supplements for mild deficiency, and intramuscular injections for pernicious anemia or severe deficiency. Neurological symptoms typically improve over weeks to months with adequate replacement, though severe or long-standing deficiency may leave residual damage.
When to get tested
Test if you have tingling/numbness in feet or hands, unexplained balance problems, memory or cognitive changes, unexplained fatigue or anemia, are vegetarian/vegan, or take metformin or acid-reducing medications long-term. At neuropathy evaluation, B12 is one of the first tests ordered because it is common, cheap to test and completely treatable.
This guide is educational and does not replace individual medical advice.
Frequently asked questions
Answers reviewed by Dr. Jitendra Prasad Yadav • MBBS, MD (Internal Medicine), FICN (Neurology), FCNV, FIHM • NMC 8029
Supplements only help when a deficiency is present; underlying cause-directed care is needed.
If the underlying cause is corrected early (e.g., improving glucose control, treating vitamin deficiency), improvement may occur. Long-standing neuropathy is often not fully reversible.
Brief slips without functional impact are often benign; persistent, progressive interference with daily tasks warrants assessment.
Yes, anxiety, depression, and poor sleep frequently impair attention and recall and improve when treated.
More: All FAQs → · Ask Dr. Jitendra →
Related articles
Vitamin B12 Deficiency: Neurological Symptoms You Should Not Ignore — Kathmandu Guide
B12 deficiency causes neuropathy, cognitive symptoms, and anemia — especially common in Nepal's vegetarian population. Learn symptoms, causes, and treatment.
Understanding Lab Tests: B12, Thyroid and What Your Numbers Mean
A plain-language guide to common blood tests — B12, thyroid function, HbA1c, vitamin D — what they measure and what abnormal results mean.
When Numbness Needs Neurological Evaluation
Tingling, numbness, or burning in feet or hands —— length-dependent neuropathy patterns and what evaluation checks in Kathmandu.
Medical Disclaimer
Content on this website is for general educational purposes only and does not constitute medical advice, diagnosis, or treatment. It is not a substitute for evaluation by a qualified healthcare professional. Always seek the advice of your physician or other qualified provider with any questions regarding a medical condition. Never disregard professional medical advice or delay seeking it because of something you have read on this website. In case of a medical emergency, contact emergency services immediately. No doctor–patient relationship is established by use of this site or by contacting the clinic through the site.
References & Review
Reviewed by Dr. Jitendra Prasad Yadav • Last reviewed: 2026-11-10
- International Classification of Headache Disorders, 3rd edition (ICHD-3).
- Harrison's Principles of Internal Medicine — Neurology sections.
- American Academy of Neurology guidelines for selected conditions (where applicable).
Content is educational and aligns with standard medical references; individual evaluation may vary. External links provide context and do not imply endorsement.