Vitamin B12 Deficiency
Low levels of vitamin B12 causing fatigue, neurological problems, and anemia.
Overview
Vitamin B12 deficiency occurs when your body doesn't have enough of this essential vitamin, which is crucial for nerve function, DNA synthesis, and red blood cell formation. Deficiency causes fatigue, weakness, and can lead to serious neurological damage if untreated. B12 is found mainly in animal products, making vegetarians and vegans at higher risk. Older adults and people with digestive conditions often can't absorb B12 properly even with adequate intake.
Common Age
More common in older adults; vegans of any age
Prevalence
Affects 1.5-15% depending on age and diet
Duration
Improves with treatment; some nerve damage may be permanent
Common Symptoms
- Extreme fatigue and weakness
- Pale or yellowish skin
- Shortness of breath
- Dizziness or lightheadedness
- Numbness or tingling in hands/feet
- Balance problems
- Cognitive changes (confusion, memory issues)
- Depression and mood changes
- Glossitis (swollen, red tongue)
- Mouth ulcers
- Vision disturbances
- Heart palpitations
Possible Causes
- Vegetarian or vegan diet without supplementation
- Pernicious anemia (autoimmune)
- Atrophic gastritis
- Digestive disorders (Crohn's, celiac)
- Gastric bypass surgery
- Long-term metformin use
- Chronic acid-reducing medications (PPIs)
- Age-related decreased absorption
- Alcohol abuse
- Tapeworm infection (rare)
Note: These are potential causes. A healthcare provider can help determine the specific cause in your case.
Quick Self-Care Tips
- 1Get B12 levels tested if fatigued
- 2Take supplements if at risk
- 3Vegans must supplement B12
- 4Choose fortified foods if plant-based
- 5Discuss with doctor if on metformin
- 6Consider sublingual or injection forms if absorption issues
- 7Don't delay treatment—nerve damage can be permanent
- 8Retest after supplementation
Disclaimer: These are general wellness suggestions, not medical treatment recommendations. They may help manage symptoms but should not replace professional medical care.
Detailed Treatment & Solutions
1ORAL SUPPLEMENTATION
High-dose oral B12 (1000-2000mcg daily) works for most dietary deficiencies. Cyanocobalamin or methylcobalamin forms. Continue long-term if cause persists.
2B12 INJECTIONS
For severe deficiency, absorption problems, or neurological symptoms. Weekly injections initially, then monthly maintenance. Bypasses absorption issues.
3DIETARY SOURCES
Animal products: meat, fish, eggs, dairy. Fortified foods: nutritional yeast, plant milks, cereals. Note: plant sources (spirulina, seaweed) contain inactive analogues.
4ADDRESS UNDERLYING CAUSE
Test for pernicious anemia (intrinsic factor antibodies). Treat digestive conditions. Review medications. Reduce alcohol.
5MONITOR NEUROLOGICAL SYMPTOMS
Nerve damage from B12 deficiency may be irreversible if prolonged. Tingling, numbness, and balance problems need urgent treatment.
6REGULAR MONITORING
Recheck B12 and complete blood count after 2-3 months of treatment. Adjust supplementation based on response.
Important: Always consult a healthcare professional before starting any treatment regimen. The solutions above are for educational purposes and may not be suitable for everyone.
Risk Factors
- Vegan/vegetarian diet
- Age over 50
- Gastric surgery
- Digestive disorders
- Metformin use
- Heavy alcohol use
Prevention
- Regular B12 supplementation for at-risk groups
- Fortified foods
- Regular screening if at risk
When to See a Doctor
Consult a healthcare provider if you experience any of the following:
- Persistent fatigue and weakness
- Numbness or tingling in extremities
- Balance or walking problems
- Cognitive changes or confusion
- You're vegan/vegetarian and haven't been supplementing
Talk to a Healthcare Provider
If your symptoms are persistent, severe, or concerning, please consult with a qualified healthcare professional for proper evaluation and personalized advice.
Frequently Asked Questions
QCan I get enough B12 from a vegan diet?
No, not without supplementation. B12 is not reliably found in plant foods. Vegans must take B12 supplements or eat fortified foods (nutritional yeast, fortified plant milks). This is not optional—B12 deficiency causes serious, potentially permanent nerve damage.
QHow long until I feel better after starting B12?
Energy and mood often improve within days to weeks of starting treatment. However, neurological symptoms (numbness, tingling) take longer to improve and may not fully resolve if deficiency was prolonged. Early treatment is important.
Related Conditions
Anemia (Low Iron)
A condition where you lack enough healthy red blood cells to carry adequate oxygen to your tissues.
Iron-Deficiency Anemia
A condition where lack of iron leads to insufficient healthy red blood cells.
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Medical Disclaimer
The information on this page is for educational purposes only and is not intended as medical advice. It should not be used for self-diagnosis or self-treatment. Always seek the guidance of a qualified healthcare professional with any questions you have regarding a medical condition. If you are experiencing a medical emergency, call your local emergency services immediately.
Information last reviewed: January 2026
This page provides educational information only. It is not medical advice.