Vitamin B12 Deficiency: Causes and Treatments
Understand the causes, symptoms, and treatments for Vitamin B12 deficiency. Learn how to prevent it with diet, supplements, and medical care to protect your nerves, brain, and energy levels.
Written by Dr. J T Hema Pratima
Reviewed by Dr. Shaik Abdul Kalam MD (Physician)
Last updated on 8th Aug, 2025
Introduction
Vitamin B12 is an essential nutrient that keeps your nerves healthy, helps produce red blood cells, and supports brain function. However, many people suffer from a deficiency without even realising it. If left untreated, low B12 levels can lead to serious health problems.
In this article, we’ll discuss:
What Vitamin B12 deficiency is
Common symptoms to watch for
Causes of deficiency
How it affects your health
Treatment and prevention tips
What is Vitamin B12 Deficiency?
Vitamin B12 (also called cobalamin) is a water-soluble vitamin that your body cannot produce on its own—you must get it from food or supplements. A deficiency occurs when your body doesn’t get enough B12 or struggles to absorb it properly.
Since B12 plays a crucial role in nerve function and blood cell production, a deficiency can lead to fatigue, nerve damage, and even anaemia.
Symptoms of Vitamin B12 Deficiency
The signs of B12 deficiency can develop slowly and may be mistaken for other conditions. Common symptoms include:
Fatigue and weakness – Feeling unusually tired even after rest
Numbness or tingling – Especially in hands and feet (nerve damage sign)
Pale or yellowish skin – Due to low red blood cell production
Mouth ulcers or a sore tongue
Balance problems and dizziness
Memory issues or confusion – Can mimic dementia in severe cases
Mood changes – Depression or irritability
Vision problems – Blurred or disturbed vision
If you experience these symptoms for a long time, consult a doctor for a blood test.
Causes of Vitamin B12 Deficiency
Several factors can lead to low B12 levels:
1. Poor Dietary Intake
Vitamin B12 is mainly found in animal-based foods like:
Meat (beef, chicken, fish)
Eggs
Dairy products (milk, cheese, yoghurt)
Vegans and vegetarians who don’t consume enough fortified foods (like plant-based milk or cereals) are at higher risk.
Consult Top Specialists for Personalised Tips
2. Absorption Problems
Even if you eat enough B12, your body may not absorb it properly due to:
Pernicious anaemia – An autoimmune condition where the stomach can’t make intrinsic factor, a protein needed for B12 absorption.
Digestive disorders – Conditions like Crohn’s disease, celiac disease, or atrophic gastritis can interfere with absorption.
Stomach surgeries – Weight loss surgery or gastrectomy can reduce B12 absorption.
3. Medications That Reduce B12
Certain medications can lower B12 levels, including:
Metformin (for diabetes)
Proton pump inhibitors (PPIs) (for acid reflux, like omeprazole)
H2 blockers (for ulcers, like ranitidine)
4. Age-Related Decline
As we age, stomach acid production decreases, making it harder to absorb B12 from food.
How B12 Deficiency Affects Your Health
If untreated, a B12 deficiency can lead to:
Megaloblastic anaemia – Large, abnormal red blood cells that can’t function properly, causing extreme fatigue.
Nerve damage – Tingling, numbness, and even difficulty walking.
Cognitive decline – Memory loss, confusion, and increased dementia risk.
Mood disorders – Depression and anxiety.
Heart problems – Elevated homocysteine levels (linked to heart disease).
Diagnosis and Treatment
Diagnosis
A simple blood test can check your B12 levels. If you have symptoms, your doctor may also test for:
Methylmalonic acid (MMA) – High levels indicate B12 deficiency.
Homocysteine – Another marker for deficiency.
Treatment Options
1. Dietary Changes
Increase B12-rich foods like:
Fish (salmon, tuna)
Lean meats (chicken, turkey)
Eggs and dairy
Fortified cereals and plant-based milk (for vegans)
2. B12 Supplements
Oral tablets – Effective for mild deficiencies.
Sublingual (under-the-tongue) tablets – Better absorption for some people.
3. B12 Injections
If you have severe deficiency or absorption issues, your doctor may prescribe B12 injections (cyanocobalamin or hydroxocobalamin).
4. Treating Underlying Causes
If a medical condition (like pernicious anaemia) is causing the deficiency, treating that condition is crucial.
Prevention Tips
Eat a balanced diet with enough B12 sources.
Take supplements if you’re vegan, elderly, or have absorption issues.
Get regular check-ups if you’re on long-term medications (like PPIs or metformin).
Avoid excessive alcohol, which can worsen the deficiency.
When to See a Doctor?
If you experience persistent fatigue, numbness, memory issues, or other symptoms, consult a doctor. Early diagnosis and treatment can prevent complications.
Need Help? Book a Consultation or Test with Apollo 24|7
If you suspect a B12 deficiency, Apollo 24|7 offers:
At-home blood tests for B12 levels
Online doctor consultations for expert advice
Prescription supplements or injections if needed
Book a Test or Consultation Now
Final Thoughts
Vitamin B12 deficiency is common but often overlooked. Recognising the symptoms early and getting the right treatment can help you stay healthy and energetic. Whether through diet, supplements, or medical care, maintaining proper B12 levels is essential for your overall well-being.
Consult Top Specialists
Consult Top Specialists for Personalised Tips
Dr Suseela
General Physician
5 Years • MBBS
Bengaluru
Apollo Medical Center, Marathahalli, Bengaluru
Dr. Rajib Ghose
General Practitioner
25 Years • MBBS
East Midnapore
VIVEKANANDA SEBA SADAN, East Midnapore
Dr. Mainak Baksi
General Practitioner
13 Years • MBBS , MD (MPH)
Howrah
Mainak Baksi Clinic, Howrah
(50+ Patients)
Dr. Bulbul Biswas
General Practitioner
35 Years • MBBS, Diploma in Maternity and child welfare
Kolkata
HERSTEL CARE CLINIC, Kolkata
Dr. Dixant Chhikara
General Practitioner
4 Years • MBBS
Delhi
SKYNN CARE, Delhi
Consult Top Specialists
Dr Suseela
General Physician
5 Years • MBBS
Bengaluru
Apollo Medical Center, Marathahalli, Bengaluru
Dr. Rajib Ghose
General Practitioner
25 Years • MBBS
East Midnapore
VIVEKANANDA SEBA SADAN, East Midnapore
Dr. Mainak Baksi
General Practitioner
13 Years • MBBS , MD (MPH)
Howrah
Mainak Baksi Clinic, Howrah
(50+ Patients)
Dr. Bulbul Biswas
General Practitioner
35 Years • MBBS, Diploma in Maternity and child welfare
Kolkata
HERSTEL CARE CLINIC, Kolkata
Dr. Dixant Chhikara
General Practitioner
4 Years • MBBS
Delhi
SKYNN CARE, Delhi
