Vitamin B12: Deficiency, Causes & Complications

Many people lack vitamin B12 in their bodies which affects their nerves and causes psychological problems in your body.

Sushmita Sharma
Written by: Sushmita SharmaUpdated at: Jan 01, 2023 18:00 IST
Vitamin B12: Deficiency, Causes & Complications

Vitamin B12 is vital for our body and its deficiency can lead to physical, neurological and also psychological problems. It is responsible for making red blood cells, energy production and carrying other functions in your body. Keep reading to know the symptoms, complications and prevention of vitamin B12 deficiency.

Vitamin B12 & Cause Of Deficiency

It is a water-soluble vitamin found in meat, dairy, and eggs. Its deficiency can occur when you don’t consume enough vitamin B12, or your body does not absorb or store the required amount of vitamin.


Inadequate consumption

It is usually common in vegetarians or vegans who do not take any supplements. Vitamin B12 deficiency may also occur in an infant who is breastfed by a vegan mother.

Inadequate Absorption

It can happen due to the following reasons.

  • An inflammatory bowel disease that affects the last part of the small intestine.
  • Bacteria overgrowth in the small intestine.
  • Fish tapeworm absorption
  • Decrease in stomach acidity, which is common in older people
  • AIDS

Also Read: Expert Talk: How Vitamin B12 Deficiency Could Be Wreaking Havoc On Your Mood

Symptoms Of Vitamin B12 Deficiency

  • Pale skin
  • Weakness
  • Smooth tongue
  • Constipation or diarrhoea
  • Loss of appetite
  • Loss of vision
  • Shortness of breath

Complications & Illness


Vitamin B12 deficiency can cause anaemia. Symptoms of anaemia include paleness, weakness, fatigue, shortness of breath, and a rapid heart rate.

Neurological Damage

Deficiency of this vitamin can lead to neurological symptoms like confusion, numbness, and tingling in hands and feet. It can hamper your memory and cause problems with balance. It can cause damage to the nerves and spinal cord and affect your mental health.

Affects Brain

Vitamin B12 deficiency can also affect the health of your brain and increase the risk of cognitive decline. It may also cause irritability, memory loss, depression, and dementia.

Cardiac Disease

Diseases like coronary artery disease and peripheral vascular are generally witnessed in people with low vitamin b12 levels. 

Pregnancy Issues

Vitamin B12 deficiency can cause foetal anomalies in pregnant women. It is advisable to get vitamin B12 checked in your body.

Also Read: 5 Signs and Symptoms of Vitamin B12 Deficiency

Worm Infection

There can be a decrease in vitamin B12 absorption when you have helminthic infections. It is due to increased gastric motility and hyperoxia.

How To Diagnose Vitamin B12 Deficiency

To diagnose this deficiency, your doctor will ask you about the symptoms and perform a physical examination to diagnose this deficiency. You will be asked to do a blood test to detect vitamin B12 levels in your body.

Food Sources Rich In Vitamin B12

  • Eggs
  • Fish
  • Clams
  • Beef Liver
  • Dairy products
  • Fortified Yeast


Vitamin B12 deficiency can be prevented by eating meat, poultry, seafood, eggs, and milk products. If you are on a plant-based diet, include fortified breakfast cereals, soy milk and nutritional yeast. You can ask your doctor to provide you with supplements or multivitamins. 


Take necessary measures if you detect any symptoms of vitamin B12 deficiency. Adopt lifestyle changes like limiting alcohol intake and increasing consumption of dairy products. Immediately seek help from your doctor if the condition worsens.