Vitamin B12 deficiency

Vitamin B12 is important for the blood, nerve cells and cell renewal.


Vitamin B12 is important for the blood, nerve cells and cell renewal. It can't be produced by the body, and deficiencies occur, for example, with vegan diets. Possible symptoms include fatigue, tingling in the feet and a burning tongue. A balanced diet reduces the risk of a deficiency.


Main symptoms

  • Fatigue, pale skin (anaemia)
  • Numbness or tingling in the feet, more rarely in the hands
  • Burning tongue, red and smooth tongue

Other symptoms

  • Mouth ulcers, diarrhoea, stomach cramps
  • Weight gain
  • Frequent infections
  • Heavier or prolonged bleeding
  • Uncertain gait, deterioration of vision, bladder disorders
  • Non-specific symptoms such as lack of appetite, feeling of weakness, lethargy, memory disorders, nervousness and sleep disorders

Causes and treatment


Vitamin B12 deficiency often builds up over time. Possible causes include:

  • Insufficient uptake: vegan diet, anorexia, chronic alcohol consumption, poor nutrition in advanced age (e.g. owing to lack of appetite)
  • Uptake disorders: gastritis, operation to remove parts of the stomach or intestine, chronic inflammation of the bowel (e.g. Crohn's disease, ulcerative colitis, coeliac disease)
  • Increased requirement: pregnancy, breastfeeding, newborn baby
  • Long-term use of medication: medication to reduce the production of stomach acid, diabetes medication, epilepsy medicatio
  • Long-term deficiency can cause lasting damage, e.g. paralysis or dementia, as well as a higher risk of stomach cancer.

Further treatment by your doctor / in hospital

Possible tests
  • Blood test and measurement of vitamin B12 levels
  • Search for the cause, e.g. gastroscopy if gastritis is suspected
Possible therapies
  • Treatment of the cause
  • Vitamin B12 supplements in the form of tablets or injections

What can I do myself?

A balanced diet is important if a vitamin B12 deficiency has been diagnosed. Good sources of vitamin B12 include:

  • Meat
  • Fish
  • Eggs
  • Dairy products


A balanced and varied diet is important for prevention. This will provide healthy people with sufficient vitamin B12. Strict vegetarians and vegans can eat special foods enriched with vitamin B12 (e.g. oat milk or soya yoghurt). These can mostly be found in health shops.

When to see a doctor?

The doctor should be consulted if you have been suffering from the following symptoms over a prolonged period:

  • Fatigue
  • Numbness in the feet
  • Burning tongue

Other possible causes, such as a deficiency in folic acid or iron, can be checked at the same time.


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Exclusion of liability

CSS offers no guarantee for the accuracy and completeness of the information. The information published is no substitute for professional advice from a doctor or pharmacist.