Vitamin B12 Deficiency – Symptoms, Causes, Supplements, Injection

Vitamin B12 (cobalamin) is found in foods sourced from animals, like meat, eggs and milk. It plays an important role in the formation and maturation of red blood cells – the key carrier of gases in the blood. Vitamin B12 also helps cells to synthesise DNA and plays a key role in the structure and functioning of the nerves. The body stores about 2.5mg (milligrams) of vitamin B12 and adults only need approximately 2mcg (micrograms) per day while 0.7 mcg is sufficient for children.

Signs and Symptoms

When the level of vitamin B12 is low, many signs and symptoms may arise including :

  • anaemia
  • paleness
  • weakness
  • fatigue
  • low energy levels
  • shortness of breath
  • dizziness
  • numbness and tingling in the hands and feet
  • muscle weakness
  • poor reflexes
  • dementia in extreme cases

Causes of Vitamin B12 Deficiency

In most cases, a vitamin B12 deficiency arises from malnutrition, particularly in a vegans. Since the body stores large amounts of vitamin B12, a deficiency is not immediately evident. Vegetarians who consume sufficient amounts of milk and eggs (ovo-vegetarians) are less likely to suffer from a vitamin B12 deficiency. Vegans on the other hand are at the greatest risk and the only solution in this instance is regular supplementation with tablets or injections.

Another cause of vitamin B12 deficiency is the impaired absorption of this vitamin from the bowels. Vitamin B12 is absorbed from the latter parts of the small intestine. In the event of a malabsorption syndrome, the body cannot absorb vitamin B12 from food in the gut. There are a number of causes of malabsorption syndromes and symptoms like abdominal pain, bloating, chronic diarrhoea and a loss of weight should alert you to a possible malabsorption syndrome.

Vitamin B12 Supplements

Supplements of vitamin B12 are widely available in tablet, capsule and liquid form. However, evidence suggest that the body only absorbs some 10mcg of vitamin B12 from a 500mcg supplement. Foods containing vitamin B12 are therefore the best source. For vegans who do not wish to use supplements, vitamin B12 can be sourced from many breakfast cereals which have been fortified with this vitamin.

Many vegans opt to take brewer’s yeast for a vitamin B12 deficiency. This supplement is made from the fungus Saccharomyces cerevisiae, and contains many vitamins and minerals, including some of the B-vitamins but vitamin B12 is not present in brewer’s yeast.

Vitamin B12 Injections

Parenteral administration of vitamin B12 in the form of cyanocobalamin and hydroxocobalamin is the better option as there is no concern about diminished absorption from the gut. These precursors of vitamin B12 are readily converted into cobalamin within the body.

Intramuscular injections of vitamin B12 are used to treat pernicious anemia or if there is a deficiency. Another common trend is to have vitamin B12 injections during times of stress, for example students who are studying for exams, but there is no significant evidence to suggest that supplementation at this point is of significant benefit unless there is a vitamin B12 deficiency.

The signs and symptoms associated with a vitamin B12 deficiency are non-specific and may be related to other medical conditions or vitamin deficiencies. It is advisable to speak to a doctor and have a blood test to confirm a vitamin B12 deficiency rather than starting up on supplements unnecessarily.