Vitamin B12

Vitamin B12, found only in foods of animal origin, is unique among vitamins as it contains the metal ion cobalt. For this reason compounds having vitamin B12 activity are called ‘cobalamin’.

In the human body, the vitamin B12 forms ‘methylcobalamin’ and ‘5-deoxyadenosyl cobalamin’ are used. Most supplements contain the form ‘cyanocobalamin’, which is converted in the body (1).

Health functions

Vitamin B12 (cobalamin) contributes to normal red blood cell formation, the immune system, heart health, and neurological and psychological functions.

Disease risk reduction

Even slightly raised levels of the amino acid homocysteine in the blood can result in an increased risk of cardiovascular diseases, as shown in over 80 studies (3).

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Things to know about Vitamin B12

  • Other applications

    Pernicious anemia occurs when stomach cells are not able to produce a certain protein (‘intrinsic factor’), needed by the body to absorb vitamin B12. Symptoms include weakness, pale skin, diarrhea, weight loss, fever, numbness or a tingling sensation in the hands and feet, loss of balance, confusion, memory loss, and irritability.

  • Intake recommendations

    The recommended dietary allowance (RDA) of vitamin B12 (cobalamin) is dependent on age, gender, and other factors.

  • Supply situation

    Detailed intake data on vitamin B12 in European countries are scarce.

  • Deficiency

    Symptoms of vitamin B12 deficiency (or cobalamin deficiency) include numbness and tingling, difficulty walking, memory loss, disorientation, and dementia.

  • Sources

    Foods high in vitamin B12 (cobalamin) include mostly animal products like meat, poultry, fish, and shellfish, and to a lesser extent milk.

  • Safety

    No toxic or adverse effects have been associated with large intakes of vitamin B12 from food or supplements in healthy people.

  • References

    Consult the full list of scientific references.