Vitamin B12 (cobalamin)

The most commonly used forms of vitamin B12 in preparations are hydroxycobalamin and methylcobalamin. A protein (intrinsic factor) formed in the gastric mucosa is necessary for vitamin B12 absorption. Our body stores vitamin B12, with 50-90% of it being stored in the liver.

The functions of the vitamin in the body

Blood formation
Vitamin B12 is involved in the formation of red blood cells (erythrocytes) in the bone marrow and also ensures the incorporation of iron into erythrocytes.

Folic acid metabolism 
Vitamin B12 is necessary for the conversion of folic acid into its active form.

Mitochondrial metabolism 
Vitamin B12 is an extremely important co-factor in the metabolism of mitochondria (this is where energy production takes place in the cell).

Nerve cells 
Vitamin B12 is needed for the synthesis of myelin, the protective layer for many peripheral nerve cords of the spinal cord and brain.

Cell development 
Together with folic acid, vitamin B12 is necessary for the formation of building blocks for DNA (deoxyribonucleic acids = our genetic material).

Good to know about vitamin B12

  • The daily requirement of vitamin B12 is 3-4 µg for men and women alike.
  • If the intrinsic factor (a protein formed in the human stomach for optimal absorption of vitamin B12 in the intestine) cannot be formed in sufficient quantities, vitamin B12 must either be taken orally or administered separately as an injection once a week.
  • Vitamin B12 deficiency can be easily detected by a blood test at the doctor's office.
  • Vitamin B12 is heat-sensitive, therefore considerable amounts can be lost during food preparation.

Can vitamin B12 be overdosed?

At high doses, half of the first 5 µg (i.e., about 2.5 µg) is actively absorbed by intestinal cells via intrinsic factor - of the remainder, about 1% enters the body via passive diffusion from the intestine.

Even in the case of intake of high doses of over 10 mg per day, there are no reports of toxic reactions in healthy adults.

Vitamin B12 deficiency - the symptoms

  • blind spots and decreased vision
  • smell and taste disorders
  • impaired concentration
  • poor coordination of the muscles
  • weakness and shortness of breath
  • weak immune system
  • disturbances of the blood count
  • numbness and tingling in hands and feet
  • loss of the sense of touch

Vitamin B12 in food per 100 g

veal liver   60 µg   salmon   3 µg
beef, fillet     2 µg   "emmental" cheese      2 µg
chicken egg (medium)       1 µg               


Produkte mit Vitamin B12...