Vitamin B12 is one of the water-soluble vitamins and has many functions in the human body.

It is involved in the formation of red blood cells, is a component of some enzymes, but also plays an important role in energy metabolism and is important for a well-functioning nervous system.

The European Food Safety Authority (EFSA) has scientifically examined and confirmed the functions of vitamin B12 in the human body. [1] 

• is important for normal energy metabolism
• contributes to the normal functioning of the nervous system
• supports normal homocysteine metabolism
• contributes to normal psychological function
• is important for the normal functioning of the immune system
• is involved in the normal formation of red blood cells
• helps reduce tiredness and premature fatigue
• has a function in cell division

Vitamin B12 intake through the digestive tract can be severely restricted in people suffering from gastrointestinal problems. This is always the case when gastric acid production is restricted, e.g. due to chronic inflammation of the stomach lining or due to stress.

Or when part of the stomach has been removed by surgery. This means that there is not enough gastric acid available to release vitamin B12 from the diet.

Sometimes people over 50 are also advised to take vitamin B12 lozenges, as gastric acid is often not produced in sufficient quantities from this age. As a result, vitamin B12 cannot be removed from the diet and a deficiency can occur.

In a small part of the population, gastric juice lacks the intrinsic factor due to an autoimmune disease, which is formed by certain cells of the gastric mucosa. However, this is necessary so that vitamin B12 can be introduced into the body via the intestinal cells.

• with increased vitamin B12 requirements
• for vegetarians with restricted vitamin B12 intake through food
• for vegans to compensate for the lack of vitamin B12 sources in the diet
• for problems with the stomach and intestines
• during pregnancy and lactation
• with increased homocysteine levels
• for older people whose vitamin B12 intake is restricted
• with increased alcohol and tobacco consumption

Vitamin B12 is one of the water-soluble vitamins and is very safe. The body uses the amount needed individually at a certain point in time and excretes the rest in the urine. Vitamin B12 has no side effects even in very high doses.

The currently recommended daily requirement of 2.5 µg is the amount that humans need in order not to get any deficiency symptoms. This does not mean that the daily requirement is an upper limit.

Rather, it is an approximate minimum amount that the majority of the population needs in order not to become deficient. In fact, the need can vary greatly depending on lifestyle, age, and diet

Therefore, orthomolecular doctors recommend much higher amounts than the recommended daily requirement, if not only to compensate for a deficiency but also to boost a person's vitality and energy by taking vitamin B12. The most recommended dosage is 1000 µg a day.