Vitamin B12 – effect, occurrence, daily requirement & values

Vitamin B12, also known as cobalamin, is a water-soluble vitamin that is essential for various vital functions in the body. Because of its colour – it is also known as the “red vitamin” – B12 was the last of the vitamins known today to be discovered (1926). However, this does not make the water-soluble nutrient less important for us humans.

It plays a central role in cell division and in the functioning of the nervous system and it is indispensable for the formation of blood cells, especially red blood cells.

However, this essential vitamin is found almost exclusively in foods of animal origin such as meat, fish, eggs and dairy products. People who eat vegan foods therefore have an increased risk of developing vitamin B12 deficiency because this nutrient is hardly ever present in plant-based foods. People who eat a lacto-vegetarian diet, i.e. do not eat meat, fish or eggs, also potentially absorb less vitamin B12, especially if dairy products are only on the menu to a very limited degree.

Because of its colour, vitamin B12 is also called the “red vitamin”.

Vitamin B₁₂is an essential vitamin that is involved in blood formation and cell division. It also contributes to normal homocysteine metabolism, to the immune function, to energy metabolism and to normal mental functions.

As already mentioned, vitamin B₁₂ is only found in animal foods in quantities that meet the average person’s needs. What are vitamin B12 rich foods? Foods that are high in vitamin B12 are meat, fish, eggs meat, fish, eggs, offal and dairy products. People who often consume them, can usually meet their daily needs. However, there is usually no vitamin B₁₂ in plant-based foods. Exceptions are fermented foods such as sauerkraut or beer as well as bacterially contaminated foods (e.g. bulb and root vegetables), which can contain various B₁₂ variants in traces. However, under certain circumstances these compounds are present in a form that cannot be used by us (“vitamin B₁₂ analogues”) and can even further hinder the vitamin B₁₂ that we use in its utilisation through their mixing.

In order for our bodies to utilise vitamin B12, it must first be extracted from food. It then binds to a special protein, the intrinsic factor, which is produced in the stomach lining. Only then can vitamin B12 be actively absorbed in the small intestine.

The good news is that in higher doses, e.g. through supplements (vitamin B12 tablets, capsules or drops), the body can also absorb vitamin B12 passively through the intestinal mucosa.

In order to check the vitamin B₁₂ balance, the total vitamin B₁₂ is usually measured in the blood. However, this value only ever indicates a B₁₂ deficiency quite late in the day. Even if the value of the total vitamin B₁₂s is not alarming, there may already be an insufficient supply. Ideally, further values should therefore be used. Holotranscobalamin (Holo-TC), also known as “active B₁₂”, is a laboratory value that indicates B₁₂ deficiency early on. Low Holo-TC values indicate a drainage of the B₁₂ supply or a negative B₁₂ balance. Methylmalonic acid (MMS) values also indicate our B₁₂ status.In this case, increased values indicate empty B₁₂ depots.

Our body doesn’t need much, and according to the DGE (Deutsche Gesellschaft für Ernährung [German Nutrition Society]), 4μg daily is enough to maintain the vitamin B₁₂ balance in the body. One exception – as is often the case – is the special phase of pregnancy and breast-feeding. During this period, the need for B₁₂ increases to 4.5 μg and 5.5 μg daily. Our organism has stores for somewhat "leaner B₁₂ times". If well filled, they accommodate approximately a thousand times the amount (4 g) of the daily B₁₂ requirement. However, a constant shortage in supply can empty the storage tanks over the short or long time.

Vitamin B₁₂and folic acid are team players and work closely together within our metabolism – they contribute to homocysteine metabolism and play a role in blood formation *. In addition, these two-water-soluble B vitamins support the normal functions of our mind.