Vitamin B₁₂

Vitamin B₁₂ (also called Cobalamin) is, like folic acid, a water-soluble B-vitamin. This vitamin exists in different forms, the naturally occurring methylcobalamin, adenosylcobalamin and hydroxycobalamin as well as the synthetic cyanocobalamin.

Clinical studies have shown that all forms of vitamin B₁₂ improve the vitamin B₁₂ levels.

Sources

The main sources of vitamin B₁₂ are of animal origin: fish, meat, liver and to a small extent in dairy products and eggs.

For all those on a vegetarian/vegan diet or who eat little meat, the supply with this vitamin may prove to be difficult.

Bioavailability

The bioavailability of vitamin B₁₂ in humans with normal gastrointestinal function is estimated to be 50% depending on the nutritional source.

Properties

The water-soluble vitamin B₉ is extremely light sensitive.
Vitamin B₁₂, which is bound to protein in food, is released by the activity of the gastric juices in the digestive system and is  mainly absorbed in the small intestine. Vitamin B₁₂ can be metabolized in the liver and in kidneys.

Functions

Vitamin B₁₂, together with folic acid, plays an important role in DNA synthesis, as well as for proper blood cell formation and neurological function. Therefore, it is important during pregnancy to support the growth of the developing fetus.

Furthermore, vitamin B₁₂ in combination with folic acid regulates the homocysteine level in the blood (homocysteine is a naturally occurring amino acid that is associated with cardiovascular diseases at high concentrations in the blood).

It is known that both vitamins, B₁₂ and folic acid, should work “hand in hand” and be available to the organism in sufficient amounts, especially before conception.

Vitamin ₁₂ deficiency is common and increases with age (e.g. due to increased atrophic gastritis or pernicious anemia).

For pregnant women who are vegans or vegetarians and women with pernicious anemia or malabsorption syndromes such as Crohn’s disease or celiac disease, the greatest risk of deficiency is considered.

What is pernicious anaemia?

Pernicious anemia is an autoimmune disease that affects the gastric mucosa, resulting in no intrinsic factor being produced, resulting in vitamin B₁₂ malabsorption. If left untreated, it causes vitamin B₁₂ deficiency.

Consequences of a vitamin B₁₂ deficiency

A vitamin B₁₂ deficiency includes neurological changes, chronic fatigue, megaloblastic anemia, digestive disorders and cardiovascular diseases.

Deficiency in pregnant women is associated with placenta-related complications such as preeclampsia and foetal growth restriction, neural tube defects (NTDs), increased risk of premature delivery, as well as postnatal depression.

Recommendations

Several studies have shown that:

• Vitamin B₁₂ is needed for fertility in men and women.
• an adequate intake of vitamin B₁₂ and folic acid before and during pregnancy was associated with a reduced risk of NTDs, as well as other related disease that mainly occur in the first trimester.

The current recommendations for daily vitamin B₁₂ supplementation during pregnancy and lactation are in the range around 3 µg. However, scientists insist that these intake recommendations be re-evaluated. The German Federal Institute of Risk Assessment (BfR) has recently increased the highest vitamin B₁₂ concentration to be used in dietary supplements from 9 µg (2004) to 25 µg (2018).