Vitamin B12

A vitamin B12 deficiency can occur in vegans, vegetarians and omnivores (from the age of 50). Vitamin B12 is an essential substance for our body as it plays a role in many points. Therefore, a deficiency can have serious consequences. In this blog post you will learn the most important facts about vitamin B12 and what you can do to prevent a deficiency.

Functions

Vitamin B12 plays a role in blood formation, in the production of genetic material, in the breakdown of homocysteine to methionine – together with folic acid – in energy metabolism in the mitochondria, in the nervous system, in the production of messenger substances such as serotonin and in lipid metabolism in the building and maintenance of the cell membrane. Accordingly, a deficiency manifests itself in the following symptoms.

Mild deficiency symptoms

The body store empties. Tiredness, susceptibility to infections, mood swings.

Severe deficiency symptoms

The body stores are exhausted. Depression, dementia, numbness in the limbs, tingling, anaemia, nerve pain, paralysis, coordination disorders. In the long term, this leads to irreversible damage, i.e. it cannot be reversed.

Metabolism

Vitamin B12 is detached from the protein during digestion and bound to IF (intrinsic factor) in the intestine, this is produced in the stomach. B12 can only be actively absorbed through the intestinal wall as a complex with the IF. Therefore, people who can no longer produce IF can suffer from a B12 deficiency. Passively, 1-2 % of the vitamin can also be absorbed in the mouth and intestine. Vitamin B12 is water-soluble; excess B12 is excreted by the kidneys. The total body store is 2-3 grams and 50% each is stored in the liver and muscles. A maximum of 2 µg of vitamin B12 can be actively absorbed per meal. For non-pregnant or breastfeeding people over 13 years of age, a daily amount of 4 µg B12 is recommended.

Vitamin B12 and folic acid

A vitamin B12 deficiency has the same symptoms as a folate deficiency, so it can be misdiagnosed. At the same time, a corrected folate deficiency covers up a vitamin B12 deficiency. This means that it becomes invisible. This can be a problem for vegans, because they have high folate levels. A vitamin B12 deficiency can therefore remain undetected. Therefore, precautionary supplementation is recommended.

Supplementation

Vitamin B12 is produced exclusively by bacteria. The occurrence in plants is too low or in an inactive form, so supplementation is necessary for vegans. Supplementation is beneficial for vegetarians, as dairy products and eggs usually contain too little vitamin B12. Mixed-food eaters should check their vitamin B12 levels regularly from the age of 50, as absorption disorders can occur with age. This can also be the case due to certain medications or diseases. Vegans should check their status regularly (every 1-2 years). Supplements are available as methylcobalamin, adenosylcobalamin, hydroxocobalamin (coenzyme forms) or cyanocobalamin. Cyanocobalamin is unsuitable for smokers. Preparations with at least 250 µg (cyanocobalamin) or 500 µg (coenzyme forms) – or twice as much in the case of absorption disorders – are recommended because they take active and passive absorption into account. In general, one should supplement as much as necessary but as little as possible. Depending on the absorption, a dose of 250 µg 2 to 3 times a week is sufficient. Since the superfluous vitamin B12 is excreted again, some nutritionists (for example Niko Rittenau) recommend a daily dose of 250 µg.

Diagnostics

Although the holo-transcobalamin value is the most accurate, testing 2 or more parameters is recommended for reliable diagnosis. The optimal value of holo-transcobalamin is > 50 pmol/l.