Vitamin B12 deficiency - symptoms and therapy

Vitamin B12 deficiency - symptoms and therapy

We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.

What do we need vitamin B12 for and what are the consequences of a deficiency?

Vitamin B12 (cobalamin) is a vital, water-soluble vitamin that the human body cannot manufacture itself. So he is dependent on constant intake via food.

The three forms

The vitamin works in three forms in the human body:

  • Methylcobalamin works in the cell plasma,
  • Adenosylcobalamin in the mitochondria (power plants of the cells),
  • and hydroxocobalamin works in both blood and cell plasma.

Methylcobalamin and adenosylcobalamin are both so-called "bioactive coenzymes". The body can only utilize the vitamin directly in these two forms. The third in the league, the hydroxocobalamin is not a coenzyme, but primarily as a toxin and radical scavenger.


Vitamin B12 has the most diverse tasks in the human organism. Cobalamin is involved in energy metabolism, blood formation, DNA synthesis, folic acid metabolism, the breakdown of homocysteine, the production of the myelin sheath (nerve sheath; isolates the nerve fibers) and some neurotransmitters.

Cell division, blood formation, DNA synthesis

The best known is probably the effect of vitamin B12 on blood formation. A pronounced deficiency can lead to anemia. Cobalamin is just as important for cell division to work properly. Folic acid is also involved in this process. If there is a deficiency, so-called transcription errors can occur during DNA synthesis, which in the long term can possibly lead to an increased risk of cancer. Chronic diseases are also associated with it.

The formation of red blood cells, also called erythropoiesis, depends on the presence of the vitamin. Otherwise, this can lead to a maturation disorder of the red blood cells. They are then unable to absorb the required amount of oxygen. Symptoms such as weakness, dizziness, shortness of breath and hypotension indicate this.

Energy metabolism

Advertising tells us that a deficiency can lead to lack of energy. This B vitamin has an impact on performance and energy levels. Our organism needs energy for everything it does. Food is important for this. The energy obtained from this is stored and called up when required. Vitamin B12 plays a major role in this complicated process.

Structure of the cell membrane

Vitamin B12 is involved in the formation of cell membrane lipids. However, this process has not been thoroughly researched. However, the membrane-forming lipids are a component of the myelin sheaths. These act like a protective cover around the nerves, comparable to the insulating layer of electrical cables. If these protective shells are missing, which can result from a vitamin B12 deficiency, those affected suffer from tingling, muscle weakness, paralysis, coordination disorders or memory disorders. In return, it should also have a regenerating effect on nerves.

Nitrosative stress

Nitrosative stress is a kind of oxidative stress. However, it is not the oxygen radicals that are bad here, but the nitrogen monoxide radicals (NO). Too many of them strain the body and can damage it. Nitrosative stress arises from inflammation, chemicals, medication, nicotine, psychological and physical stress. In normal, balanced amounts, NO is important. For example, this relaxes the inner walls of the vessels, which has a positive effect on high blood pressure. Vitamin B12, in the form of hydroxocobalamin, can assert itself against too many nitrogen monoxide radicals and makes NO harmless. It is used to combat so-called nitrosative stress.


Homocysteine ​​is formed during the metabolism of proteins when the essential amino acid methionine is broken down (from proteins in food). Homocysteine ​​is oxidized in the blood and thereby attacks the inside of the blood vessels, which can lead to hardening of the arteries over time and later to a heart attack. Vitamin B6, B12 and folic acid can break down the dangerous homocysteine.

Synthesis of neurotransmitters

Neurotransmitters are messenger substances that are used for the transmission of nerve impulses. It is essential for the synthesis of various messenger substances such as serotonin, dopamine, adrenaline, noradrenaline and acetylcholine.

What cobalamin can do

Cobalamin provides enough energy and thus works against fatigue. The vitamin supports the growth of the nerves, is involved in the production of erythrocytes, ensures healthy cell division, protects the vessels, is important for concentration, good memory and mental energy and has a positive effect on our mood. In addition to folic acid, the presence of vitamin B12 is essential for pregnant women and for successful conception.

Interplay of vitamin B12 and folic acid

Vitamin B12 and folic acid (also called folate or vitamin B9) work closely together in the body. As already mentioned, the two are heavily involved in the breakdown of the harmful homocysteine. Cobalamin is needed to activate folate (this is the natural, bioactive form of folic acid). This means that a functional folate deficiency can develop from a vitamin B12 deficiency.

The vitamin in food

The folate from food is bound in the human organism in the stomach to the so-called intrinsic factor. This is transported into the terminal ileum (last section of the small intestine), where the cobalamin is then released into the bloodstream.

Causes: What can interfere with the absorption of vitamin B12

The causes of a disturbed intake of vitamin B12 include inflammation of the stomach, removal of parts of the stomach, a so-called TYPE A gastritis (an autoimmune disease in which the body attacks its own stomach and therefore the intrinsic factor is no longer properly formed ), atrophic gastritis (atrophic changes in the mucous membrane, decrease in enzyme and hydrochloric acid production), medication (e.g. gastric acid blockers) and chronic intestinal inflammation or removal of intestinal sections.

The vitamin B12 deficiency

In addition to the causes mentioned above, which can be the reason for a vitamin B12 deficiency, there are others. This includes:

  • insufficient intake with food, for example due to a strict vegetarian or vegan diet;
  • malabsorption in which the vitamin cannot even be absorbed by the intestine, as is the case for example with celiac disease and also exocrine pancreatic insufficiency;
  • heavy alcohol consumption,
  • an infestation with the fish tapeworm,
  • improper colonization of the intestine,
  • an increased need (for example as part of an infection or during pregnancy),
  • Displacement by B12 analogues (e.g. Spirulina),
  • old age
  • or the genetic “Imerslund-Gräsbeck syndrome”.

Symptoms of vitamin deficiency

The liver can store folate for up to three years. Therefore, symptoms of vitamin deficiency usually only appear after a few years of persistent undersupply. This includes, above all, tiredness, exhaustion and pallor caused by pernicious anemia (vitamin B12 deficiency anemia).

The lack also affects nerve activity. This causes symptoms such as hand and foot discomfort, tingling, paralysis and waning mental abilities. A well-known sign of the deficiency situation is a smooth red tongue, together with tongue burning and injuries to the oral mucosa. Other symptoms include defensive weakness, tendency to bleed, loss of appetite and weight loss.

Daily consumption - B12 in food

The daily consumption of an adult in vitamin B12 is about 4 µg (micrograms) according to the German Nutrition Society, for pregnant women the value is 4.5 and for lactating women 5.5 µg. Approximately 2000 to 4000 µg are stored especially in the human liver. In the event of an undersupply, this is reduced first.

Vitamin B12 is almost exclusively contained in animal products such as meat, sausages, fish, dairy products and eggs. Exceptions of non-animal origin, with a very low concentration are sauerkraut, sea buckthorn and shitake. For example, 100 g Emmentaler, 70 g beef, 100 g salmon or 60 g minced meat are sufficient for daily needs. It is already clear here that strict vegetarians and especially vegans can develop a vitamin B12 deficiency.

How a deficiency is found

The symptoms listed above usually lead to a doctor. Based on a detailed medical history, the doctor will order a blood test and a urine test. The diet is discussed, possibly reconsidered and changed.

A nutritional deficiency must be distinguished from an absorption deficiency. This requires a special examination. Basically, determining the cause for later treatment is important. For example, a parenteral supply in the form of syringes or infusions may be necessary. This initially replenishes the body in high doses. This is followed by maintenance therapy, often in the form of tablets. A less serious deficiency can also be compensated for by oral substitution.

The type of cobalamin contained in the tablets is important for oral therapy. Preparations containing methylcobalamin, hydroxocobalamin and adenosylcobalamin are recommended. These three types also occur in natural foods and are needed in the body for different tasks.


Folate is an essential, vital vitamin and belongs to the B vitamins, which are primarily responsible for the nerves, brain and fitness. A deficiency can cause fairly far-reaching complaints and must be treated or remedied. A diagnosis of the underlying disease is essential here. People who live strictly vegetarian or vegan for a long time run the risk of developing such a cobalamin deficiency. A daily substitution with a suitable preparation may be considered here.

Scientific studies have also shown that there is a connection between Helicobacter pylori and a lack of vitamin B12. Helicobacter pylori was also found in the stomach in more than half of people with vitamin B12 deficiency. After treatment for Helicobacter infection, the vitamin B12 level in the serum also increased in 40 percent of the patients. B12 malabsorption as a result of Helicobacter pylori infections should be considered here as a possible trigger for vitamin B12 deficiency and hyperhomocysteinemia.

Author and source information

This text corresponds to the specifications of the medical literature, medical guidelines and current studies and has been checked by medical doctors.

Susanne Waschke, Dr. med. Andreas Schilling


  • German Nutrition Society V., reference values ​​vitamin B12, (accessed June 25, 2019), DGE
  • Hans Konrad Biesalski, Stephan Bischoff, Matthias Pirlich et al., Nutritional Medicine, According to the nutritional medicine curriculum of the German Medical Association and the DGE, Thieme Verlag, 4th edition, 2010
  • Larry E. Johnson, Nutritional Disorders - Vitamin Deficiency, Addiction, and Intoxication - Vitamin B12, MSD Manual, (accessed June 25, 2019), MSD
  • Uwe Gröber: Medicines and micronutrients: medication-based supplementation, Wissenschaftliche Verlagsgesellschaft Stuttgart, 4th edition, 2018
  • Bruce H.R. Wolffenbuttel, M. Rebecca Heiner Fokkema, Hanneke J.C.M. Wouters, Melanie M. van der Klauw: The Many Faces of Cobalamin (Vitamin B12) Deficiency, Mayo Clinic Proceedings: Innovations, Quality & Outcomes, (available on June 25, 2019), MAYO
  • Herrmann, Wolfgang; Obeid, Rima: Causes and early diagnosis of vitamin B12 deficiency, Ärzteblatt 2008; 105 (40): 680-5,
  • Serin, E. et al .: Impact of Helicobacter pylori on the development of vitamin B12 deficiency in the absence of gastric atrophy. Helicobacter 2002; 7: 337-41. MEDLINE, NCBI

ICD codes for this disease: E56ICD codes are internationally valid encodings for medical diagnoses. You can find yourself e.g. in doctor's letters or on disability certificates.

Video: 5 Signs and Symptoms of Vitamin B12 Deficiency (July 2022).


  1. Jesus

    all on one and is infinite as well

  2. Arregaithel

    I confirm. All of the above is true. Let's discuss this issue. Here or at PM.

  3. Sewald

    It is remarkable, very amusing piece

Write a message