Vitamin B12 deficiency


Vitamin B12 is a very important and vital vitamin for the body. It will be far over 100 various processes in the body and is therefore essential for the body to function. Since vitamin B12 is mainly found in animal products A vitamin B12 deficiency is an issue that is included vegetarian and vegan significantly affects. But also various diseases of the Digestive tract, in which the vitamin can no longer be sufficiently removed from the food pulp, play a decisive role. Vitamin B12 (also "Cobalamin"called) in the healthy liver circa 2-3 years saved, and the daily dose of approx 2 micrograms (i.e. 2 millionths of a gram) for this period easily balanced. However, different diseases can lead to a number of symptoms, which are discussed in more detail below.


A Vitamin B12 deficiency brings with it a wide range of symptoms, which can be broadly divided into three categories: Internal medicine Symptoms, Neurological Symptoms and Psychiatric Symptoms.

Internal symptoms

Internistic symptoms are symptoms that affect the internal organs of the body. Since vitamin B12 is required for the formation of red blood cells, what is known as vitamin b12 deficiency anemia, i.e. vitamin B12-related anemia, occurs over time. The shortage of red blood cells causes the remaining blood cells to become “cluttered” with too much hemoglobin and swell. As a result, they are less mobile and can pass the fine, permeable wall layer of the vessels less easily. The swelling of the erythrocytes is medically called macrocytic anemia. Similar to iron deficiency, this manifests itself through exhaustion, listlessness and lack of drive - all unfortunately quite unspecific symptoms, which is why the disease is often not recognized for a long time.

Since, in addition to blood formation, DNA and cell formation also function poorly, immunological symptoms are increasingly coming to the fore, such as the increased occurrence of common diseases such as a cold or increased susceptibility to infections.

Other symptoms can be high blood pressure, allergies, headaches, poor concentration, torn corners of the mouth (so-called fissures) and increased occurrence of canker sores and inflammations on the oral mucosa (please refer: Red spots on the tongue). The latter can be explained by the reduced rate of cell formation that goes hand in hand with a B12 deficiency: the oral mucosa and skin are strongly proliferating, i.e. organs that are constantly being restructured - a cell deficiency is particularly noticeable here.

In advanced, severe stages, the symptoms of B12 deficiency range from heart attack, cerebral infarction, muscle tremors, visual disturbances, incontinence, dizziness and unsteady gait to fainting.

Can a vitamin B12 deficiency lead to diarrhea? You can find out everything about this topic at: Diarrhea from vitamin B12

Neurological symptoms

In addition to the internal symptoms, there are a number of neurological symptoms. This is because vitamin B12 is required for building what is known as the myelin sheath of the nerves. The myelin sheath is the sheathing of the nerves, similar to the rubber layer that insulates power cables. Without this insulating layer, signals can no longer be passed on if at all.

Neurological symptoms often appear before the physical ones: Parasitic sensations with disturbance of the sensation of vibration can occur, which continues in an impairment of the deep sensitivity (symptomatic by "tingling" of the limbs) and in advanced stages can end in paralysis, as well the muscles are supplied by nerves. Furthermore, the risk of developing Alzheimer's dementia and other neurodegenerative diseases is increased.

The symptoms of vitamin B12 deficiency can be masked by an overdose of folic acid.

  • Read more about this at: What happens if I overdose with folic acid?

Psychiatric symptoms

Psychiatric symptoms form a smooth transition to neurological symptoms and manifest themselves in the form of hallucinations, psychoses and confusion. Panic attacks and anxiety can also occur.

Since the vitamin B12 deficiency affects a very elementary level of body function, the possible effects and manifestations are very different. The deeper the disorder, the more varied the symptoms. It is the same with B12 deficiency, which often makes a quick diagnosis and treatment difficult. Often only the combination of several symptoms gives the decisive clue in the right direction.

The symptoms of vitamin B12 deficiency can be masked by an overdose of folic acid.

  • Read more about this at: What happens if I overdose with folic acid?

root cause

Admission disorder

Absorption disorders exist when the vitamin B12 no longer sufficiently absorbed from the digestive tract can be. This may be because parts of the gastrointestinal tract were surgically removed, such as after a Gastric removal, or one Illeum-Distance.

Furthermore, a chronic gastritis, i.e. chronic inflammation of the stomach, prevent absorption of the vitamin. In the stomach are the so-called Parietal cells (parietal cells)that the Intrinsic factor to produce. This is necessary in order to absorb vitamin B12 in the intestine. In gastritis, the formation of this glycoprotein is also disturbed.

Also Medication can cause a B12 deficiency with long-term ingestion: A well-known example is that Proton pump inhibitorswhich are usually taken with pain relievers such as ibuprofen. A representative of the proton pump inhibitors (PPI for short) is Pantoprazole. It reduces the production of hydrochloric acid in the stomach and thus protects the stomach lining. However, when taken continuously, it causes a B12 deficiency. Other drugs that impair absorption are the antidiabetic drug Metformin and those also used to inhibit gastric acid secretion H2 receptor antagonists (amongst other things: Ranitidine). These causes can underlie an absorption disorder.

Lack of admission

A Lack of admission is special at Vegans and vegetarians typical: Since vitamin B12 is almost exclusively through animal food is consumed, a deficiency is to be expected in the long term in people who refrain from meat products. For example, 100 grams of veal liver contains 20 times the amount of vitamin B12 required daily, whereas fruit, vegetables and nuts contain none at all. Hence should avoid a vegan diet during pregnancy to prevent damage from possible vitamin and nutrient deficiencies in the unborn child.

Since vitamin B12 formed by microorganisms in the intestinal wall is can one bacterial overgrowth of the intestine also lead to a decreased absorption. This category also includes excessive Alcohol consumption or alcoholism, in which the intestinal and gastric mucosa are gradually destroyed. But also Fish tapeworm infestation and Celiac disease lead in the long run to an intake deficit.


Very often there is a vitamin B12 deficiency due to excessive Alcohol consumption. The reason is that alcohol often causes a Inflammation of the stomach lining, mostly chronic. This enables the formation of what is necessary for vitamin B12 absorption Intrinsic Factors and as a result, the vitamin cannot be sufficiently absorbed from the food.

For heavy alcoholics there is also one Malnutrition added. So only one-sided and low-vitamin products are often consumed. With a long and chronic deficiency of vitamin B12 it can neurological abnormalities come. These abnormalities are particularly pronounced in strong alcoholics. Vitamin B12 is also always given (usually by injection) to patients who suffer from alcoholic disorders to compensate for these neurological abnormalities.


If left untreated, vitamin B 12 deficiency leads to decreased ability to concentrate, tiredness and weakness.

In the case of long or severe vitamin B12 deficiency, there are initially mild and later also more severe abnormalities.

At first, a slight vitamin B 12 deficiency is not noticed. The stronger it becomes and the more pronounced it is, the more complaints there are. First of all, rhagades at the corners of the mouth (small tears) and inflammatory swelling of the tongue (Glossitis).

With a vitamin B12 deficiency, there is always anemia. In this respect, all symptoms of anemia are present in the case of a severe deficiency. These would be tiredness, concentration disorders, weakness and increased susceptibility to infections.

In the case of severe and long-term deficiency, neurological complaints can also arise. The reason is that vitamin B12 is also involved in the transmission of nerve stimuli. Serious deficiencies can cause unsteady gait and stance, tremors and muscular cramps. Vitamin B12 is also thought to be involved in memory performance. A long or severe deficiency in vitamin B12 could also make itself felt through a disturbance of the memory. In so-called funicular myelosis, there are also abnormal sensations, unsteady gait and memory problems.

Please also read: funicular myelosis


A frequent consequence A vitamin B12 deficiency is also considered a anemia designated Anemia.

For the Blood formation and for the Oxygen loading of the red blood cells a certain concentration of vitamin B12 is necessary and should not fall below it for a long time. If, as a result of a vitamin B12 deficiency, there is a reduced load of the red blood cells with oxygen, the first symptoms arise.

Those affected usually notice one Fatigue and listlessness. Sleep times are extended, waking times can sometimes only be maintained for a few hours a day. Vitamin B12 deficiency also leads to Difficulty concentrating, which then usually become noticeable at the same time. In addition to the indicated symptoms, there is also one due to the lack of oxygen Pallor of the skin, also to peeled off conjunctival areas.

Patients with severe vitamin B12 deficiency anemia usually also experience a gloomy mood in appearance and speak slowly. Prompt treatment should be initiated. After the vitamin B12 deficiency has been compensated for, the general well-being slowly improves. The administration of vitamin B12 should be taken under regular Laboratory controls to be carried out for a few months.


In addition to the clinical symptoms, which are unfortunately relatively unspecific and can also indicate a variety of other diseases, one usually simply measures the Vitamin B12 levels in the blood.

However, a deficiency should not yet be diagnosed on the basis of these 2 parameters: One increased red blood cell volume (Laboratory parameters MCV For Mean Corpuscular Volume) and a decreased erythrocyte count, as well as a increased homocysteine ​​and methylmalonic acid levels are trend-setting in addition.


Any vitamin B12 deficiency should be corrected as soon as possible in order to prevent symptoms and further worsening of the Vitamin B12-To prevent deficiency.

Once the diagnosis has been made, therapy is relatively simple and straightforward. There are various options available to remedy the vitamin B12 deficiency. Before every treatment is first important to find out what the root cause the vitamin B12 deficiency and, above all, how severe the deficiency is.

Therapy in the event of insufficient intake

Is it a minor vitamin B12 deficiency due to a Malnutrition, it is necessary that Change your diet. Foods rich in vitamin B12 include: Whole milk, fish, offal and Red meat. Various Cheeses also have a slightly lower vitamin B12 content.

Vitamin B12 can either orally (taken in by mouth) or intramuscular (injected) can be substituted. As a rule, depending on the severity of the vitamin B12 deficiency, month-long injections in the upper arm muscle for a few months.

Is the Intrinsic factor If you are sufficiently trained and only the amount of vitamin B12 ingested with the food is not sufficient for satiety, a treatment attempt with vitamin B12 tablets can be undertaken. This intake should also be carried out over several months. There are also freely available on the Internet Supplements with vitamin B12that are taken at regular intervals. It should be noted, however, that a Vitamin-B12 substitution (e.g. with Vitasprint) always in combination with folic acid intake (vitamin B9) should be done. The vitamin B12 substitution is particularly useful for vegans or vegetarians who do not ingest the vitamin with their food.

However, you should not start arbitrary vitamin B12 substitution, but always consult your family doctor and only take prescribed B12 supplements as directed.

Therapy for resoption disorders

When changing your diet, it is also important to note that none Resorption disorder present. Because if the vitamin B12 absorption is due to a deficiency of the I.ntrinsic factors is impaired, vitamin-rich foods cannot compensate for the vitamin deficiency. In this case, the vitamin must be considered injection to be consumed. Since you have the Intrinsic factor can not be added artificially, one has to bypass the gastrointestinal tract, in which vitamin B12 is normally absorbed.

In the Substitution therapy the dose that would be given in the event of a lack of intake is not sufficient. If there is a resorption disorder, then simply one is done Dose increase by a thousand times daily needs, from 2-3 micrograms to 2-3 milligrams. As a rule, with such a high availability, enough vitamin B12 can still be absorbed in the body so that the deficiency can be successfully treated. In addition, the patient saves permanent injections into the muscle. A Overdose is hardly possible, by the way, since the body simply uses the appropriate amounts kidney filters, and excretes with the urine.


Prophylaxis is actually not necessary for people with average eating habits because the liver enough vitamin B12 for 2-3 years saves. In the event of a deficiency, it can release the required daily dose bit by bit, so that even years of vegan or vegetarian diets remain without symptoms. The “normal consumer”, who consumes meat several times a month, does not need to take prophylaxis unless there is one Absorption disorder (see above).

Since vitamin B12 in addition to Vitamin B6 and Folic acid the Lowers blood homocysteine ​​concentrationFor a long time it was advised to substitute these vitamins. Homocysteine ​​is considered to be in high concentrations Risk factor for arteriosclerosis and cardiovascular diseases. However, the effectiveness of this therapy has been questioned in several studies and is still not fully understood.

For patients who cannot absorb vitamin B12 well, there is one permanent substitution indicated for prophylaxis. This can be done either orally or intramuscularly if daily substitution is not desired. An increased dose is simply injected into the muscle and stored in the liver for a longer period of time.


With an increasing turn away, especially the younger generation, from consuming animal products and one increasingly vegetarian diet moves next to that Iron deficiency The vitamin B12 deficiency is also increasingly in focus. The problem here is that the first symptoms appear years later and therefore not directly associated with the change in diet. It is therefore particularly important for vegetarians and vegans to find out about the possible effects of not doing so in order to be able to take countermeasures at an early stage.

Vitamin B12 Deficiency in Children

Vitamin B12 deficiency in children is in most cases due to one decreased intake justified by diet.

Of the Intrinsic factor is fully trained in most cases. Exceptions are children with whom there is a diminished or complete lack of training of Intrinsic Factors has come. Here one can hereditary conditional cause be to blame.

It is said that children are complete vegan feed a sufficient Vitamin B12 source is missing. Because the vast majority of vitamin B12 is made up animal sources (red meat and fish and cheese), these vitamin suppliers are missing in the children and must necessarily be supplied artificially. At vegetarian nourished children, the risk is not as high as animal products are consumed (Cheese and milk).

Compensating for a vitamin B12 deficiency is particularly important in children because it is sustainable and irreparable Development damage can result from it. In addition to the well-known arising from a vitamin B12 deficiency fatigue, sometimes severe neurological abnormalities can occur. Severe vitamin B12 deficiency in childhood can also mental retardation arise. Immediate compensation for a vitamin B12 deficiency should therefore be aimed for. A vegan diet in childhood should be avoided.