Anemia due to Vitamin B12 Deficiency

Meanings of Anemia due to Vitamin B12 Deficiency

A anemia (anemia) due to vitamin B12 deficiency featuring a decreased hemoglobin content in the serum, which is due in most cases to malabsorption of vitamin B12 in the gastrointestinal tract. Older people in particular often suffer from a vitamin B12 deficiency and are at risk of vitamin deficiency anemia.

What is vitamin B12 deficiency anemia?

According to, anemia due to vitamin B12 deficiency is a deficiency in hemoglobin, the red blood pigment of the erythrocytes (red blood cells), which is essential for the transport of oxygen, due to a lack of vitamin B12.

Vitamin B12 is an essential component for the synthesis of chromosomes (genetic material of cells). During cell division, a cell’s chromosomes have to be doubled. If there is a deficiency in vitamin B12, the cell division process is disturbed, so that cell division and maturation of those cells in the bone marrow from which the erythrocytes are formed is also slowed down.

The proportion of red blood cells in the serum is correspondingly reduced and, in the long term, anemia results from a vitamin B12 deficiency. If left untreated, anemia slowly leads to frequent feelings of weakness and fatigue, shortness of breath during exertion, palpitations, increased pulse, neurological symptoms, as well as poor concentration and pale skin.


Anemia due to a vitamin B12 deficiency is in most cases due to impaired processing or absorption of the vitamin in the small intestine. Vitamin B12 can only be absorbed in the small intestine if it forms a complex with a certain protein molecule formed by the parietal cells of the gastric mucosa, the so-called “intrinsic factor”.

If this intrinsic factor is missing, for example as a result of pernicious anemia, an autoimmune disease in which the body’s own antibodies are directed against the parietal cells of the gastric mucosa, the vitamin cannot be absorbed and anemia due to vitamin B12 deficiency occurs.

In addition, infections with intestinal parasites (including fish tapeworm), which lead to an increased need for vitamin B12, intestinal diseases such as Crohn’s disease and partial removal of the small intestine or stomach can lead to anemia. In contrast, anemia caused by vitamin B12 deficiency, apart from a vegan diet, is rarely caused by malnutrition.

Symptoms, ailments & signs

Anemia caused by vitamin B12 deficiency is a very serious disease which, if left untreated, is very often fatal. The so-called vitamin B12 deficiency anemia or pernicious anemia is characterized by many different symptoms. Typical symptoms that can be attributed to the lack of blood are chronic fatigue, severe drop in performance, increased heart rate, pale skin and a tendency to collapse.

The red blood cells are larger than normal but fewer in number. In addition to these symptoms, there is often a burning tongue, canker sores on the tongue and oral mucosa, angular angular disease and indigestion. Infants and young children often suffer from severe developmental disorders. In infants, a vitamin B12 deficiency manifests itself through frequent crying (crying baby).

In addition, stomach pains occur as a result of the autoimmune gastritis causing the vitamin B12 deficiency. In addition, the anemia of a vitamin B12 deficiency is also accompanied by neurological symptoms. Neuropathies occur that are characterized by tingling, abnormal sensations, numbness of the skin, hands and feet that have fallen asleep, coordination disorders and unsteady gait.

In extreme cases, severe paralysis and severe pain can also occur. The affected people are generally very sensitive to pain anyway. The nerve damage becomes irreversible if the treatment is not given in time. Furthermore, psychological symptoms such as depression, poor memory, concentration disorders, dementia, psychoses or schizophrenia can occur. It is also believed that patients with vitamin B12 deficiency anemia are at increased risk for cardiovascular disease and cancer.

Diagnosis & course

Anemia due to vitamin B12 deficiency is diagnosed using a blood test. A decreased vitamin B12 content in the blood serum, decreased reticulocyte values ​​(precursor of erythrocytes) and enlarged erythrocytes with an increased hemoglobin content indicate anemia.

Further examinations are also used for differential diagnostics. With the help of the Schilling test, the impaired absorption of vitamin B12 can be determined. Any parasite infestation can be detected as part of a stool analysis. If the anemia is caused by pernicious anemia, the antibodies against the parietal cells of the gastric mucosa can be determined, while a gastroscopy provides information about the characteristic impairments.

The course and prognosis of anemia due to vitamin B12 deficiency depend heavily on the underlying cause. If left untreated, anemia leads to neurological damage that is often irreversible.


Without treatment, the anemia caused by a vitamin B12 deficiency can lead to cardiovascular complications: In the long term, increased stress on the heart is possible. The reduced oxygen transport also increases the risk of cardiovascular collapse. The latter can lead to further complications – for example from falls, which may result in injuries.

The lack of vitamin B12 can in itself also cause complications. Permanent neurological disorders are also possible without treatment. A sufficient compensation of the deficiency should therefore take place as early as possible. In the case of a vitamin B12 deficiency, neurological complaints manifest themselves, for example, as a numb feeling or tingling sensation in the arms or legs.

In addition to the general symptoms of anemia, other signs may appear with vitamin B12 anemia. These include tiredness, paleness, indigestion, feeling weak, bleeding gums and drowsiness. In addition, the speed of your heartbeat and breathing may increase.

Psychological complications include memory impairment, confusion, difficulty concentrating and depressive mood. In some cases, psychotic perceptions in the form of hallucinations, flight of thoughts or similar symptoms are also possible. In addition, a severe deficiency in vitamin B12 can lead to personality changes.

Concentration and memory problems in particular can lead to a deterioration in professional or school performance. Overall, the various symptoms may also contribute to the affected person withdrawing socially.

When should you go to the doctor?

Parasitic sensations such as feelings of coldness in the feet and hands are common side effects of a VB12 deficiency. Permanent tickling on the surface of the skin, constant impaired concentration and excessive daytime tiredness also occur with prolonged undersupply. These early warning signs are a sufficient reason to consult the family doctor. The anemia itself is considered to be a long-term consequence of a deficiency condition.

The mere suspicion in combination with pale skin, poor performance and dizziness justifies a closer examination of the vitamin B12 level. Anemia also causes a massive deterioration in the general condition of existing diseases due to the low oxygen supply in the bloodstream.

Permanent inflammation of the gastric mucosa greatly reduces the ability of the gastrointestinal tract to absorb vitamin B12. In the case of regularly recurring abdominal pain, it is therefore advisable to check the vitamin B12 supply. Those affected often perceive the decline in their performance as a creeping process. Even sufficient rest often does not bring any fundamental improvement.

Occasional tiredness without a continuous drop in fitness is usually not due to a fall below the VB12 value. Distinctive features such as inexplicable increased heart rate, a red colored tongue, nervous behavior, neurological symptoms and signs of jaundice also provide important clues. Due to the numerous causes of anemia, a specific analysis of the background can only be carried out using the blood serum. We urgently advise against postponing a medical evaluation. If left untreated, anemia causes potentially life-threatening conditions.

Treatment & Therapy

In the case of anemia due to a vitamin B12 deficiency, the therapeutic measures always aim to eliminate the underlying disease and the vitamin deficiency through substitution therapy with synthetic vitamin B12.

To do this, artificial vitamin B12 (1000 µg) must be injected into the muscle every week for the first three weeks at the start of therapy. The affected person is then injected intramuscularly with the same amount of vitamin B12 every 1 to 3 months. In addition, there is initially an increased need for iron to regenerate red blood cells (erythrocytes), which should be covered by additional iron supplements.

If there is an underlying disease such as pernicious anemia that cannot be cured, or if the stomach or parts of the small intestine have been surgically removed, synthetic vitamin B12 must be injected for life in most cases in order to prevent anemia caused by a vitamin B12 deficiency.

In rare cases (around two to five percent of those affected) late complications such as gastric or rectal cancer can occur. For this reason, annual gastroscopies should be carried out as a check-up even after successful completion of treatment for anemia.

Outlook & forecast

The prognosis for anemia due to vitamin B12 deficiency depends on the cause of the vitamin B12 deficiency. Usually there is inflammation of the gastric mucosa, which is caused by autoimmune reactions of the immune system against the parietal cells of the stomach. The parietal cells of the stomach are destroyed.

In this case it is a so-called pernicious anemia, which cannot be cured. The parietal cells form the so-called intrinsic factor, which is responsible for the absorption of vitamin B12 in the intestine. Because of this autoimmune disease, the body can no longer absorb vitamin B12. Vitamin B12 must therefore either be administered in large quantities or injected.

Without vitamin B12, the prognosis for pernicious anemia is very poor. Fatigue, poor concentration and poor performance are increasing. At the same time, there is also an increasing number of neurological failures. If left untreated, pernicious anemia ultimately leads to death.

In rarer cases, however, a vitamin B12 deficiency has other causes. This applies, among other things, to strict vegetarian diets, parasite infestation in the intestine, stomach reductions, bacterial contamination of the intestine, after intestinal operations or malabsorption syndrome.

In these cases, the appropriate treatment takes place after the cause of the vitamin B12 deficiency has been determined. After eliminating the cause, such as worm infestation, the body can again be supplied with sufficient vitamin B12, which stimulates blood formation.


There are some measures that can prevent anemia caused by a vitamin B12 deficiency. This includes a varied diet, especially for people who follow a vegan diet. In addition, people who have had bowel surgery or who have chronic inflammation of the gastrointestinal tract should have regular checkups for anemia.


Serious anemia always belongs in the hands of an experienced doctor. Anemia caused by vitamin B12 deficiency is classified as the most severe form of anemia caused by vitamin B12. Because megaloblastic or pernicious anemia can be fatal without treatment, prompt treatment and lifelong follow-up are essential.

As a first measure, the cause of the vitamin B12 deficiency must be determined. As such, the stores of this vitamin are filled for a relatively long time, but absorption disorders or the consequences of operations can have a negative impact. Following the diagnostic phase, a permanent supply of vitamin B12 must be ensured.

The blood values ​​must then be checked in regularly scheduled follow-up examinations. Follow-up care must be maintained for life, as the causes of the dramatic vitamin B12 deficiency can usually not be remedied.

After the acute treatment of anemia, maintenance therapy with vitamin B12 is initiated. This measure must be monitored regularly. If the vitamin is administered by injections, a follow-up examination must be carried out at least every two months. If you take high-dose vitamin B12 tablets with at least 5000 ug, regular follow-up appointments should also be made.

Follow-up care is particularly important because a recurring vitamin B12 deficiency can endanger the patient’s life. Follow-up ensures that the blood count returns to normal. However, a cure is not possible.

You can do that yourself

The easiest way to compensate for anemia caused by a vitamin B12 deficiency is to change your diet. Those affected can compensate for the deficiency primarily by consuming animal products such as meat, eggs or offal. Fermented foods such as sauerkraut or beer also contain the B vitamin and quickly counteract mild anemia. In the case of severe anemia, dietary supplements containing vitamin B12, folic acid and iron can also be used.

Bed rest is recommended for those who suffer from anemia after an operation or parasitic disease. At the same time, the deficiency can be counteracted with meat broth and drinking a lot. A nutrition plan helps to regulate the vitamin B12 intake and prevent re-anemia.

Vegetarians and vegans in particular can avoid various symptoms of deficiency through a balanced diet. Women with heavy menstrual bleeding should also take preventive action and compensate for possible vitamin B12 and folic acid loss through a healthy diet and supplementary preparations.

If the symptoms of anemia persist despite all measures, there may be another cause. A doctor should then diagnose the anemia and, if necessary, suggest appropriate therapy.

Anemia due to Vitamin B12 Deficiency

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