Vitamin B12 deficiency and skin changes: the most important questions and answers

Vitamin B12 Mangel und Hautveränderungen: Die wichtigsten Fragen und Antworten

Vitamins are seen as indispensable elements of physical as well as mental health. However, not all vitamins get the same attention, although all are very important.

Increased tiredness and listlessness as well as skin changes are often associated with a vitamin B12 deficiency. This article provides detailed information about the essential functions of this vitamin, as well as the causes and consequences of a deficiency.

In addition, the treatment methods to counteract or prevent a vitamin B12 deficiency are discussed.

the essentials in brief

  • Vitamin B12 takes on essential functions to form numerous cells in the body and is therefore called the " cell vitamin ".
  • Vitamin B12 is found almost exclusively in animal foods and is produced by microorganisms.
  • A deficiency is often not recognized until late because the symptoms can be so diverse and unspecific.

Definition: What is vitamin B12?

Vitamin B12 is necessary to form new cells such as red blood cells, skin or nerve cells in the body. That is why it is also called the "cell vitamin".

Vitamin B12 is one of the eight B vitamins. They are completely different from each other in terms of their chemical structure and their effect, but they are all water-soluble vitamins. Vitamin B12 is only made by microorganisms such as bacteria and archaea.

Vitamin B12 is a collective name for different compounds, the so-called cobalamins. However, in addition to the vitamin-effective cobalamins, there are also so-called vitamin B12 analogues. They are found in individual plant foods such as sauerkraut or algae. However, you cannot cover your needs by eating these foods.

Vitamin B12 deficiency and skin changes: What you should know

This section deals with all relevant background information on the subject of vitamin B12.

What is the function of vitamin B12 in the body?

Vitamin B12 is responsible for important metabolic functions and is essential for cell division, blood formation and the normal functioning of the psyche.

  • Cell formation and division: Vitamin B12 is required for the production and regeneration of body cells and therefore plays a role in all growth processes associated with cell division. It is also involved in the formation of human genetic material (DNA).
  • Nerve function: Vitamin B12 is not only important for the production and regeneration of nerve cells, but also for the synthesis of messenger substances (neurotransmitters).
  • Blood formation: Due to its role in cell division, vitamin B12 is also important for the formation and maturation of red blood cells (erythrocytes). A deficiency can lead to anemia.
  • Metabolism of homocysteine: The amino acid homocysteine ​​occurs naturally in the body. However, high levels of homocysteine ​​in the blood can damage the blood vessels and brain. Vitamin B12 helps detoxify homocysteine.
  • Energy metabolism: Vitamin B12 is a so-called coenzyme. This means that it aids in the remodeling and release of metabolites, thereby participating in the promotion of energy from nutrients.

What are the causes of a vitamin B12 deficiency?

In principle, a vitamin B12 deficiency can be attributed to insufficient intake of vitamin B12 through food, insufficient absorption of vitamin B12 in the intestine or increasing vitamin B12 requirements due to pregnancy. (1)

Malabsorption in the gut is more often the trigger for vitamin B12 deficiency than is thought.(2)

Malabsorption can have different causes:

The vitamin B12 bound in proteins has to be released by gastric acid so that it can be used by the body. If the gastric acid production is restricted, for example by taking medication, problems can arise. (3)

In addition, vitamin B12 has to be processed in the small intestine by digestive enzymes (Typsin), which are produced by the pancreas. Therefore, a disease of the pancreas can cause a vitamin B12 deficiency.

Vitamin B12 is absorbed into the blood in the small intestine by a special transport protein. The so-called intrinsic factor is formed by special stomach cells. The absence or depletion of this protein is problematic and can have several causes. (4)

On the one hand, the gastric mucosa changes with age, which means that the body's own production of intrinsic factor decreases. On the other hand, a partial removal of the stomach can also lower the intrinsic factor.

In addition to chronic inflammation of the gastric mucosa, pernicious anemia also affects the production of the intrinsic factor.

This occurs due to an autoimmune disease and leads to chronic gastritis. Your own immune system fights parietal cells in the stomach and the intrinsic factor, which leads to a vitamin B12 deficiency.

In addition, chronic intestinal diseases such as ulcerative colitis, Crohn's disease and celiac disease often lead to a vitamin B12 deficiency. (5)

Some medications, such as acid-blocking drugs or certain diabetes medications, also inhibit vitamin B12 absorption. Other medicines such as gout medicines or medicines for high blood fat levels and epilepsy interact with vitamin B12. (6)

Aside from the causes listed, alcoholism, tumor diseases and AIDS can also cause a vitamin B12 deficiency.

vitamin capsules

People who belong to the risk group should take vitamin supplements. (Image source: Unsplash / Simone van der Koelen)

What are the symptoms of a vitamin B12 deficiency?

In the case of a chronic undersupply, the symptoms are often only noticed after years because it is a gradual process. If left untreated for a long time, severe vitamin B12 deficiency can cause permanent damage to the brain and nervous system.

Due to the often very diverse and unspecific symptoms, a deficiency is only recognized at a late stage.

Possible symptoms of a vitamin B12 deficiency:

  • Fatigue, easy fatigue
  • confusion
  • lack of drive
  • General weakness
  • hair loss
  • paleness
  • anemia
  • dizziness
  • Poor concentration, memory problems
  • tongues burn
  • weight loss
  • Oral diaper rhagades
  • Decreased performance
  • Changes in the vaginal mucosa
  • numbness
  • Unsteady gait and increased tendency to fall
  • muscle weakness
  • Gastrointestinal complaints (e.g. nausea, vomiting, diarrhea)

Since vitamin B12 is involved in numerous processes and assumes important functions in blood formation, cell division, nerve function and metabolism, a deficiency primarily affects the blood count, nerves, mucous membranes and psyche.

Neurological symptoms of vitamin B12 deficiency include numbness, sensory disturbances, numb hands and feet, pain in the arms or legs, blurred vision, increased tendency to fall, impaired coordination. Permanent nerve damage can occur.

When cell division is impaired, the production of blood cells is hampered and anemia occurs, with very large, red blood cells. Possible symptoms are headache, fatigue, weight loss, fatigue, jaundice and increased body temperature.

Psychiatric consequences of a vitamin B12 deficiency are memory disorders, lack of concentration, confusion, dementia, irritability, depression and psychosis. In children, even brain development can be disrupted. (7)

With a vitamin B12 deficiency, the surface cells cannot grow properly, which puts a strain on the skin and mucous membranes. Skin tears in the corners of the mouth, tongue inflammation, gastrointestinal complaints and disorders of the vaginal mucosa can be symptoms of this.

What effects does a vitamin B12 deficiency have on the skin?

A vitamin B12 deficiency can become noticeable through dry skin, cracked corners of the mouth or numbness on the skin. It is also possible for the skin to appear pale or yellowish, which is due to a lack of red blood cells.

Which foods contain vitamin B12?

Vitamin B12 is found in sufficient quantities mainly in animal foods. Only microorganisms (bacteria) are able to produce vitamin B12. Animals absorb the vitamin through the food chain, so significant amounts are only found in animal products.

The following table lists good vitamin B12 suppliers:

Groceries Vitamin B12 (µg/ 100g)
beef liver 65
pork liver 39
herring 8th
beef 5
Salmon 3
Gouda cheese 1.9
chicken egg 1.8
pork meat 1
Quark 0.9
yogurt 0.5
cow milk 0.4
Chicken 0.4

Vitamin B12 is usually not present in plant products. The exception is special tuber and root vegetables, which can contain traces of the vitamin if they live in symbiosis with so-called nodule bacteria, which produce vitamin B12.

Sauerkraut but also special seaweed and shiitake mushrooms can contain traces of vitamin B12 due to the bacterial fermentation process and are therefore counted among the plant-based vitamin B12 suppliers. However, the vitamin B12 it contains is hardly bioavailable. (8th)

However, the amounts of vitamin B12 contained can be subject to massive fluctuations and therefore cannot guarantee an optimal supply.

In addition, so-called vitamin B12 analogues are contained in plant-based foods such as algae and sauerkraut. Not only do they have no vitamin effect, they can even damage the vitamin B12 supply, since the transport systems in the body are blocked.


Animal products such as meat contain a particularly large amount of vitamin B12. (Image Source: Unsplash / Emerson Vieira)

How does a vitamin B12 overdose manifest itself?

The body does not absorb excess amounts of vitamin B12 in the intestine, which is why an overdose is hardly possible. In addition, the body would simply excrete excess vitamin B12 via the kidneys.

Nevertheless, a vitamin B12 overdose can be possible if the intake is too high through an injection. This can also be the case with certain diseases such as liver metastases, polycythemia vera, leukemia and chronic liver inflammation.

Vitamin B12 from regular foods has no known side effects.

However, an increased dose of vitamin B12 in the form of infusions or injections can in some cases cause an allergic shock.

Hypersensitive people can also get side effects such as eczema or hives when used externally.

What is the daily requirement of vitamin B12?

The German Society for Nutrition recommends a daily intake of 4 micrograms of vitamin B12 for healthy adults. However, pregnant and breastfeeding women have an increased need.

A vitamin B12 deficiency occurs when the increased amount required is not met. If pregnant and breastfeeding women follow a vegan diet, they should definitely use dietary supplements because there is hardly any vitamin B12 in plants.

Estimated values ​​for the appropriate vitamin B12 intake:

persons micrograms per day
baby 0.5 - 1.4
Children 1.5 - 4.0
teenagers and adults 4.0
pregnant women 4.5
breastfeeding 5.5

Who are vitamin B12 risk groups?

Vegans and Vegetarians

Since significant amounts of vitamin B12 are only found in animal products, it is not surprising that vegans are counted among the most vulnerable risk group. Vegans completely avoid meat, milk, yoghurt and eggs, which is why they should definitely use supplements.

Vegetarians are also at higher risk because they avoid meat altogether. However, they can at least cover the daily requirement with milk products and eggs. Nevertheless, pregnant and breastfeeding women should also use preparations.

Elderly people

Older people are also among the vitamin B12 risk groups, since age-related changes in the gastrointestinal tract limit vitamin B12 supply. It is estimated that up to 15 percent of people over the age of 65 have a vitamin B12 deficiency. (9.10)

This phenomenon is known as " absorption disorder " and describes the declining production of the intrinsic factor in the stomach from the age of 50.

An insufficient intrinsic factor causes a deficiency despite adequate nutrition.

Older people also have chronic illnesses or medication that make it difficult to get adequate care.

People with certain underlying diseases

A number of underlying diseases increase the risk of vitamin B12 deficiency because they limit the absorption or storage of vitamin B12 in the body. These include, among other things:

  • Intestinal disorders (eg, celiac disease, Crohn's disease, ulcerative colitis)
  • Stomach disorders (eg, chronic gastritis, partial removal of the stomach)
  • Disease of the pancreas (exocrine pancreatic insufficiency)
  • Chronic liver diseases

People who take certain medications permanently

Numerous medications are often the cause of a vitamin B12 deficiency, especially if they are taken long-term. This includes not only gastric acid-inhibiting drugs such as antacids and proton pump inhibitors, but also special diabetes and gout drugs.

Means that are used against elevated blood lipid levels and epilepsy can also be dangerous.

Pregnant and lactating women

As the vitamin B12 requirement increases during pregnancy and lactation, a deficiency can develop very quickly in these periods and have a harmful effect on the health of mother and child. Therefore, you should definitely pay attention to a needs-based diet there.

However, caution should be exercised with liver, as it contains a lot of vitamin B12, but also a lot of vitamin A. Meat that is not well cooked or raw should not be eaten either.

Vitamin B12 deficiency: 3 effective approaches to treatment and prevention

The possible approaches to counteracting or preventing a vitamin B12 deficiency are listed below.

change nourishment

The first step would be to consume more animal foods. With a daily requirement of 4 micrograms, you can get enough vitamin B12 from animal products such as meat, fish or eggs. Liver is a very good source of vitamin B12, but is rarely consumed.

Suitable sources are, for example (per 100 g):

  • Fish: herring: 8.0 µg, salmon: 3.0 µg
  • Meat: beef: 5.0 µg; Pig: 1.0 µg; Chicken: 0.4 mcg
  • Eggs: chicken egg 1.8 µg
  • Milk and dairy products: Gouda cheese 1.9 µg, quark 0.9 µg, yoghurt 0.5 µg, cow's milk 0.4 µg

use preparations and dietary supplements

Since a purely plant-based diet cannot guarantee an adequate supply of vitamin B12, vegans in particular are advised to take vitamin B12 supplements on a permanent basis.

Vegetarians should also consider taking supplements during periods of increased demand, such as pregnancy and breastfeeding.

Perform quick test

Rapid tests can be carried out to determine a vitamin B12 deficiency. For this purpose, a small blood sample is taken from the fingertip and then sent to a diagnostics laboratory.

The laboratory then analyzes the holotranscobalamin content in the blood, i.e. the active vitamin B12. A result report then returns, which can be used to see whether there is a vitamin B12 deficiency.


Unfortunately, a vitamin B12 deficiency is not recognized until late due to its diverse and non-specific symptoms. Aside from a pale skin discoloration, skin tears at the corners of the mouth and damaged mucous membranes, there are not many other effects on the skin. A defect should be treated in any case, otherwise permanent damage can occur.

However, a deficiency can easily be remedied with a balanced and animal-based diet. Only certain risk groups such as vegans or pregnant or breastfeeding mothers should use dietary supplements. However, overdoses are hardly possible.


  1. Snow, Christopher F. "Laboratory diagnosis of vitamin B12 and folate deficiency: a guide for the primary care physician." Archives of internal medicine 159.12 (1999): 1289-1298.
  2. Shipton MJ, Thachil J. Vitamin B12 deficiency - A 21st century perspective. Clin Med (London). 2015;15(2):145-150. doi:10.7861/clinmedicine.15-2-145
  3. Bradford, Gregory S., and Charles T. Taylor. "Omeprazole and vitamin B12 deficiency." Annals of Pharmacotherapy 33.5 (1999): 641-643.
  4. Katz, Max, Sook K. Lee, and Bernard A. Cooper. "Vitamin B12 malabsorption due to a biologically inert intrinsic factor." New England Journal of Medicine 287.9 ​​(1972): 425-429.
  5. Dahele, Anna, and Subrata Ghosh. "Vitamin B12 deficiency in untreated celiac disease." The American journal of gastroenterology 96.3 (2001): 745-750.
  6. Marcuard, Stefan P., Lisa Albernaz, and Prabhaker G. Khazanie. "Omeprazole therapy causes malabsorption of cyanocobalamin (vitamin B12)." Annals of internal medicine 120.3 (1994): 211-215.
  7. Lindenbaum, John, et al. "Neuropsychiatric disorders caused by cobalamin deficiency in the absence of anemia or macrocytosis." New England journal of medicine 318.26 (1988): 1720-1728.
  8. Dagnelie, Pieter-C., Wija A. van Staveren, and Henk van den Berg. "Vitamin B-12 from algae appears not to be bioavailable." The American journal of clinical nutrition 53.3 (1991): 695-697.
  9. Source
  10. Pennypacker, Leslye C., et al. "High prevalence of cobalamin deficiency in elderly outpatients." Journal of the American Geriatrics Society 40.12 (1992): 1197-1204.
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