Vitamin B12: deficiency – symptoms – therapy

Vitamin B12: deficiency – symptoms – therapy

Vitamin B12 is essential for our cells, for the formation of blood, brain and more. However, we often do not notice for years how our memory is gradually depleted. What helps: Check for the vitamin and neutralize it with food or supplements.

Vitamin B12 deficiency is a common condition among vegans, but it affects more than just them. Of course: the vitamin is mainly found in animal products. If you eat vegan food, you must take it with dietary supplements. But some vegetarians and omnivores also have too little vitamin B12. Really large quantities are found mainly in offal and fish, that is, in products that are not on the menu of many meat eaters. Risk groups also include pregnant women, the elderly, and people with pancreatitis (inflammation of the pancreas) and type 2 diabetes.

In this article, you will learn why vitamin B12 is so important to the body, how to check your vitamin B12 levels, and what you can do about vitamin B12 deficiency.

What is Vitamin B12?

Vitamin B12 is an essential vitamin. This means that your body cannot do it on its own and you must feed it with food. In addition, like other B vitamins, it is one of the water-soluble vitamins. Water-soluble vitamins are regularly excreted by the kidneys and urine. As a rule, you must constantly swallow them because the body cannot save them. With one exception: Research shows that your body can store in the liver.

Therefore, vitamin B12 is also called cobalamin due to its chemical structure, which contains a heavy metal – cobalt. The biochemically active forms of vitamin B12 that act in the body are methylcobalamin and 5-adenosylcobalamin.

The biochemically active form of the nutrient can be used directly by the body and therefore has an immediate effect.

Vitamin B12 is very sensitive to air and light. If you prepare food, such as cooking, the food loses, on average, about twelve percent of its vitamin B12.

How does vitamin B12 affect the body?

Vitamin B12 plays an important role in many metabolic reactions. Among other things, it is involved in the metabolism of folic acid, in the formation of blood and in the breakdown of fatty acids.

Other central metabolic processes in which vitamin B12 is involved:

  • DNA formation
  • Nerve protection and regeneration
  • Cell division and respiration
  • Hematopoiesis
  • Synthesis of messengers
  • Detoxification

Vitamin B12 and folate metabolism

Folic acid, like vitamin B12, belongs to the group of B vitamins. The old names for folic acid were vitamins B9 and B11. Vitamin B12 deficiency leads to folate deficiency because the body needs vitamin B12 to convert folate to its active form. Folic acid deficiency can lead to anemia (anemia) and increase the risk of cardiovascular disease. But beware: on the other hand, excess folate can cause vitamin B12 deficiency.

Nervenzellen - Витамин B12 schützt Nerven

Vitamin B12 and blood formation

Vitamin B12 is an important aid in blood formation. This promotes the maturation process of erythrocytes, erythrocytes. Vitamin is involved in DNA formation and cell division and thus stimulates the production of red blood cells.

Vitamin B12 and nerve cells

Vitamin B12 is also often referred to as a nerve vitamin. It is responsible for the production of the myelin sheath, which surrounds nerve cells as a membrane. Myelin protects cells and supports cell-to-cell signaling.

How do I take vitamin B12?

For vitamin B12 to perform its important functions in the body, it must be taken with food or dietary supplements.

How is vitamin B12 taken from food?

Vitamin B12 that you eat first goes into the stomach. There, stomach acid releases it and binds to certain proteins. The small intestine mucosa can then absorb the vitamin in the intestines and transfer it into the blood. Transport proteins, transcobalamins, then transport vitamin B12 to all cells of the body and to the liver.

If important transport proteins are too scarce, for example due to a genetic defect, vitamin B12 cannot be properly distributed in the body. This is a possible cause of vitamin B12 deficiency.

For your vitamin B12 intake to go smoothly, your stomach, pancreas and intestines are working properly. If one of these organs is malfunctioning, it can lead to vitamin B12 deficiency. The following conditions impair vitamin B12 intake:

  • Gastritis, inflammation of the gastric mucosa
  • Injury to the small intestine, such as Crohn’s disease
  • Pancreatitis, inflammation of the pancreas

Good to Know: The body stores two to five micrograms of vitamin B12. Half of it accumulates in the liver – and can stay there for almost three years.

What foods are rich in vitamin B12?

Lebensmittel mit витамин B12 - Fleisch, Innereien, Fisch, Eier, Käse

Vitamin B12 is mainly found in animal products such as meat, fish, eggs and milk. Algae is being discussed as a vegan alternative. So far, researchers have only found a form of the vitamin that humans can assimilate in the so-called nori algae – however, the amount is too small for not everyone to assimilate this form of the vitamin. Therefore, vegans need supplements or vitamin B12-fortified foods such as juices to meet their needs.

In the following table, you will find an overview of foods that are high in vitamin B12. The daily requirement of an adult for vitamin B12 is 4.0 mcg.

Vitamin B12 content per serving (micrograms per 100 grams)

  • Meat and fish
  • Vegetarian food
  • Beef Liver – 91 mcg
  • Emmentaler – 3.1 mcg
  • Calf Liver – 60 mcg
  • Camembert 2.6 mcg
  • Pork liver – 39 mcg
  • Edam – 1.9 mcg
  • Beef Kidney – 33 mcg
  • Cottage cheese – 2.0 mcg
  • Mackerel – 9 mcg
  • Chicken Egg – 1.9 mcg
  • Herring – 8.5 mcg
  • Curd – 0.8 mcg
  • Salmon – 4.7 mcg
  • Whole milk – 0.4 mcg
  • Tuna – 4.3 mcg
  • Cream – 0.4 mcg
  • Lamb – 2.7 mcg
  • Yogurt – 0.4 mcg
  • Fillet of beef – 2.0 mcg
  • Salami – 1.4 mcg
  • Pork ham – 0.6 mcg
  • Turkey breast – 0.5 mcg

Good to know: Vitamin B12 overdose is unlikely to occur naturally. Excess vitamin B12 is usually eliminated from the body through the kidneys and urine. Only if you take high doses of vitamin B12 over a long period of time can overdose cause overexertion.

What is the daily need for vitamin B12?

For vitamin B12 to perform all its functions in the body, we must take it through food. The German Nutrition Society (DGE) significantly raised its recommendations for daily vitamin B12 intake at the beginning of 2019. She now recommends 4.0 micrograms per day for teens 13 and adults. The need for children depends on age, for example, 0.5 for children under the age of four months and 3 for children aged 10 to 13; 5 micrograms. Pregnant women need 3.5 micrograms, breastfeeding out of 4.0. micrograms per day.

The US National Institute of Health (NIH) recommends values ​​well below recent DGE guidelines. For example, teens over the age of 14 and adults should get 2.4 mcg of vitamin B12 per day. Pregnant women, on the other hand, should consume 2.6 micrograms per day and breastfeeding women 2.8 micrograms per day.

Recommendations for daily vitamin B12 intake (in micrograms, mcg):

DGE (Germany) NIH (USA)
Children 0.5 to 3.5 mcg 0.4-1.8 mcg
Adults 4.0 mcg (from age 13) 2.4 mcg (from age 14)
Breastfeeding women 5.5 μg 2.8 μg
Pregnant women 4.5 mcg 2.6 mcg

Can the body make vitamin B12 on its own?

Some animals, especially ruminants like cows, can produce vitamin B12 themselves. Numerous bacteria live in their rumen, a special anterior stomach that produces vitamin B12 from food, which is then absorbed into the bloodstream. This is why beef contains vitamin B12.

Can the human body produce vitamin B12? Scientists are still debating this. The gut bacteria in our digestive tract can probably produce vitamin B12, but they do it in the wrong place, namely in the colon. absorption of vitamin B12 into the bloodstream occurs in the small intestine. Therefore, the produced vitamin does not enter the blood and liver. Instead, it is excreted through the stool. It is still controversial whether the body’s own production of vitamin B12 can contribute to the supply of vitamin B12.

Did you know? Some vegetarian mammals don’t get enough vitamin B12 from their normal diet. Guinea pigs and rats, among other things, have found an extremely unpleasant solution to this: they eat their feces, which contains vitamin B12 produced in the colon.

Tip. Interested in learning more about your gut and gut health? Read our article on intestinal flora.

Vitamin B12 Deficiency – Causes

A Vitamin B12 deficiency is a common problem. According to research, about six percent of people under the age of 60 in the US and UK do not get enough vitamin B12, older people are increasingly .

Many of those affected probably don’t even know they are missing an important vitamin. Vitamin B12 deficiency is usually unnoticeable for a long time. Since the liver stores vitamins, it can take years for you to experience symptoms. The trick is that while stores are secretly emptying, serious long-term health problems can occur, such as anemia, nerve damage, and decreased vision.

What are the causes of vitamin B12 deficiency?

Vitamin B12 deficiency can affect anyone in principle. Those who eat unhealthy and one-sided foods may get too little vitamin B12 and eventually develop a deficiency. There are risk groups that are often affected:

  • Vegans and Vegetarians
  • Seniors
  • Pregnant and lactating women
  • People after stomach removal
  • People with chronic pancreatitis or type 2 diabetes
  • People with chronic stress

Vegetarian and vegan diet

A common cause of vitamin B12 deficiency is a vegan or vegetarian diet. Vitamin B12 is found almost exclusively in animal feed, and vegans can only meet their needs through supplementation. Vegetarians can use cheese, milk, eggs, and cottage cheese. However, these foods contain significantly less vitamin B12 than meat and fish, so a vegetarian diet is associated with an increased risk of deficiency.

Researchers are currently investigating whether the demand can be met with plant foods such as mushrooms and algae. Some algae contain, for example, vitamin B12 – however, according to research, in forms that the human body cannot use. The same may be true for shiitake mushrooms, and research is ongoing as well.

Nutrition is likely the cause of the gender difference in vitamin B12 nutrition. A study by the American Society for Microbiology found that men eat animal foods such as meat more often than women. According to the National Consumption Survey II, men are more likely to consume vitamin B12 than women.

Did you know? According to statistics, about a million people in Germany now follow a vegan diet. There are about eight million vegetarians in the world – every tenth German eats meat without meat.

Vitamin B12 deficiency in old age

Age is also a risk factor. In Germany, almost

people over 65 suffer from vitamin B12 deficiency. This is partly due to the fact that older people often suffer from chronic diseases, take various medications, and that eating habits change with age. In addition, the elderly produce less stomach acid. However, stomach acid is required to release vitamin B12 from food so that it can be absorbed into the bloodstream.

Vitamin B12 deficiency in pregnant and lactating women

Pregnant and breastfeeding women should not only provide themselves with vitamin B12 – the teenage child also wants to get his share. Therefore, they have increased demand and must urgently avoid underdelivery. Because the supply of vitamin B12 plays a crucial role in the physical and mental development of unborn and newborn children. In the worst case, extreme vitamin B12 deficiency during pregnancy can even lead to miscarriage.

Diseases and operations

People suffering from pancreatitis, an inflammation of the pancreas, often suffer from vitamin B12 deficiency. They lack the enzyme trypsin, which is essential for the absorption of vitamin B12.

According to research, even people with type 2 diabetes who take metformin often have vitamin B12 problems. Metformin appears to interfere with vitamin absorption.

In addition, after gastric surgery, you must ensure that you receive vitamin B12 through dietary supplements. The stomach plays a decisive role in the use of vitamin B12, after its removal or reduction, its intake is often disrupted.

Vitamin B12 deficiency – symptoms and consequences

The symptoms of vitamin B12 deficiency are varied and often nonspecific, making them difficult to identify.

What are the symptoms of vitamin B12 deficiency?

Vitamin B12 is involved in numerous metabolic processes in the body and thus provides energy, among other things. Vitamin B12 deficiency affects mental and physical performance and therefore results in decreased performance. The following symptoms may also appear:

  • Fatigue and exhaustion
  • Headache and difficulty concentrating
  • Digestive problems
  • Depression

Even if none of the mentioned symptoms appear: extreme vitamin B12 deficiency can have health consequences if it goes unnoticed or is not treated for a long time.


If the body lacks vitamin B12, there is a violation of cell division in the bone marrow. As a result, fewer red blood cells can be produced there. Result: the so-called pernicious anemia, a special form of anemia. This anemia is accompanied by pallor, fatigue, and decreased performance and concentration.

Lack of oxygen

Vitamin B12 deficiency also affects oxygen transport. Vitamin B12 helps iron in the blood – iron, in turn, transports oxygen throughout the body. Too little oxygen in the body goes hand in hand with decreased performance and concentration, immunodeficiency, exhaustion and fatigue.

Nervous disorders and depression

Vitamin B12 is responsible for protecting nerve cells. If the vitamin cannot fulfill this duty due to a deficiency, fewer nerve fibers are formed in the spinal cord. It can cause neurological symptoms such as:

  • Nervousness and irritability
  • Pain, numbness, or “ant walking” in hands, arms, legs and feet
  • Fatigue
  • Depression

Scientists are currently still investigating the exact link between vitamin B12, folate, and depression. The general theory goes back to the amino acid homocysteine. If there is a lack of vitamin B12 in the body, there is too much homocysteine ​​- such an excess of the amino acid can damage brain tissue and interfere with signal transmission. This, in turn, leads to mood swings and depression.

It is also being tested to see if supplements with vitamin B12, folate and vitamin B6 can relieve symptoms of depression. The results are not clear yet. Some researchers recommend taking folic acid (800 mcg per day) and vitamin B12 (1 milligram per day) to support depression therapy.

Vitamin B12 deficiency and dementia

The symptoms of severe vitamin B12 deficiency are similar to those of other neurological diseases – pain and numbness can also occur with herniated discs. This is why vitamin B12 deficiency is often diagnosed very late.

In the long term, a vitamin B12 deficiency can lead to nerve cell damage and anemia – and possibly dementia in Alzheimer’s. make it more likely. The relationship has yet to be elucidated, and research has yet to come up with any consistent results. However, there are indications that an optimal supply of B vitamins and folic acid may contribute to mental performance in old age.

Alzheimer’s dementia is a brain disorder that almost always occurs in people over the age of 60. According to one study, it affects 14 percent of people over 70 and 37 percent of people over 90. Alzheimer’s disease mainly manifests itself through disorders of memory, orientation and language, as well as personality changes.

Vitamin B12 deficiency and cardiovascular disease

Vitamin B12 deficiency can contribute to the development of cardiovascular diseases such as heart failure, stroke, and heart attack.

What is common between vitamin B12 and the cardiovascular system? This is primarily the amino acid homocysteine. Vitamin B12 breaks down homocysteine ​​and converts it into other substances that promote folate metabolism. If your body lacks enough vitamin B12, it lowers the level of homocysteine ​​in your body. The concentration of the amino acid increases, and with it the risk of atherosclerosis, that is, calcification and narrowing of the blood vessels. This, in turn, is one of the strongest risk factors for heart attack, stroke, and other cardiovascular diseases.

Good to know: cardiovascular disease is the cause of one third of deaths worldwide – and the trend is growing.

Other possible consequences of vitamin B12 deficiency

decreased vision can also be a sign of cobalamin deficiency. The involvement of vitamin B12 in certain substances and messenger hormones can also lead to mental disorders such as depression or even psychosis.

With a lack of vitamin B12, energy metabolism is disrupted, which can lead to muscle weakness, exhaustion, fatigue and poor concentration. The deficiency can also manifest as upset stomach, such as loss of appetite, diarrhea, constipation, and inflammatory reactions in the mouth, stomach and intestines.

Vitamin B12 Test

a blood test tells you how much vitamin B12 you have. Various values ​​can be measured. Holotranscobalamin (Holo-TC) is considered a particularly significant parameter. Holotranscobalamin is a transport form of vitamin B12 that is bound to proteins in the blood. It is the only form that can be absorbed by all cells in the body. Too low a Holo-TC value is an early sign of vitamin B12 deficiency.

How can I get my vitamin B12 tested?

You can have a vitamin B12 test done by a physician or alternative physician, among others. An alternative is a home test such as the cerascreen® Vitamin B12 test.

For the test, take a few drops of blood from your fingertips and send the blood sample to our specialized laboratory. After the assessment, you will receive a detailed report of the results with the value of Holotranscobalamin, as well as specific recommendations for action to increase vitamin B12 levels.

Vitamin B12 deficiency therapy

If you find a vitamin B12 deficiency or a vitamin B12 deficiency, the decision is clear: you need to increase your vitamin supply. stanozolol injection online The steps you need to take depend on the degree of insufficient supply. If you have a severe deficiency, you should see your doctor to find out if the deficiency could have implications for your health.

There are three main ways to improve your vitamin B12 supply:

  • Consciously add more vitamin B12 foods to your menu
  • Take Vitamin B12 Supplements in Tablets, Capsules or Drops
  • Use syringes with high doses of vitamin B12

How can I cover my daily needs with food?

Vitamin B12 from food is found only in animal products. If you are an adult and not breastfeeding, you can cover your daily needs with 100 g of tuna, 150 g of lamb, or salmon. Vegetarian alternatives are 200g cottage cheese or two chicken eggs.

But keep in mind that vitamin B12 can be lost depending on how you prepare your food. The vitamin is very sensitive to heat and light. Heat can destroy the vitamin, so the vitamin B12 content of food is reduced by frying or cooking.

When will I receive vitamin B12 injections?

Vitamin B12 can also be injected into muscles. These injections are dosed very high. Doctors usually prescribe them to quickly replenish empty vitamin B12 stores. In this case, you usually get an injection once a month. Vitamin B12 injections are especially suitable for people who have problems with digestion so that insufficient amounts of vitamin B12 pass from the stomach into the bloodstream .

Vitamin B12 Supplements

To compensate for vitamin B12 deficiency, you can take high doses of the medication. Dietary supplements usually come in capsule or drop form and are often vegan. Good vitamin B12 supplements contain the vitamin in one of its active forms, methylcobalamin or adenosylcobalamin. Then they talk about high bioavailability – the body can quickly and effectively use the drug.

Supplements should not contain any additives that could reduce the effectiveness of the vitamin. Again, it makes sense to combine it with substances that promote absorption in the body. Vitamin B12 works well with other B vitamins and folic acid.

How do I dose vitamin B12?

How much vitamin B12 you need to reach and maintain healthy levels cannot be said at all – it varies from person to person. Internet recommendations range from 10 to 1,000 micrograms per day. The FDA recommends that vitamin B12 supplements be taken in just one dose for an extended period of 25 micrograms per day – higher doses are suggested to increase the risk of lung cancer, according to recent research. >

According to some studies, doses of 500 to 2000 micrograms per day may be helpful in compensating for the deficiency. For example, it might make sense to take a dose of 1000 mcg, first daily, then weekly, and then monthly when the vitamins level again.

Vitamin B12 supplementation through toothpaste?

Do you need to meet vitamin B12 requirements when brushing your teeth? This should actually work, according to new research. Vitamin B12-fortified toothpaste was able to improve B12 scores in study participants. The vitamin is absorbed through the oral mucosa when brushing your teeth. This is useful for people whose gastrointestinal tract is impaired and cannot take drugs from drops and capsules effectively.

Can I Overdose on Vitamin B12?

So far, there have been no reports of acute vitamin B12 overdose. The body can excrete excess water-soluble vitamin through the kidneys. Therefore, it has long been considered harmless to take vitamin B12 as a precautionary measure – especially for vegans who are often deficient.

Vitamin B12 and Cancer Risk

However, recent studies show that very high levels of vitamin B12 are not complete. It may increase the risk of cancer, especially lung cancer.

A team of international researchers analyzed various studies using data from more than 80,000 patients. Result: Elevated vitamin B12 levels increase the risk of lung cancer, especially among smokers. This analysis confirmed the results of other studies in recent years that link long-term use of vitamin B12 supplements to lung cancer.

The increased risk is especially important for people who take high doses of vitamin B12 for a long time, even if they already have high blood counts.

Therefore, it is best not to experiment. When taking nutritional supplements, follow the recommendations of your doctors, therapists, and supplement manufacturers. With a vitamin B12 test, you can tell if your values ​​are too low – in which case you can also take high-dose drugs for a short time.

Vitamin B12 – at a glance

What is vitamin B12?

Vitamin B12 is a water-soluble vitamin that must be taken through food or supplements.

What does vitamin B12 do in the body?

The main tasks of the vitamin are blood formation, protection of nerve cells, cell division and support of folic acid metabolism.

How do I get enough vitamin B12?

Vitamin B12 is found in animal feed. It remains to be seen if you can cover your needs with plant foods such as algae or mushrooms. Pregnant women, lactating women, the elderly and people with gastrointestinal diseases need more vitamin B12.

What are the causes of vitamin B12 deficiency?

There is often a deficiency due to a vegan, vegetarian, or simply insufficient diet. Other causes include medications that suppress stomach acid, certain diseases such as diabetes and pancreatitis, and genetic metabolic disorders.

What are the symptoms of vitamin B12 deficiency?

Vitamin B12 deficiency has been linked to depression, digestive problems, anemia, poor concentration, and nervous disorders. A severe deficiency can reduce performance and contribute to the development of cardiovascular disease and dementia.

What Can I Do With Vitamin B12 Deficiency?

If you find a deficiency, for example on a blood test, you can correct it with a targeted diet rich in vitamin B12, or with dietary supplements or injections.

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