[10][35]: 972  However, looking at the same scientific evidence, the European Food Safety Authority (EFSA) sets adequate intake (AI) at 4.5 μg/day for pregnancy and 5.0 μg/day for lactation. In pernicious anemia, there is a lack of IF due to autoimmune atrophic gastritis, in which antibodies form against parietal cells. Vitamin B12 deficiency has been observed in between 40% and 80% of the vegetarian population who do not also take a vitamin B12 supplement or consume vitamin-fortified food. A healthcare professional typically administers these injections into a muscle every other day for 2 weeks, or until the individual’s symptoms improve. Some people have difficulties absorbing vitamin B12 from food sources and may need to take supplements. Auch bei Dehydrierung steigt der Wert, normalisiert sich jedoch wieder bei einer entsprechenden Aufnahme von Flüssigkeit. [6] The EAR for vitamin B12 for women and men ages 14 and up is 2.0 μg/day; the RDA is 2.4 μg/day. However, these symptoms are nonspecific and are not enough to diagnose vitamin B12 deficiency. Diagnosis is supported based on vitamin B12 blood levels below 150–180 pmol/L (200–250 pg/mL) in adults. Bacterial fermentation creates AdoB12 and MeB12, which are converted to cyanocobalamin by addition of potassium cyanide in the presence of sodium nitrite and heat. hat said, even slightly lower-than-normal levels of vitamin B12 can trigger symptoms. Sind meine Vitamin B12-Werte zu hoch? Es ist wichtig, sorgfältig zu kontrollieren, wie viel Vitamin B12 Sie konsumieren, um sicherzustellen, dass Sie nicht zu viel oder zu wenig konsumieren. [57][58] A table of the old and new adult daily values is provided at Reference Daily Intake. Zu einem symptomatischen Vitamin-B12-Mangel gehören offiziell insbesondere die perniziöse Anämie und auch die genannte Hunter-Glossitis. Approximately 0.1% of this is lost per day by secretions into the gut, as not all these secretions are reabsorbed. Cyanocobalamin is a manufactured form of B12. 1. The average adult should get 2.4 micrograms (mcg) of vitamin B12 a day, according to the National Institutes of Health. [6][12][23] Vitamin B12 deficiency can also cause symptoms of mania and psychosis. Here are some of the best foods with B12: Foods with B12 are always the first choice, but if you have trouble eating B12-rich foods, or have problems absorbing B12, another potential vitamin B12 source is a multivitamin. Canned tuna fish, 3 ounces: 2.5. Um den Alltag meistern zu können, benötigt der menschliche Körper ausreichend Vitamin B12. Dann sollte zusätzlich keine hoch dosierte Folsäure genommen werden. [63] Non-ruminant, non-hindgut herbivores may have an enlarged forestomach and/or small intestine to provide a place for bacterial fermentation and B-vitamin production, including B12. The sixth coordination site, the reactive center, is variable, being a cyano group (–CN), a hydroxyl group (–OH), a methyl group (–CH3) or a 5′-deoxyadenosyl group. [134], Five people have been awarded Nobel Prizes for direct and indirect studies of vitamin B12: George Whipple, George Minot and William Murphy (1934), Alexander R. Todd (1957), and Dorothy Hodgkin (1964). 100ml soya milk (fortified) = 0.4mcg. THF may be regenerated via MTR or may be obtained from fresh folate in the diet. [97] Four of the six coordination sites are provided by the corrin ring, and a fifth by a dimethylbenzimidazole group. [92][93] Deficiency does not develop if dietary intake of vitamin B12 is adequate or prophylactic B12 supplementation is given. Even though vitamin B12 is found in a variety of foods, some people are at an increased risk of developing B12 deficiency or insufficiency. RDA for lactation equals 2.8 μg/day. [73][74][75] Other types of algae are rich in B12, with some species, such as Porphyra yezoensis,[73] containing as much cobalamin as liver. Any medical information published on this website is not intended as a substitute for informed medical advice and you should not take any action before consulting with a healthcare professional. Top foods with B12. [48][49] The mechanism of action is straightforward: the hydroxycobalamin hydroxide ligand is displaced by the toxic cyanide ion, and the resulting non-toxic cyanocobalamin is excreted in urine.[50]. For this reason, it is recommended for those following vegan diets to supplement with B12. Pregnancy and lactation can worsen deficiency in vegans. Amounts and Dosage. RDAs. After his death in 1984, other physicians and naturopaths took up prescribing "intravenous micro-nutrient therapy" with unsubstantiated health claims for treating fatigue, low energy, stress, anxiety, migraine, depression, immunocompromised, promoting weight loss and more. [2] Foods containing vitamin B12 include meat, clams, liver, fish, poultry, eggs, and dairy products. lactis is used, as the bacteria can utilize the pseudovitamin despite it being unavailable to humans. Das liegt zum Beispiel daran, dass in sehr vielen Fällen, die Darmflora nicht im Einklang ist, was die Verwertung hemmt. [32] Vegetarians—people who consume animal byproducts such as dairy products and eggs, but not the flesh of any animal—are also at risk. However, it is common for older people to have some level of B12 deficiency. [19] Pseudovitamin B12 is the majority corrinoid in spirulina, an algal health food sometimes erroneously claimed as having this vitamin activity. [2] Supplements and medications are available to treat and prevent vitamin B12 deficiency. Nahrungsmittel mit Vitamin B12. [67] Insects are a source of B12 for animals (including other insects and humans). The culture medium for LLD required liver extract. The body can store vitamin B12 for up to 4 years, and it can get rid of any excess or unwanted vitamin B12 in the urine. Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. [81], Injection of hydroxycobalamin is often used if digestive absorption is impaired,[2] but this course of action may not be necessary with high-dose oral supplements (such as 0.5–1.0 mg or more),[82][83] because with large quantities of the vitamin taken orally, even the 1% to 5% of free crystalline B12 that is absorbed along the entire intestine by passive diffusion may be sufficient to provide a necessary amount. [2][7] Only some archaea and bacteria can synthesize vitamin B12. [36] The EFSA also reviewed the safety question and reached the same conclusion as in the United States—that there was not sufficient evidence to set a UL for vitamin B12. Apps to accelerometers: Can technology improve mental health in older adults? MNT is the registered trade mark of Healthline Media. As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Es ist essenziell für die Blutbildung, den Fett- und Eiweißstoffwechsel und die Zellerneuerung. Vitamin B12 is an essential vitamin found in foods such as meat, fish, and dairy. You can learn more about how we ensure our content is accurate and current by reading our. We include products we think are useful for our readers. Vitamin B12, required for proper brain function and a host of chemical reactions within the body, is found naturally only in animal foods. Most healthy adults get sufficient B12 from their regular diet. People with pernicious anemia may lack vitamin B12. Vitamin B12 (cobalamin) is crucial for nerve tissue, brain function, and red blood cells. If you buy through links on this page, we may earn a small commission Here’s our process. Our team thoroughly researches and evaluates the recommendations we make on our site. Mögliche Symptome Vitamin B12 ist von großer Bedeutung für den menschlichen Körper. [108] This pattern of B12 transfer to a special binding protein secreted in a previous digestive step, is repeated once more before absorption. [91], Reduced serum levels of vitamin B12 occur in up to 30% of people taking long-term anti-diabetic metformin. RDA for pregnancy equals 2.6 μg/day. [35]: 974–975  Risk of deficiency persists if the post-weaning diet is low in animal products. Signs of a deficiency include headaches and fatigue. Nach dem aktuellen Stand der Forschung, kann Vitamin B12 über Lebensmittel wie Fleisch, Fisch, Meeresfrüchte, Eier und Milchprodukte aufgenommen werden. The MUT function is necessary for proper myelin synthesis. Ankylosing Spondylitis Pain: Fact or Fiction, https://rarediseases.org/rare-diseases/anemia-pernicious/, https://www.ncbi.nlm.nih.gov/books/NBK441923/, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6413093/, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4964408/, https://ijponline.biomedcentral.com/articles/10.1186/s13052-020-0804-x, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7077099/, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5065578/, http://aop.sagepub.com/content/early/2016/06/17/1060028016655180.abstract, https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/, http://www.nhs.uk/Conditions/Anaemia-vitamin-B12-and-folate-deficiency/Pages/Causes.aspx, https://pubmed.ncbi.nlm.nih.gov/26296064/, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6770181/, Almond yogurt is the dairy alternative with the most nutrients, study finds, Cutting carbohydrates from breakfast may help people with diabetes, Sleep apnea may lead to loss in brain volume, accelerate Alzheimer's, Consuming too much salt may raise risk of hypertension-linked dementia, Scientists find 16 genes that increase risk for heart attacks in women. Unless a vegan diet is carefully planned, it is difficult to get enough vitamin B12 through plant foods alone. Vitamin B12 is an essential vitamin mainly found in animal products. 100% fortified breakfast cereal (check the label), 1 serving: 6, Fortified soy milk, chocolate (check the label): 1.7. Health Alerts from Harvard Medical School. Vitamin B12 is the most chemically complex of all the vitamins. In the US, non-prescription products can be purchased providing up to 5,000 µg each, and it is a common ingredient in energy drinks and energy shots, usually at many times the recommended dietary allowance of B12. Several methods have been used to determine the vitamin B12 content in foods including microbiological assays, chemiluminescence assays, polarographic, spectrophotometric and high-performance liquid chromatography processes. Patients with this disorder do not have enough intrinsic factor (IF), a protein in the stomach that allows the body to absorb vitamin B12. [44] In addition, elevated methylmalonic acid levels may also be related to metabolic disorders such as methylmalonic acidemia. [6][51][69], Natural plant and algae sources of vitamin B12 include fermented plant foods such as tempeh[70][71][72] and seaweed-derived foods such as nori and laver. Wie viel Vitamin B12 braucht man? Die Beantwortung der Fragen dauert nur 1-2 Minuten. Symptomatic vitamin deficiency is more likely if the person is rendered achlorhydric (a complete absence of gastric acid secretion), which occurs more frequently with proton pump inhibitors than H2 blockers. Gastric acid releases the vitamin from food particles; therefore antacid and acid-blocking medications (especially proton-pump inhibitors) may inhibit absorption of B12. Das tut er vor allem in der Leber. Der Körper braucht es vor allem zur Bildung roter Blutkörperchen, wichtiger Nervenbotenstoffe und neuen Erbguts (DNA). Vitamin B12, das Mediziner auch Cobalamin nennen, ist von großer Bedeutung für den Organismus eines Menschen. Learn what foods to…, Medical News Today has strict sourcing guidelines and draws only from peer-reviewed studies, academic research institutions, and medical journals and associations. Insufficient vitamin B12 can also lead to anemia. Investigating the power of music for dementia. 100g mackerel = 9.1mcg. [115][116], Species from the following genera and the following individual species are known to synthesize B12: Propionibacterium shermanii, Pseudomonas denitrificans, Streptomyces griseus, Acetobacterium, Aerobacter, Agrobacterium, Alcaligenes, Azotobacter, Bacillus, Clostridium, Corynebacterium, Flavobacterium, Lactobacillus, Micromonospora, Mycobacterium, Nocardia, Proteus, [128][130], While working at the Bureau of Dairy Industry, U.S. Department of Agriculture, Mary Shaw Shorb was assigned work on the bacterial strain Lactobacillus lactis Dorner (LLD), which was used to make yogurt and other cultured dairy products. [84], A person with cobalamin C disease (which results in combined methylmalonic aciduria and homocystinuria) may require treatment with intravenous or intramuscular hydroxocobalamin or transdermal B12, because oral cyanocobalamin is inadequate in the treatment of cobalamin C disease. People with anemia might also experience: Several groups of people may be at an increased risk of vitamin B12 deficiency. The next binding protein for B12 is intrinsic factor (IF), a protein synthesized by gastric parietal cells that is secreted in response to histamine, gastrin and pentagastrin, as well as the presence of food. (AIs are established when there is insufficient information to determine EARs and RDAs.) Plus, get a FREE copy of the Best Diets for Cognitive Fitness. [52], The Japan National Institute of Health and Nutrition set the RDA for people ages 12 and older at 2.4 μg/day. Sign up now and get a FREE copy of theBest Diets for Cognitive Fitness. These chemical compounds have a similar molecular structure, each of which shows vitamin activity in a vitamin-deficient biological system, they are referred to as vitamers. [77] Since only bacteria and some archea possess the genes and enzymes necessary to synthesize vitamin B12, plant and algae sources all obtain the vitamin secondarily from symbiosis with various species of bacteria,[5] or in the case of fermented plant foods, from bacterial fermentation. [2][4] Plants do not need cobalamin and carry out the reactions with enzymes that are not dependent on it. An average brand may contain about 25 mcg, which is more than 400% of the recommended daily value. [15] It is a deep red solid that dissolves in water to give red solutions. It can result in irreversible and potentially severe damage, especially to the nervous system and brain. * Adequate Intake (AI) Sources of Vitamin B12. Das Eisen wird vom Körper zur Bildung von sogenannten Hämgruppen benötig. [9] A second major cause is age-related decline in stomach acid production (achlorhydria), because acid exposure frees protein-bound vitamin. The complete laboratory synthesis of B12 was achieved by Robert Burns Woodward[124] and Albert Eschenmoser in 1972. This came to be known as the Myers' cocktail. Vitamin B12 is a water-soluble vitamin, like all other B vitamins. Welche Nahrungsmittel sind reich an Vitamin B12? [64] Soil that is deficient in cobalt may result in B12 deficiency, and B12 injections or cobalt supplementation may be required for livestock. All rights reserved. Die Aufnahme (Resorption)von Vitamin B12 kann nur über die Nahrung erfolgen. [129] Edwin Cohn prepared a liver extract that was 50 to 100 times more potent in treating pernicious anemia than the natural liver products. [45] If nervous system damage is present and blood testing is inconclusive, a lumbar puncture may be carried out to measure cerebrospinal fluid B12 levels. Other useful sources include most meat, salmon, cod, milk, cheese . [47] Injection side effects include skin rash, itching, chills, fever, hot flushes, nausea and dizziness. [10] In the absence of enterohepatic reabsorption, only months to a year of vitamin B12 are stored. This protects the vitamin from degradation in the acidic environment of the stomach. Davon profitieren die Menschen, wenn sie tierische Produkte verzehren. Es zählt zu den wasserlöslichen Vitaminen und ist als solches das einzige, das unser Körper mehrere Jahre lang speichern kann. When the body does not have enough B12, it leads to decreased normal red blood cell production (anemia), which impairs oxygen delivery. Readily absorbed in distal half of the ileum. [2] They are taken by mouth, but for the treatment of deficiency may also be given as an intramuscular injection.[2][6]. Der menschliche Organismus bildet den Nährstoff nicht selbst. Thus all of the DNA synthetic effects of B12 deficiency, including the megaloblastic anemia of pernicious anemia, resolve if sufficient dietary folate is present. [70][71], The Academy of Nutrition and Dietetics considers plant and algae sources "unreliable", stating that vegans should turn to fortified foods and supplements instead. The total amount of vitamin B12 stored in the body is about 2–5 mg in adults. Is the ketogenic diet right for autoimmune conditions? A serious deficiency can be corrected with B12 shots or high-dose supplements. Da der Körper Vitamin B12 nicht selbst herstellen kann, muss es über die Nahrung aufgenommen werden. Symptome Diagnose Behandlung Eine Vitamin-B6-Toxizität ist selten, kann aber durch die Einnahme hochdosierter Vitamin-B6-Präparate entstehen. Once consumed, cyanocobalamin is converted to the biologically active AdoB12 and MeB12. [112], Vitamin B12 is derived from a tetrapyrrolic structural framework created by the enzymes deaminase and cosynthetase which transform aminolevulinic acid via porphobilinogen and hydroxymethylbilane to uroporphyrinogen III. 100g lamb liver = 83mcg. Vitamin B 12 (Cobalamin) ist entscheidend für das gesunde Wachstum von Kindern. Was ist Transferrin? Read on to learn more about this condition, such as its potential causes and risks, symptoms, and treatment…, Vitamin A is a vital nutrient for healthy vision, skeletal tissue, hair, and skin. The hydrogenases and, by necessity, enzymes associated with cobalt utilization, involve metal–carbon bonds. Er muss es daher über die Nahrung aufnehmen. denitrificans. [51][2][66] For humans, the bioavailability from eggs is less than 9%, compared to 40% to 60% from fish, fowl and meat. Vitamin B12 supplements are available as single or multivitamin tablets. Denn es wirkt unter anderem bei der Blutbildung, dem Fett- und Eiweißstoffwechsel sowie der Erneuerung Ihrer Zellen mit. [102] This functionality is lost in vitamin B12 deficiency, and can be measured clinically as an increased serum methylmalonic acid (MMA) concentration. The ability to shuttle between the +1, +2, and +3 oxidation states is responsible for the versatile chemistry of vitamin B12, allowing it to serve as a donor of deoxyadenosyl radical (radical alkyl source) and as a methyl cation equivalent (electrophilic alkyl source). Vitamin B12 ist ein lebenswichtiges Vitamin. Hydroxocobalamin injections may cause side effects, including: Serious side effects are rare. [39], Vegan advocacy organizations, among others, recommend that every vegan consume B12 from either fortified foods or supplements. In the UK, standard initial therapy consists of intramuscular injections of 1000 μg of hydroxocobalamin three times a week for two weeks or until neurological symptoms improve, followed by 1000 μg every two or three months. unter einem Vitamin-B12-Mangel zu leiden . "Pseudovitamin B12" refers to compounds that are corrinoids with a structure similar to the vitamin but without vitamin activity. What are the symptoms of vitamin B-12 deficiency? BONUS! Vitamin B12 is crucial to various bodily processes, including: Vitamin B12 is essential for healthy blood. Vegans face a risk of vitamin B12 deficiency, as their diet excludes animal-sourced food products. Was Deine Darmgesundheit mit Vitamin B12 zu tun hat. Targeted delivery of vitamin B12 is a major focus of modern prescriptions. [89], Pseudovitamin-B12 can show up as biologically active vitamin B12 when a microbiological assay with Lactobacillus delbrueckii subsp. This depletion can lead to anemia, and also an increased risk that their breastfed infants become vitamin deficient. [42], According to one review: "At present, no 'gold standard' test exists for the diagnosis of vitamin B12 deficiency and as a consequence the diagnosis requires consideration of both the clinical state of the patient and the results of investigations. For other uses of B12, see, This article is about the family of vitamins. [128] In 1934, George Whipple shared the 1934 Nobel Prize in Physiology or Medicine with William P. Murphy and George Minot for discovery of an effective treatment for pernicious anemia using liver concentrate, later found to contain a large amount of vitamin B12. [94], Certain medications can decrease the absorption of orally consumed vitamin B12, including colchicine, extended-release potassium products, and antibiotics such as gentamicin, neomycin and tobramycin. As isolated as an air-stable solid and available commercially, cobalt in vitamin B12 (cyanocobalamin and other vitamers) is present in its +3 oxidation state. Eine Mangelernährung führt zu Entwicklungsverzögerungen. [2], Sublingual methylcobalamin, which contains no cyanide, is available in 5 mg tablets. B12 deficiency has been linked to an increased risk of cognitive impairment and depression. Vitamin B12 gehört zu den wasserlöslichen Vitaminen. Während ein Vitamin-B12-Mangel seit Langem als Ursache für Anämie und neurologische Defizite bekannt ist, wurde erst in den letzten Jahrzehnten mehr darauf geachtet, dass auch ein erhöhter Vitamin-B12-Spiegel mit verschiedenen, meist schwerwiegenden Krankheitsentitäten assoziiert ist. Swimming and skin: What to know if a child has eczema. [5], Vitamin B12 is the most chemically complex of all vitamins,[6] and for humans, the only vitamin that must be sourced from animal-derived foods or from supplements. Nehmen Sie ausreichend Vitamin B12 zu sich? For children aged 1–17 years the AIs increase with age from 1.5 to 3.5 μg/day. Frühe Anzeichen einer Vitamin-D-Toxizität sind Appetitlosigkeit, Übelkeit und Erbrechen, gefolgt von Schwächegefühl, Nervosität und Bluthochdruck. [106], Methionine synthase, coded by MTR gene, is a methyltransferase enzyme which uses the MeB12 and reaction type 2 to transfer a methyl group from 5-methyltetrahydrofolate to homocysteine, thereby generating tetrahydrofolate (THF) and methionine.