Diff: Vitamin B12
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'''Vitamin B12''', also known as cobalamin, is a water-soluble vitamin that plays a crucial role in various physiological processes within the human body. It is essential for the formation of red blood cells, neurological function, and the synthesis of DNA. Vitamin B12 is unique among the B vitamins as it requires intrinsic factor, a protein produced in the stomach, for optimal absorption. Since the human body cannot produce vitamin B12, it must be obtained through dietary sources or supplements. |
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==Overview== |
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Water-Soluble Vitamin: |
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Essential Nutrient: Vitamin B12 is an essential nutrient required for the proper functioning of the human body. |
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Coenzyme: It serves as a coenzyme for various enzymatic reactions. |
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Unique Absorption Mechanism: |
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Intrinsic Factor: Vitamin B12 absorption depends on intrinsic factor, a protein produced in the stomach. |
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==Functions of Vitamin B12== |
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Red Blood Cell Formation: |
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Erythropoiesis: Vitamin B12 is crucial for the production of red blood cells, preventing megaloblastic anaemia. |
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Neurological Function: |
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Nerve Myelination: It plays a role in the myelination of nerve fibres, supporting proper neurological function. |
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Neurotransmitter Synthesis: Vitamin B12 is involved in the synthesis of neurotransmitters. |
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DNA Synthesis: |
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Nucleic Acid Synthesis: Vitamin B12 is necessary for the synthesis of DNA, supporting cellular replication. |
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Homocysteine Metabolism: |
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'''Vitamin B12''', also called '''cobalamin''', is a water-soluble vitamin needed for red blood cell formation, DNA synthesis, and normal nerve function. It is naturally found in foods from animals and is added to some fortified foods and supplements. |
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Homocysteine Conversion: Vitamin B12, along with other B vitamins, helps convert homocysteine to methionine, reducing the risk of cardiovascular disease. |
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==Dietary Sources of Vitamin B12== |
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Animal Products: |
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Vitamin B12 contains cobalt, which is why compounds with B12 activity are called cobalamins. |
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Meat: Beef, pork, lamb, and poultry. |
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== Function == |
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Vitamin B12 helps the body: |
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Fish: Salmon, trout, tuna, and sardines. |
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* Make red blood cells. |
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* Maintain the nervous system. |
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* Make DNA. |
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* Use folate properly. |
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* Process some fatty acids and amino acids. |
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Shellfish: Clams, oysters, and mussels. |
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Deficiency can affect the blood, nerves, brain, mouth, gut, and general energy levels. |
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Dairy: Milk, cheese, and eggs. |
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== Food Sources == |
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Natural sources include: |
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Fortified Foods: |
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* Meat. |
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* Fish. |
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* Shellfish. |
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* Eggs. |
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* Milk, cheese, and yoghurt. |
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Fortified Cereals and Plant-Based Milk: Some plant-based products are fortified with vitamin B12. |
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Plant foods do not naturally provide reliable vitamin B12 unless fortified. Fortified breakfast cereals, fortified plant drinks, nutritional yeast with added B12, and supplements can be important for vegans and some vegetarians. |
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Supplements: |
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== Absorption == |
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Vitamin B12 in food is released during digestion, then binds to intrinsic factor, a protein made in the stomach. It is absorbed in the final part of the small intestine. |
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Vitamin B12 Supplements: Available in various forms, including tablets, capsules, and injections. |
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==Recommended Daily Intake== |
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Varied Requirements: The recommended daily intake varies by age, sex, and life stage. For adults, it is generally around 2.4 micrograms. |
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==Deficiency and Excess== |
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Deficiency Symptoms: |
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Absorption can be reduced by autoimmune gastritis, stomach or bowel surgery, some bowel diseases, low stomach acid, and some medicines. Older adults and people who avoid animal foods are at higher risk of deficiency. |
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Pernicious Anaemia: A severe deficiency can lead to pernicious anaemia, characterized by fatigue, weakness, and neurological symptoms such as tingling and numbness. |
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== Deficiency == |
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Vitamin B12 deficiency may cause: |
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Excess Intake: |
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* Tiredness and weakness. |
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* Pale or yellowish skin. |
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* Sore red tongue or mouth ulcers. |
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* Pins and needles. |
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* Numbness. |
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* Balance or walking changes. |
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* Memory, mood, or thinking changes. |
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* Visual disturbance. |
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* Megaloblastic anaemia. |
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Low Risk: Vitamin B12 is water-soluble, and excess amounts are typically excreted in urine, posing a low risk of toxicity. |
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==Interactions and Considerations== |
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Intrinsic Factor: |
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Neurological symptoms can occur even without anaemia, so normal haemoglobin does not always rule out clinically important deficiency. |
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Intrinsic Factor Production: Conditions affecting intrinsic factor production, such as pernicious anaemia, can impact vitamin B12 absorption. |
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== Diagnosis and Treatment == |
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Diagnosis may involve symptoms, blood count, vitamin B12 levels, and sometimes additional tests. NICE guidance covers recognising, diagnosing, and managing vitamin B12 deficiency in people aged 16 and over. |
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Medication Interactions: |
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Treatment depends on the cause and severity. NHS guidance describes hydroxocobalamin injections for vitamin B12 deficiency anaemia, while oral replacement can be suitable in some circumstances. People with absorption problems may need long-term treatment. |
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Proton Pump Inhibitors and H2 Blockers: Long-term use of these medications may reduce vitamin B12 absorption. |
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==Research and Health Benefits== |
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Cognitive Function: |
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== Supplements and Safety == |
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Vitamin B12 supplements are available in tablets, sprays, drops, and injections. High-dose products are common because only a portion may be absorbed. Vitamin B12 has low toxicity, but unnecessary supplementation can confuse investigation of symptoms if started before testing. |
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Cognitive Decline: Some studies explore the association between adequate vitamin B12 levels and reduced risk of cognitive decline. |
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== See Also == |
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* [[Vitamin_C]] |
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* [[Common_Medical_Terms]] |
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* [[Depression]] |
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Cardiovascular Health: |
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== References == |
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* [https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/ NIH Office of Dietary Supplements: Vitamin B12 health professional fact sheet] |
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* [https://ods.od.nih.gov/factsheets/VitaminB12-Consumer/ NIH Office of Dietary Supplements: Vitamin B12 consumer fact sheet] |
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* [https://www.nice.org.uk/guidance/ng239 NICE: Vitamin B12 deficiency in over 16s] |
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* [https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/symptoms/ NHS: Vitamin B12 or folate deficiency symptoms] |
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* [https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/treatment/ NHS: Vitamin B12 or folate deficiency treatment] |
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* [https://www.nhsinform.scot/illnesses-and-conditions/nutritional/vitamin-b12-or-folate-deficiency-anaemia/ NHS inform: Vitamin B12 or folate deficiency anaemia] |
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* [https://medlineplus.gov/ency/article/002403.htm MedlinePlus: Vitamin B12] |
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Homocysteine Levels: Research suggests that maintaining optimal vitamin B12 levels may help regulate homocysteine levels, reducing cardiovascular risk. |
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[[Category:Nutrition]] |
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[[Category:Medicine]] |