Good sources are liver, kidney, meat, fish, eggs, milk and cheese.良好来源是肝，肾，肉类，鱼，蛋，牛奶和乳酪。
Vitamin B12 is not found in foods of vegetable origin.维生素B12是没有发现食品中的蔬菜产地。 Bacteria in colon also synthesize it.细菌在结肠还合成了它。 Unlike folic acid, vitamin B12 is heat stable.不像叶酸，维生素B12是热稳定。 Liver is the main storage site of vitamin B12.肝脏是主要贮存场的维生素B12 。 About 2 mg are stored in the liver and another 2 mg elsewhere in the body.约2毫克，是储存在肝脏和另外2毫克，在其他地方的机构。 These stores are sufficient to fight against any deficiency for one to three years.这些店都是足以打击任何缺失，为一至三年。
Good sources of vitamin B12 for vegetarians are dairy products or free-range eggs.良好来源，维生素B12对素食者是奶类制品或自由放养鸡蛋。 ½ pint of milk (full fat or semi skimmed) contains 1.2 µg.半品脱牛奶（全脂肪或半脱脂） ，载有1.2 μ g. A slice of vegetarian cheddar cheese (40g) contains 0.5 µg.一片素食切德奶酪（ 40克）载有0.5 μ g. A boiled egg contains 0.7 µg.一煮鸡蛋含有0.7 μ g. Fermentation in the manufacture of yoghurt destroys much of the B12 present.在发酵生产酸奶摧毁大部分的B12的。 Boiling milk can also destroy much of the B12.煮牛奶也可以摧毁大量的B12的。
Vegetarians are advised that they should ensure their diet includes foods fortified with vitamin B12.素食者均表示，他们应该确保他们的饮食习惯，包括食品强化维生素B12 。 A range of B12 fortified foods are available.一系列的B12的强化食品可供选择。 These include yeast extracts, Vecon vegetable stock, veggie burger mixes, textured vegetable protein, Soya milks, vegetable and sunflower margarines, and breakfast cereals.这些措施包括酵母提取物， vecon蔬菜股票， veggie汉堡包组合，压纹植物蛋白，大豆牛奶，蔬菜和向日葵人造黄油，和早餐谷物。
This vitamin is found in the fungus Streptomyces griseus.这种维生素被发现在该链霉菌真菌灰色。 Hence vitamin B12 is obtained as a by-product in the manufacture of Streptomycin.因此，维生素B12是得到了作为副产品在制造链霉素。
Absorption takes place from the ileum.吸收发生，从回肠。 Intrinsic factor present in the normal gastric juice is essential for the proper absorption of vitamin B12.内在因素，目前在正常胃液是必不可少的，以便适当吸收的维生素B12 。 It is stored in the liver.它是储存在肝脏中。 From the liver it passes to the bone marrow and helps in the maturation of the red cells.从肝论，它通过向骨髓，并帮助在成熟的红色细胞。 Vitamin B12 is excreted in the faeces and urine.维生素B12是在排泄粪便和尿液。
Benefits of vitamin B12益处维生素B12
Essential for the formation and maturation of red blood cells.对于形成和成熟的红血细胞。 Vitamin B12 is Castle’s extrinsic factor, which combines with the intrinsic factor present in the normal gastric juice and is absorbed.维生素B12是城堡的外在因素，并结合的内在因素，目前在正常胃液和吸收。 B12 is necessary for the rapid synthesis of DNA during cell division. B12的，是必要的，为迅速合成的DNA在细胞分裂过程。 This is especially important in tissues where cells are dividing rapidly, particularly the bone marrow tissues responsible for red blood cell formation.这一点尤其重要，在那里组织细胞分化迅速，特别是骨髓组织，负责红血细胞的形成。 If B12 deficiency occurs, DNA production is interrupted and abnormal cells called megaloblasts occur.如果B12缺乏症发生时， DNA的生产中断和异常细胞的所谓megaloblasts发生。 This results in anaemia.这一结果在贫血。 Symptoms include excessive tiredness, breathlessness, listlessness, pallor, and poor resistance to infection.症状包括过度疲倦，呼吸困难， listlessness ，脸色苍白，差抗感染。 Other symptoms can include a smooth, sore tongue and menstrual disorders.其他症状包括平稳，喉咙痛，舌头和月经失调。 Anaemia may also be due to folic acid deficiency, folic acid also being necessary for DNA synthesis.贫血，还可能是由于叶酸缺乏，叶酸也正在必要作DNA的合成。
It increases the white cell count and the platelets through its action in the bone marrow.它增加白血球计数及血小板通过其行动，并在骨髓。
Concerned with the maintenance of normal health and activity of certain parts of the nervous system.与维持正常的健康和活动的某些部分的神经系统。 Vitamin B12 not only cures the pernicious anaemia, but also the neurological manifestations of pernicious anaemia, eg sub acute combined degeneration of the spinal cord.维生素B12 ，不仅治愈恶性贫血，而且还表现的神经系统有害性贫血症，如亚急性联合变性的脊髓。
Formation of lipid from carbohydrate in influenced by vitamin B12.形成脂质来自碳水化合物的影响维生素B12 。 Hyperglycemia due to vitamin B12 deficiency can be corrected after administration of vitamin B12.高血糖是由于维生素B12缺乏可予以纠正后，政府的维生素B12 。
It also maintains the integrity of the epithelial cells especially of the mouth and the stomach.它也能够保持完整的上皮细胞，尤其是嘴和胃。
It favors the normal growth and is particularly useful in premature babies: the action is probably due to an adequate absorption of metabolic products by influencing the intrinsic factor of Castle formed in the gastric mucous membrane.它主张的正常生长，是特别有用的，在早产儿：行动可能是由于有足够的吸收代谢产物通过影响内在因素的城堡形成于胃粘膜保护膜。
It is essential for maintaining the functional integrity of the myelinated fibres of the central nervous system and the peripheral nerves.它的维持是非常重要的功能完整性有髓纤维的中枢神经系统和周围神经。
It happens to correct or prevent fatty infiltration of the liver by favoring formation of methionine and protecting the liver from injury by certain toxic agents.恰巧，以纠正或防止脂肪浸润的肝有利于形成蛋氨酸和保护肝脏的损伤，某些有毒化学物质。
Deficiency signs不足的迹象
Due to deficiency of vitamin B12 pernicious or macrocytic or megaloblastic anaemia is produced.由于缺乏症维生素B12的流毒或大细胞或巨贫血产生。
Its deficiency also causes hyperglycemia.其缺陷也可引起血糖升高。
Growth is retarded, nervousness and irritability is also observed.增长是迟钝，紧张和烦躁不安，也观察到。
Deficiency might occur as a result of lack in diet, lack of intrinsic factor as in pernicious anaemia, defective absorption due to intestinal disease, infection with microorganisms, which have affinity for vitamin B12 and thus destroy it in the intestinal tract.不足可能出现由于缺乏饮食，缺乏内在的因素，在流毒贫血，有缺陷的吸收，由于肠道疾病，感染微生物，其中有亲和力，为维生素B12 ，从而摧毁它在肠道。
Other important features in vitamin B12 deficiency in man are mucosal atrophy and inflammation of tongue, mouth etc., degenerative lesions of the posterior and lateral columns of the spinal cord.其他重要特点，在维生素B12缺乏症男子是胃粘膜萎缩和炎症的舌，口等，退行性病变的后部和侧柱的脊髓。 The patient may feel pain, tingling and numbness in the extremities and there may be partial paralysis.病人可能会觉得痛，刺痛和麻木感，在四肢，并有可能局部瘫痪。
Dietary deficiency of vitamin B12 occurs in subjects who are strict vegetarians and eat no animal products.饮食缺陷的维生素B12发生在学科的人是严格素食者，吃任何动物产品。
Daily requirement:日报要求：
The requirement is very small. 这项规定是非常小。
a) Normal adults 1mcg一）正常成人1mcg
b) Pregnancy 1.5 mcg b ）怀孕心磁1.5
c) Lactation 1.5 mcg c ）在哺乳期1.5心磁
d) Infants and children 0.2 mcg d ）在婴幼儿和儿童的心磁0.2