Vitamins

维生素

The term "vitamin" is used to describe certain organic compounds that are needed by the body but that cannot be manufactured by the body. They mainly serve as catalysts for certain reactions in the body. If these catalysts are missing, as in a vitamin deficiency, normal body functions can break down amd make a person more susceptible to disease. The amounts of vitamins required are very small, perhaps hundredths of grams. Vitamins are mainly obtained from our foods, but there are some special cases. Vitamin K is manufactured in our bodies in certain bacteria in our intestines, and vitamin D is produced with the help of ultraviolet radiation on our skin.

‘维生素’一词用来描述某些身体所需的有机化合物，这些化合物无法由身体自行制造。它们主要作为体内某些反应的催化剂。如果这些催化剂缺失，如在维生素缺乏的情况下，正常的生理功能会受到影响，使人体更容易患病。所需维生素的量非常小，可能仅为百分之一克。维生素主要通过食物获得，但也有特殊情况。维生素K是由体内肠道中的某些细菌制造的，而维生素D则是在皮肤受到紫外线照射时产生。

Vitamins are classified as either fat-soluble (lipid soluble) or water-soluble. Vitamins A, D, E and K are lipid-soluble and accumulate within the fat stores of the body and within the liver. The lipid-soluble vitamins are often associated with toxicity when taken in large amounts.

维生素根据是否溶于脂类分为脂溶性维生素和水溶性维生素。维生素A、D、E和K是脂溶性的，它们在体内脂肪储存和肝脏中积累。脂溶性维生素在大量摄入时往往会产生毒性。

Vitamin C and the B vitamins are water soluble. When water-soluble vitamins are taken in excess, they are readily excreted in the urine and not usually associated with toxicity. There is some storage of vitamins C and B in the liver.

维生素C和B族维生素是水溶性的。当水溶性维生素摄入过量时，它们很容易通过尿液排出，通常不会引起毒性。维生素C和B族维生素在肝脏中有一些储存。

Common Vitamins and Their Functions 常见维生素及其功能
Vitamin 维生素	Chemical Name 化学名称	Function 函数
A₁	retinol 视黄醇	Necessary for protein synthesis 蛋白质合成所必需的
A₂	3-dehydroretinol 3-去氢视黄醇	Prevents night blindness 预防夜盲
B₁	thiamine 硫胺素	Necessary for carbohydrate metabolism, prevents beri-beri 是糖代谢所必需的，可预防脚气病
B₂	riboflavin 核黄素	Acts as an oxygen carrier to the cell; prevents lesions of the mouth, eyes and skin. 作为细胞的氧载体，防止口腔、眼睛和皮肤的损伤。
B₆	pyridoxine 吡哆醇	Takes part in the decarboxylation of amino acids; alleviates dermatitis, irritability, and apathy 参与氨基酸的脱羧反应；缓解皮炎、易怒和冷漠
B₁₂	cobalamin 钴胺素	Synthesizes certain amino acids; prevents pernicious anemia. Contains the metal cobalt. 合成某些氨基酸；预防恶性贫血。含有金属钴。
C	ascorbic acid 抗坏血酸	Needed in the formation of tissue, prevents scurvy 在组织形成中必需，可预防坏血病
D₂	calciferol (activated ergosterol) 钙化固醇（激活的ergosterol）	Increases the absorption of calcium and phosphorous from the small intestine. 增加小肠对钙和磷的吸收。
D₃	activated 7-dehydrocholesterol 激活的7-脱氧胆固醇	Prevents rickets 预防佝偻病
E	alpha-tocopherol α-生育酚	Antioxidant; no known therapeutic use 抗氧化剂；尚无已知的治疗用途
K	...	The anti-hemorrhaging vitamin. 抗止血维生素

From Shipman & Wilson, Intro to Physical Science

来自 Shipman & Wilson 的《物理科学导论》

The word vitamin comes from the word "vitamine" which was coined by researchers in 1912 to describe this recently discovered class of substances. At that time they were thought to be all amines which were essential to life. But not all of the vitamin are amines, so the "e" at the end was dropped to retain the now common term for these nutritional supplements.

‘维生素’这个词来源于‘维生素’一词，该词于1912年由研究人员创造，用来描述这一类新发现的物质。当时人们认为所有维生素都是胺类物质，对生命是必要的。但并非所有维生素都是胺类，因此词尾的‘e’被去掉，以保留现在常用的这些营养补充剂的术语。

Contributing author: Serena Baxter

贡献作者：Serena Baxter

Index

Biochemical concepts

Chemistry concepts

Reference
Shipman and Wilson
Ch 15

索引生物化学概念化学概念参考 Shipman 和 Wilson 第15章

HyperPhysics*****Chemistry

HyperPhysics ***** 化学

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