维生素是人体维持正常代谢和功能所必须的一类低分子化合物,依据其溶解性能可分为脂溶性及水溶性维生素两类。它是人体六大营养要素(糖、脂肪、蛋白质、盐类、维生素和水)之一,大多数必须从食物中获得,仅少数可在人体内合成或由肠道细菌产生。人体对维生素并不苛求,仅微小剂量即可满足多数人体一天的需要,尤其 Vitamin is a kind of low molecular compound which is necessary for the human body to maintain normal metabolism and function. According to its solubility, vitamins can be divided into two categories: fat-soluble and water-soluble vitamins. It is one of the six major nutrients of the body (sugar, fat, protein, salt, vitamins and water), most of which must be obtained from food and only a few can be synthesized in the human body or produced by gut bacteria. The human body is not demanding vitamins, only a small dose to meet the needs of most people a day, especially