硒是地质环境中含量稀少,分布极不均一的一种生物必需微量元素。当硒的分布受自然和人为的因素影响而超出正常范围时,就会给人类和动物带来病害。大量的流行病学调查、动物观察和试验表明:饲料硒过少可引起动物发生白肌病、营养性肝坏死和渗出性素质等缺硒病;主食硒过少可引起人的肝、心肌损害、肌缺养症和贫血等,还能使克山病、大骨节病和癌症等发病率或死亡率增高。 Selenium is a kind of bio-essential trace element which is scarce in the geological environment and has a very uneven distribution. When the distribution of selenium by the natural and human factors out of the normal range, it will bring disease to humans and animals. A large number of epidemiological investigations, animal observations and experiments show that: feed too little selenium can cause animals with white muscle disease, nutritional liver necrosis and exudative quality selenium deficiency disease; staple food too little can cause human liver and myocardial damage , Muscle deficiency and anemia, but also to Keshan disease, Kashin-Beck disease and cancer incidence or mortality increased.