微量元素是指人体中含量小于0.01%(100毫克/千克体重的),每日需要量在100毫克以下者称之为微量元素。其中钾、纳、钙、磷、镁等含量较多,每天需要量在100克以上的称之为常量元素。随着我国人民物质生活水平的提高,食物数量日益丰富,水平质量不断改善,城市居民对热量和蛋白质的摄取基本得到满足,一般不会缺乏。但在个别地区,由于环境中某些元素的缺乏,使水和食物中此种元素不足,引起某些特殊元素的缺乏。如老年妇女骨质 Trace elements refers to the human body content of less than 0.01% (100 mg / kg body weight), the daily requirement of 100 mg or less called trace elements. Among them, potassium, sodium, calcium, phosphorus, magnesium and other content is more, the daily requirement of more than 100 grams is called a constant element. With the improvement of the material living standards of our people, the quantity of food is becoming increasingly abundant and the quality of the environment is constantly improving, the intake of calories and proteins by urban residents is basically satisfied, and there is generally no shortage. However, in some areas, due to the lack of certain elements in the environment, such elements in water and food are not sufficient, causing some special elements to be lacking. Such as elderly women bone