Cobalt is also one of the essential trace elements in human body, and the tissues with the highest content in human body are liver, kidney and bone. Although cobalt is a trace mineral, it is one of the components of vitamin B 12. Once cobalt is lost, the therapeutic effect of vitamin B 12 will disappear. Cobalt combines with microorganism B 12 and enters the stomach, and then combines with "internal factors" secreted by gastric parietal cells to prevent vitamin B 12 from being destroyed by intestinal microorganisms and promote its absorption. Cobalt can also stimulate the hematopoietic system of human bones and help the human body to make red blood cells. When it is deficient, it will lead to anemia, especially for vegans. Cobalt is almost completely excreted by the kidneys and must be taken in from food.