Cobalt is associated with vitamin B12. Cobalt is used in the human body to help absorb and process vitamin B12. This vitamin is essential for making red blood cells in the body. Vitamin B12, also called cobalamin, is a water-soluble vitamin that has a key role in the normal functioning of the brain and nervous system via the synthesis of myelin (myelinogenesis), and the formation of red blood cells. It is one of the eight B vitamins.