1 heavy metal/element in food or feed

Heavy metals are an indicator for environmental pollutions. Food, water and air are the pathway to human and animal organisms.

Another possibility is, they pass through contaminated feed or water in the animal food. Especially with marine animals can often be contaminated with an higher concentration of heavy metals. 

An ohter posibillity of contamination are from heavy metal containing materials which are in contact with the food during the processing.

supplements are needed for a lot of varius chemical processes in the human body. e.g.

Your body needs calcium for bone formation and for various metabolic processes.

Cobalt is part of the vitamin B12 complex. 

Many enzyme complexes contain magnesium. It is indispensable for the muscles and it is also needed for the synthesis of proteins.