Zinc is a very important trace element for all organisms and also for humans. Specially, in humans the body growth and development strictly depends on zinc levels. The nervous system along with the reproductive and immune systems are predominantly influenced by zinc deficiency. They can also get affected by increased levels of zinc too. The relationship between zinc and the immune system is very complex, as there are four different types of influence and effect that are associated with zinc. First, the dietary consumption and the resorption of zinc depends mostly on the composition of the diet and on age and disease status. Secondly, zinc is a cofactor among more than 300 enzymes that are influencing several organ functions and also have a secondary effect on the immune system. Thirdly, there are direct effects of zinc on the production, maturation and function of leucocytes, also known as white blood cells. And fourth, zinc influences the function of immune-stimulants that are used in the experimental systems. These are the four types of influence of zinc supplementation on the immune function.

Source: Rink L, Gabriel P. Zinc and the immune system. Proc Nutr Soc. 2000; 59(4):541-552. doi:10.1017/s0029665100000781