[Essential trace elements and immunity]

The effects of zinc, iron, copper and selenium on the immune system are reviewed. Among the essential trace elements in humans, zinc, iron, copper and selenium are essential for the integrity and optimum function of the immunity. Although each element has different functions in the immune system, the deficiencies in each of these elements mainly causes the dysfunction of cell-mediated immunity. Deficiencies do not significantly effect the B cell function. These immunological abnormalities can be improved by supplementation of deficient elements. However, excess supplementation also impairs the immune system. Therefore, a proper balance of these elements is essential for maintenance of immunocompetence.