Nutrition impacts the development of the immune system, both in the growing fetus and in the early months of life. Nutrients are also necessary for the immune response to pathogens so that cells can divide and produce antibodies and cytokines. Many enzymes in immune cells require the presence of micronutrients,and critical roles have been defined for zinc, iron,copper, selenium, vitamins A, B6, C, and E in the maintenance of optimum immune function