Trace elements and inflammatory response: implications for nutritional support.

The acute-phase response to injury or infection is associated with alteration in dynamics of many trace elements, particularly iron, zinc and copper. The fall in serum iron and zinc, and rise in serum copper, are brought about by changes in the concentration of specific tissue proteins controlled by cytokines, especially interleukin 1, tumor necrosis factor, and interleukin 6. These are generally believed to be beneficial aspects of the early acute phase response. One difficulty associated with these changes is that assessment of status for these elements is particularly difficult, since plasma concentration may bear little relationship to tissue status. Simultaneous assessment of the acute-phase response, for example, serum C-reactive protein, together with trace elements and monitoring changes in concentrations, may, however, permit interpretation of trace element requirements. Suggestions are made for the requirements for these and other essential elements during enteral or intravenous nutrition, together with proposed methods of interpreting laboratory tests.