5 Measuring intake of nutrients and their effects: the case of copper L B. McAnena and J M. OConnor, University of Ulster 5.1 Introduction In this chapter, copper is considered as a case study for the measurement of the effect of nutrient intake. The importance of the role of copper in biological systems is first explored in a brief review of selected human cuproenzymes Worldwide estimates of dietary copper requirements, and dietary recommenda tions, are discussed. Although dietary sources of copper are numerous, many Western diets appear to be barely adequate in copper. While clinical copper defi ciency is rare, usually seen only in malnourished children and premature babies or as a consequence of malabsorption, a proposed link between copper deficiency and degenerative diseases makes the question of suboptimal status an important issue. Copper toxicity, acute or chronic, is also rare, but sound limits for total intake and for levels of copper in drinking water are essential nonetheless. The assessment of nutrient intake, in general, is made difficult by the limitations asso- ciated with the available methods. Putative or traditional indicators of copper status are also subject to problems and limitations, and rarely fulfil all of the essential criteria for a good index of copper status. Functional copper status is the product of the interactions of copper with a variety of factors. Foods vary in copper content and digestibility, and the mechanisms involved in absorption are affected by a variety of luminal and systemic factors. Distribution of copper around the body occurs in two phases: transport from the intestine to the liver; nd subsequent delivery to other tissues. Problems specific to the assessment of copper absorption are discussed. Some recent advances in copper metabolism research are outlined, along with promising new areas for future study.5 Measuring intake of nutrients and their effects: the case of copper L. B. McAnena and J. M. O’Connor, University of Ulster 5.1 Introduction In this chapter, copper is considered as a case study for the measurement of the effect of nutrient intake. The importance of the role of copper in biological systems is first explored in a brief review of selected human cuproenzymes. Worldwide estimates of dietary copper requirements, and dietary recommenda￾tions, are discussed. Although dietary sources of copper are numerous, many Western diets appear to be barely adequate in copper. While clinical copper defi- ciency is rare, usually seen only in malnourished children and premature babies or as a consequence of malabsorption, a proposed link between copper deficiency and degenerative diseases makes the question of suboptimal status an important issue. Copper toxicity, acute or chronic, is also rare, but sound limits for total intake and for levels of copper in drinking water are essential nonetheless. The assessment of nutrient intake, in general, is made difficult by the limitations asso￾ciated with the available methods. Putative or traditional indicators of copper status are also subject to problems and limitations, and rarely fulfil all of the essential criteria for a good index of copper status. Functional copper status is the product of the interactions of copper with a variety of factors. Foods vary in copper content and digestibility, and the mechanisms involved in absorption are affected by a variety of luminal and systemic factors. Distribution of copper around the body occurs in two phases: transport from the intestine to the liver; and subsequent delivery to other tissues. Problems specific to the assessment of copper absorption are discussed. Some recent advances in copper metabolism research are outlined, along with promising new areas for future study