Trace Elements Elements Trace elements in man Trace elements in the earth The essentiality of trace elements Essential trace elements are those that respond to three criteria : •They are present in living tissues at a relatively constant concentration •They provoke similar structural and physiological anomalies in several species when removed from the organism •These anomalies are prevented or cured by supplementation with a single element The essential trace elements recognised by the WHO (1997) are Iodine, Zinc, Selenium, Copper, Molybdenum, Chromium but others are probably essential, such as Manganese, Nickel, Vanadium etc Increasingly sensitive analytical techniques will probably show that there are other essential trace elements. Understanding the impact of trace elements on metabolic processes is an area for fundamental research and implies multidisciplinary studies in the fields of biochemistry, pharmacology, toxicology, genetics, epidemiology, therapeutics and also agronomy and veterinary sciences.