ESSENTIAL TRACE-METALS - NEW DEFINITIONS BASED ON NEW PARADIGMS

This article will concentrate on the nutritional and physiological asp ects of modern trace metal research. It will try to establish meaningf ul relations among the research activities of the past 50 years, and t o summarize the present state of knowledge as a basis for future endea vors. The discussion will address the gradual emergence during the pas t decades of three paradigms that can be expected to determine the dir ections of future research.