Ultra Trace Elements and Selenium

During the past decade there has been a large upsurge in interest in nutritionally essential trace elements. In the clinical field the recognition that deficiency can occur in human subjects in many practical dietary situations has been of crucial importance from the public health viewpoint worldwide. In this chapter we review briefly our knowledge of the ultra trace elements chromium, manganese, nickel, and silicon; the remaining space is devoted to selenium because recent findings in the People's Republic of China are of particular interest in medicine. A full understanding of the role of a given trace element in human subjects can be achieved only when the detailed biochemical role of the element is elucidated; therefore the biochemistry of the various elements is also considered insofar as it is understood.