CLINICAL ASPECTS OF TRACE-ELEMENTS - ZINC IN HUMAN-NUTRITION - ASSESSMENT OF ZINC STATUS

Because the limiting and vulnerable zinc pool has not been identified, it becomes a challenge to determine which of the many zinc pools is m ost susceptible to deficiency. As a consequence, defining and assessin g zinc status in the individual patient is a somewhat uncertain proces s. Laboratory analysis of zinc status is difficult because no single b iochemical criterion can reliably reflect zinc body stores. Many index es have been examined in the hopes of discovering a method for the ass essment of zinc nutriture. None of the methods currently used can be w holeheartedly recommended because they are fraught with problems that after their use and interpretation. However, these methods remain in u se for clinical and research purpose, though their benefits and drawba cks must always be acknowledge. Until an acceptable method of analysis is discovered, clinicians must rely for confirmation of zinc deficien cy on process of supplementing with zinc and observing the patient's r esponse. The main indexes (plasma/serum, erythrocyte, leukocyte, neutr ophil, urine, hair and salivary zinc levels, taste acuity and oral zin c tolerance tests, and measurement of metallothionein levels) are revi ewed. Measurement of plasma or erythrocyte metallothionein levels show s promise as a future tool for the accurate determination of zinc stat us.