[Trace elements: biological role and nutritional aspects for humans].

The methodological approaches generally adopted to ascertain the essentiality of trace elements present in human beings at levels of the order of magnitude of 1 micrograms g-1 or less are illustrated. An element is recognized as essential when it has a well defined function (as stabilizer, structural, hormonal or as enzymatic cofactor) and when it is always present in tissues and organs in well defined concentration ranges, when it induces reproducible physiological effects, when it is possible to prevent and treat consequences due to its deficiency by its supplementation. For the trace elements Co, Cr, Cu, Fe, I, Mn, Se and Zn a short summary of their biological functions in humans is presented.

Levels of some trace elements in selected autopsy organs, and in hair and blood samples from adult subjects of the Italian population.

This study, which is part of a research program for the determination of trace element reference levels in various human tissues for the Italian population, presents the concentrations of Se, Hg, Cr, Cs, Sc, Rb, Zn, Fe, Co, and Sb in lung, liver, spleen, and kidney autopsy samples taken from 14 adult subjects of the Italian population who died from accidental causes. Concentrations of the same trace elements are given also for blood and hair samples taken from subjects of the general Italian population and of a population group living in a small coastal town that has an average annual fish consumption well above the national average. The analytical method used was Instrumental Neutron Activation Analysis.

The concentration of some trace elements in human milk from Italy.

The concentration of some trace elements has been measured in samples of breast milk collected from several subjects over a period of about 1-3 months starting 15 days post-partum. A decrease of Zn concentration during the lactation period was observed in all subjects. The marked relation existing between dietary intake and milk content of trace elements is confirmed by the finding that Cs concentration in diet, fresh waters and human milk samples from Latium were one to two orders of magnitude higher than those measured in a small town in the south of Italy.

Mercury levels in food and its intake in high-risk population groups.

The mercury levels in many diet samples collected in 5 groups of normal Italian adult population were measured and compared to those referred to an area well known for its high environmental mercury content. In the same subjects, the hair and blood concentration of mercury was evaluated and related to the dietary intake. In fact, the somatic and cytogenetic effects due to the mercury contamination are mainly correlated with the blood and hair content of mercury.

Studies on the trace element distribution in the diets and population of Italy.

For various reasons an increasing importance has been given in recent time in many parts of the world to the evaluation of the trace element pathways from environment to man. In Italy a large program was recently started based on the study in different groups of population of the relationship existing between the trace element dietary intake and the trace element content in the total excretion and in some human tissues (mainly blood). In this paper the complete data concerning the daily dietary intake, the urinary and fecal excretion, and the blood concentration referred to five population groups living in different regions of Italy will be reported.