Zinc, magnesium, copper, and protein concentrations in human saliva: age- and sex-related differences.

Normal concentrations of trace elements in parotid saliva, supernatant- and sediment-mixed saliva, plasma, and hair were determined in 278 healthy adults grouped as young (18-29 y), middle-aged (30-64 y), and elderly (65-93 y). Age-related increases (p less than 0.05) were observed in concentrations of zinc in the supernatant of mixed saliva and parotid saliva, copper in plasma, and protein in all fractions of saliva studied. Concentrations of zinc in salivary sediment and plasma did not vary with age. Age-related decreases (p less than 0.05) were found in concentrations of magnesium in mixed-saliva supernatant, copper in salivary sediment, and zinc and copper in hair. Males had higher concentrations of zinc in plasma (p less than 0.05) and of copper in sediment (p less than 0.01) than did females but lower amounts of copper in plasma and of protein in parotid saliva (p less than 0.05). Concentrations of zinc in saliva were not correlated with those in plasma or hair. Copper in mixed-saliva supernatant was positively associated with concentrations in plasma but negatively related to concentrations in hair.