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.

Metabolic balance of manganese in young men consuming diets containing five levels of dietary manganese.

Five healthy men, ages 19-20, were fed a diet for 105 d to measure manganese balance during consumption of conventional foods. The study was divided into five periods of 21, 21, 38, 11 and 14 d, in which the daily dietary intakes of manganese (Mn) were 2.89, 2.06, 1.21, 3.79 and 2.65 mg, respectively. During the last 7 d of each dietary period, subjects resided in a metabolic unit and fasting blood samples were drawn on two mornings. Feces and urine were collected during the last 6 d and integumental losses were collected during the last 60 h of each period. The mean Mn balances for periods 1-5 were -0.083, -0.018, -0.088, +0.657 and +0.136 mg/d, respectively. Corresponding apparent retentions were -2.90, -0.88, -7.40, +17.33 and +5.12%. The mean sum of endogenous and exogenous losses when intake was theoretically zero was calculated to be 392 micrograms/d. When these total losses were combined with the mean positive retention, the theoretical mean dietary level of Mn required for positive balance for these male subjects was 3.5 mg/d or 50 micrograms/kg.

Manganese balance and clinical observations in young men fed a manganese-deficient diet.

A balance study was conducted to determine the minimum requirement for manganese (Mn) and to examine the effects of Mn depletion. Seven male subjects, age 19-22, were fed a Mn-adequate diet of conventional foods (2.59 mg Mn/d, 135 mg cholesterol, and P:S ratio of 0.86) for 3 wk to establish base-line data. Then a purified diet containing 0.11 mg Mn/d was fed for 39 d (depletion), followed by two 5-d periods of 1.53 and 2.55 mg Mn/d (repletion). Diets, feces, urine, and integument were analyzed for Mn, and blood was analyzed for Mn, cholesterol, and other constituents. Plasma levels of cholesterol decreased from 170 to 152 mg/dL during the base-line period, and then to 142 mg/dL at the end of depletion, but did not respond to 10 days of repletion. A fleeting dermatitis, Miliaria crystallina, developed in five of the seven subjects at the end of depletion, but disappeared as repletion began. The minimum requirement for Mn on this purified diet, calculated by the factorial method using Mn balance at three levels of intake was 0.74 mg/d. This requirement would be increased to 2.11 mg/d if the obligatory loss was combined with the lowest individual percentage of retention.