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Manganese metabolism as affected by dietary calcium and phosphorus
Abstract
Three studies were conducted to investigate the effects of dietary manganese, calcium and phosphorus on manganese metabolism. In Study I, 180 male weanling rats were fed three levels of manganese (5, 50, 500 mg/kg), two levels of calcium (5,000 and 10,000 mg/kg) and phosphorus (4,000 and 8,000 mg/kg) from two sources (source 1 was a combination of sodium phosphate and calcium carbonate, while source 2 was calcium phosphate). Manganese intake, fecal manganese excretions, whole blood, liver and brain manganese levels as well as dry rib bone weights increased as level of dietary manganese increased. Feeding of calcium phosphate increased fecal manganese losses, liver manganese concentrations and rib bone percentage ash while whole blood manganese levels were lowered. High dietary calcium levels increased fecal manganese losses and decreased liver manganese concentrations, while high dietary phosphorus levels decreased whole blood manganese levels. In Study II, young adult human subjects were fed a laboratory controlled basal diet. Two calcium salts, calcium carbonate and calcium phosphate were administered to determine utilization of manganese from a normal (basal diet) and a high manganese (basal diet + 40 mg Mn/day) diet. The higher level of dietary manganese increased fecal excretion of the mineral and apparent manganese balances, but whole blood and urinary excretion of manganese were unaffected. Addition of calcium carbonate or calcium phosphate had no significant effect on any parameter of manganese nutriture. In Study III, manganese, calcium and phosphorus intakes were retrospectively calculated from the self-recorded intakes of 12 elderly human subjects, who were fed regular and sweet acidophilus milks in addition to their normal free choice diets. Blood serum calcium and phosphorus were higher in response to the feeding of treatment milks. Although, serum manganese levels were unaffected by the different treatment of the milks, the acidophilus milk tended to lower serum manganese levels to a greater extent.
Subject Area
Nutrition
Recommended Citation
Rojhani, Arezoo, "Manganese metabolism as affected by dietary calcium and phosphorus" (1989). ETD collection for University of Nebraska-Lincoln. AAI8922450.
https://digitalcommons.unl.edu/dissertations/AAI8922450