The mineral balance of young Japanese children

Abstract

In order to estimate the daily intake of calcium, phosphorus, magnesium, iron, zinc, copper, sodium and potassium and to establish their balanced requirement value, two kinds of survey were made of young children at a welfare facility in Osaka prefecture. In survey I, mineral balance tests were performed in order to assess the nutritional status of 18 male and 15 female children (aged from 3y5m to 6y9m) provided with a normal daily diet. In survey II, balance studies of calcium, phosphorus, magnesium, iron, zinc and copper were performed on 15 children (10 male and 5 female aged from 3y10m to 6y5m) receiving two levels of dietary protein which were composed of 2.7 and 2.0 g/kg body weight.1) The minerals exhibited the positive retention in a daily normal diet. The magnesium, phosphorus, zinc and copper requirements were estimated as 2.6mg/kg, 27.2mg/kg, 197pμg/kg and 36.8 μg/kg body weight respectively.2) The amount of calcium retention and urinary excretion were not influenced by a decrease in the dietary protein level from 2.7 to 2.0g/kg body weight. However the percentage of urinary calcium excretion showed a higher value, the protein content was increased to the level of a normal daily diet. The amount of urinary excretion of phosphorus increased and retention decreased at the higher protein level compared to the lower protein level (Low protein diet). In regard to the balance of magnesium, urinary excretion was less at the lower level of protein. Intake of copper increased and that of zinc decreased at the lower level of protein compared to the higher protein diet.