Metabolic responses of adolescent boys to two levels of dietary magnesium and protein. I. Magnesium and nitrogen retention

Abstract

Adolescent boys, 13 to 14 years old, were subjected to identical dietary treatments with each being of 2 successive years. Treatments each lasting 15 days were: low protein, low magnesium (LPLM); low protein, high magnesium (LPHM); high protein, low magnesium (HPLM); and high protein, high magnesium (HPHM). Magnesium retentions were significantly increased by consumption of the high protein diet. This was due to decreased fecal losses without concomitant changes in urinary excretion. Regression lines of magnesium retention on intake intercepted the X axis at 7.6 mg Mg/kg when subjects were fed the low protein diet and at 4.6 mg/kg with the high protein diet. The implications of these findings for formulation of requirements are discussed.