Metabolic responses of adolescent boys to two levels of dietary magnesium and protein. II. Effect of magnesium and protein level on calcium balance

Abstract

Adolescent boys, 13 to 14 years old, were subjected to identical dietary treatments in each 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). Calcium intake was constant throughout at 1.8 g/day. Urinary calcium excretion was significantly increased by increasing the dietary protein level. Apparent absorption was also increased, but significance of the effect was reduced by variability and a trend toward decreasing absorption with time. Changes in dietary magnesium level did not appear to affect apparent Ca absorption or urinary excretion.