[Study on calcium absorption rate in premenarche Chinese girls aged 9 - 11.5 years]

To investigate the characteristics of calcium metabolism in relation to different levels of dietary calcium intakes in premenarche Chinese girls.

Forty-nine healthy premenarche girls of Han ethic (9 - 11.5 years) were recruited, and divided into four groups respectively, receiving four different doses of calcium intakes for 6 days, 600 mg (usual diet), 900 mg (containing 250 ml of milk), 1200 mg (containing 250ml of milk and 750 mg of calcium carbonate) and 1500mg calcium (250 ml of milk and 1500 mg of calcium carbonate) per day. A 3-day urine and stool, and a 3-d duplicated food samples were collected to assess the calcium excretion in urine and feces and input of the dietary calcium during the treatment period.

There were no significant differences in appearance calcium absorption among the four groups (55%, 53%, 52% and 52%). Urine calcium is correlated negatively with dietary protein and dietary phosphorus. And no correlation was found between dietary protein and calcium absorption.

The appearance calcium absorption was (53 +/- 0.12) % in Chinese premenarche girls with dietary calcium intakes ranged between 800 to 1600 mg/d, high dietary protein intakes increase urine calcium secrete.