Effect of habitual dietary calcium intake on calcium supplementation in 12-14-y-old girls.
BACKGROUND
There is no agreement on how much calcium young girls need for optimal bone mineralization.


OBJECTIVE
We evaluated whether the effect of calcium supplementation on whole-body bone mineral accretion depends on habitual calcium intake.


METHODS
This was a randomized, double-blind, placebo-controlled, 1-y calcium intervention study of girls aged 12-14 y selected from a larger group according to habitual calcium intake: subgroup A (n = 60) habitually consumed 1000-1307 mg/d (40th-60th percentile), and subgroup B (n = 53) habitually consumed <713 mg/d (<20th percentile). The girls from each subgroup were randomly assigned to receive either 500 mg Ca/d or placebo. Whole-body bone mineral content (BMC), bone area (BA), bone mineral density (BMD), and BMC adjusted for BA, height, and weight (size-adjusted BMC) were measured at baseline and after 1 y.


RESULTS
There was no significant effect modification of baseline habitual calcium intake on the relation between calcium supplementation and height, weight, BMC, size-adjusted BMC, BA, BMD, or alkaline phosphatase. Calcium supplementation had an effect on BMD (0.8%; P = 0.049) and tended to show signs of an effect on size-adjusted BMC (0.5%; P = 0.08).


CONCLUSIONS
A modest effect of calcium supplementation on BMD was shown. However, the effect was independent of habitual calcium intake.
Mølgaard
Christian
C
Department of Human Nutrition and Centre for Advanced Food Studies, The Royal Veterinary and Agricultural University, Frederiksberg, Denmark. cm@kvl.dk
Thomsen
Birthe L
BL
Michaelsen
Kim F
KF
D000293:Adolescent; D000886:Anthropometry; D015519:Bone Density / Q000187:drug effects*; D002118:Calcium / Q000008:administration & dosage* / Q000494:pharmacology; D002136:Calcium, Dietary / Q000008:administration & dosage* / Q000494:pharmacology; D002648:Child; D004311:Double-Blind Method; D015444:Exercise; D005260:Female; D006801:Humans
D002136:Calcium, Dietary; D002118:Calcium