Background: Accumulating evidence from observational studies indicates that a high calcium intake may reduce body weight and body fat. However, few randomized trials have been conducted.
Objective: We examined whether calcium supplementation affects body weight and body fat in young girls and whether a relation exists between habitual calcium intake and body weight and body fat.
Design: A randomized, double-blind, placebo-controlled intervention study was conducted in 110 young girls. The subjects were randomly assigned to receive 500 mg Ca/d as calcium carbonate or placebo for 1 y. Two groups of girls were selected according to habitual calcium intake from a large group; one group consumed 1000-1304 mg/d (40th-60th percentile; n = 60) and the other group consumed <713 mg/d (<20th percentile; n = 50). Height, body weight, body fat, and calcium intake were measured at baseline and after 1 y.
Results: At baseline a significant negative correlation was observed between habitual dietary calcium intake and percentage of body fat (r = -0.242, P = 0.011). However, calcium supplementation had no effect on height, body weight, or percentage body fat.
Conclusions: Habitual dietary calcium intake was inversely associated with body fat, but a low-dose calcium supplement had no effect on body weight, height, or body fat over 1 y in young girls. It is possible that the effect of calcium on body weight is only exerted if it is ingested as part of a meal, or the effect may be due to other ingredients in dairy products, and calcium may simply be a marker for a high dairy intake.