Healthy Weight

Low Calcium Intake Linked to Higher Body Fat in Children

North American Association for the Study of Obesity
(11/2005)

Some data suggest calcium or dairy products are associated with body fat loss or prevention of fat gain, but few studies have been conducted in children. We conducted a 2-y prospective study in healthy Caucasian girls, initially premenarche and aged 10.5 +/- 0.7 y. Body composition (% body fat and % trunk fat) by dual-energy x-ray absorptiometry, height, weight, and Tanner breast stage were assessed at baseline and annually thereafter. Total calcium intake (food and supplements) and dairy calcium intake were assessed twice yearly using a calcium-specific, validated, interviewer-administered food frequency questionnaire (FFQ). Three-day food records were also kept. Physical activity (hr/wk) was assessed twice yearly by interview. Of 51 girls enrolled, 46 completed all measurements. At baseline, participants were 147.4 +/- 6.7 cm tall, weighed 40.3 +/- 7.5 kg, had 24.8 +/- 9.1% body fat and 20.0 +/- 9.7% trunk fat. During the study girls gained 13.7 +/- 2.7 cm height, 13.2 +/- 4.9 kg weight, 3.8 +/- 3.3 kg fat, 1.5 +/- 4.9% body fat and 2.9 +/- 5.4% trunk fat.

Calcium intake and physical activity did not change over time and values at different times were highly correlated. Mean FFQ total calcium was 838 +/- 352 mg/d, dairy calcium was 650 +/- 351 mg/d, and mean physical activity was 9.9 +/- 3.5 hr/wk. Each girl's 2-y averages for these variables were used in regression models to predict baseline, 1-y, 2-y, and 2-y change in % body fat and % trunk fat. Regression models also included height, baseline age, Tanner breast stage, and energy intake. Both total and dairy calcium negatively predicted % body fat and % trunk fat at all cross-sectional time points. Dairy calcium was a slightly stronger predictor than total calcium, explaining 9.2 - 15.7% of % fat variance (significance of F change 0.023 - 0.004). Physical activity was also a negative predictor of % total and trunk fat at baseline and 2 y. However, no variables entered equations to predict 2-y change in % fat. In conclusion, calcium intake was cross-sectionally associated with % fat in peripubertal girls, but did not predict change in % fat over 2 y.