Effect of calcium supplementation on weight and fat loss in women

Abstract

Data suggest that a diet deficient in calcium is associated with higher body weight and that augmenting calcium intake may reduce weight and fat gain or enhance loss. Our aim was to determine whether calcium supplementation during a weight loss intervention affects body fat or weight loss. Data were combined from three separate 25-wk randomized, double blind, placebo-controlled trials of 1000 mg/d calcium supplementation in 100 premenopausal and postmenopausal women. The primary outcome measures were change in body weight and fat mass adjusted for baseline values. There were no significant differences in body weight or fat mass change between the placebo and the calcium-supplemented groups in the pooled analysis (adjusted mean +/- SE; body weight, placebo -6.2 +/- 0.7 vs. Ca -7.0 +/- 0.7 kg; fat mass, placebo -4.5 +/- 0.6 vs. Ca -5.5 +/- 0.6 kg), and no significant interactions of calcium supplementation with menopausal/diet status. Analysis as separate trials also found no significant differences between the placebo and the calcium groups. Calcium supplementation did not significantly affect amount of weight or fat lost by women counseled to follow a moderately restricted diet for 25 wk. Nevertheless, the magnitude and direction of the differences for group means are consistent with a hypothesized small effect.

Fig. 1

Initial characteristics of subjects who completed the studies. ¹Assessed for eligibility: this was tabulated for two of the eight recruitments. In these two recruitments, we have data to show that 7% of the subjects screened were eligible for recruitment into the study (40 eligible subjects from 584 individuals that were interviewed). For 162 women who were recruited, it can be estimated that we screened 2365 subjects during this 4.5-yr period. ²Reasons for exclusion: due to noninvasive measures in this study and access to weekly weight loss sessions with a registered dietitian, there were almost no obese persons who refused to participate if they were eligible (weekly classes were available either weekdays or weekends to accommodate individual schedules). Those who were not eligible either had a disease state or medication known to influence calcium metabolism and were therefore excluded.