Dairy Calcium Intake and Relationship to Bone Mineral Density (BMD), Bone Mineral Content (BMC) and Leptin in Post- Menopausal Women

Abstract

Previous research has demonstrated that dairy calcium along with calorie restriction can contribute to weight loss while maintaining BMC and BMD. This study was a 3-month demonstration of a culturally sensitive program to evaluate the effects of dairy calcium. Caloric intake was limited to 1400 kcal/d 92% of resting energy expenditure]. A total of 56 female subjects were randomized into two equal groups receiving either low dairy calcium ~800 mg/d or high dairy calcium ~1400 mg/d intake. The age and body mass index (BMI) at baseline for the low calcium group was 54.46±7.39 years, 32.5±6.6 kg/m2 respectively; and the high calcium group was 56.75± 8.90 years, 33.5±5.8 kg/m2 respectively. Differences after 3 months in weight, BMI, leptin, BMD and BMC were analyzed. Correlations were calculated between leptin and BMD (g/cm2) or BMC (g) before and after intervention. After the intervention in the high calcium group there was an average reduction in weight -1.52±2.08 (kg), (P=0.001); BMI: -0.70±0.86 kg/m2, (p<0.001); leptin: -1.18±5.10 ng/ml, (P =0.231) BMC: -0.009±1.41, (p=0.975) and BMD: 0.001±.017, (p=0.684).  Despite a greater reduction in leptin levels in the low calcium group, changes in all parameters were not different from changes in the low calcium group with an average reduction in weight of -1.93±3.04 (kg), (p=0.002); BMI: -0.74±1.2 kg/m2, (P=0.002); leptin: -2.58±8.38 ng/ml, (P=0.114), BMC: 0.038±1.38, (P=0.887) and BMD: <0.001±.022, (P=0.912). The decrease in leptin level was not correlated with BMD and BMC in both intervention groups (all P>0.05). We observed a significant treatment effect only for leptin where the low calcium group had a bigger reduction compared to the high calcium group.  There was no significant correlation between the change in leptin, BMC and BMD.