Calcium and dairy product modulation of lipid utilization and energy expenditure

Objective: The purpose of this study was to investigate the impact of dietary calcium or dairy product intake on total energy expenditure (TEE), fat oxidation, and thermic effect of a meal (TEM) during a weight loss trial. Methods and Procedures: The intervention included a prescribed 500-kcal deficit diet in a randomized placebo-controlled calcium or dairy product intervention employing twenty-four 18 to 31-year-old (22.2 +/- 3.1 years, mean +/- s.d.) overweight women (75.5 +/- 9.6 kg). TEM and fat oxidation were measured using respiratory gas exchange after a meal challenge, and TEE was measured by doubly labeled water. Fat mass ( FM) and lean mass (fat-free mass (FFM)) were measured by dual-energy X-ray absorptiometry. Subjects were randomized into one of these three intervention groups: (i) placebo (< 800 mg/day calcium intake); (ii) 900 mg/day calcium supplement; (iii) three servings of dairy products/day to achieve an additional 900 mg/day. Results: There were no group effects observed in change in TEE; however, a group effect was observed for fat oxidation after adjusting for FFM (P = 0.02). The treatment effect was due to an increase in fat oxidation in the calcium-supplemented group of 1.5 +/- 0.6 g/h, P = 0.02. Baseline 25-hydroxyvitamin D (25OHD) was positively correlated with TEM (R = 0.31, P = 0.004), and trended toward a correlation with fat oxidation ( P = 0.06), independent of group assignment. Finally, the change in log parathyroid hormone (PTH) was positively correlated with the change in trunk FM (R = 0.27, P = 0.03). Discussion: These results support that calcium intake increases fat oxidation, but does not change TEE and that adequate vitamin D status may enhance TEM and fat oxidation.