WEST LAFAYETTE, Ind.--Researchers from Purdue University showed a high-calcium diet increased whole-body fat oxidation following a meal, while serum parathyroid hormone (PTH) levels had the opposite effect on fat oxidation. Published in the December issue of the American Journal of Clinical Nutrition (82, 6:1228-34, 2005), the study involved 19 normal-weight women aged 18 to 30, who were assigned to either a low-calcium (less than 800 mg/d, n=10) or a high-calcium diet (1,000 to 1,400 mg/d, n=9) for one year.
The scientists assessed whole-body fat oxidation by measuring respiratory gas exchange after each subject consumed two isocaloric liquid meals containing 100 mg or 500 mg calcium at baseline and one year; they also measured PTH at baseline and one year.
Results showed the mean one-year change in fat oxidation was higher in the high-calcium group, compared to the low calcium group. Also, the one-year change in serum log PTH was negatively associated with the one-year change in postprandial fat oxidation after a high-calcium meal, when controlled for the one-year change in total body fat mass.
They concluded a chronic diet high in dairy calcium increases whole-body fat oxidation following a meal, while increases in fasting serum PTH correlate to decreases in postprandial whole-body fat oxidation.
