Linda D McCabe | PubMed Health

PubMed2005

Fat oxidation and its relation to serum parathyroid hormone in young women enrolled in a 1-y dairy calcium intervention.

BACKGROUND: Increased dietary calcium is associated with changes in body composition. One proposed mechanism is that dietary calcium increases fat oxidation, potentially via regulation of serum parathyroid hormone (PTH) concentrations. OBJECTIVES: The objectives of the study were to determine whether acute or chronic increased dairy calcium intakes alter postprandial whole-body fat oxidation and whether the increased intake is related to changes in PTH concentrations. DESIGN: Normal-weight women aged 18-30 y were randomly assigned to a low (<800 mg/d, control; n = 10) or high (1000-1400 mg/d; n = 9) dietary calcium intake group for 1 y. Whole-body fat oxidation was assessed by measuring respiratory gas exchange after each subject consumed 2 isocaloric liquid meals containing 100 or 500 mg Ca at baseline and 1 y. Fasting serum PTH was measured at baseline and 1 y. RESULTS: The mean 1-y change in fat oxidation was higher in the high-calcium group than in the low-calcium control group after a low-calcium meal (0.10 +/- 0.05 compared with 0.005 +/- 0.04 g/min; P < 0.001) and a high-calcium meal (0.06 +/- 0.05 compared with 0.03 +/- 0.04 g/min; P < 0.05). The 1-y change in serum log PTH was negatively associated with the 1-y change in postprandial fat oxidation after a high-calcium meal (partial r = -0.46, P < 0.04) when controlled for the1-y change in total body fat mass. CONCLUSIONS: The results suggest that a chronic diet high in dairy calcium increases whole-body fat oxidation from a meal, and increases in fasting serum PTH relate to decreases in postprandial whole-body fat oxidation.

Adipose Tissue↗

PubMed2004

Dairy intakes affect bone density in the elderly.

BACKGROUND: Race and sex differences in the effect of diet on bone mineral density (BMD) at the hip in the elderly are unknown. OBJECTIVES: This study related cross-sectional nutrient and dairy product consumption to hip BMD in white and black men and women aged >60 y and evaluated the influence of nutrient and dairy product consumption on changes in BMD in a white cohort participating in a calcium, vitamin D, or placebo trial. DESIGN: The Health Habits and History Questionnaire was used in 289 white women and 116 white men who participated in the trial and in 265 black women and 75 black men to predict total hip and femoral neck BMD or changes in BMD. RESULTS: Blacks had higher calcium intakes than did whites (700 and 654 mg/d, respectively; P = 0.0094), and men had higher calcium intakes than did women (735 and 655 mg/d, respectively; P = 0.0007). For men, the correlation between total hip BMD and dairy calcium intake after adjustment for age, race, and weight was 0.23 (P < 0.005); this relation was not significant in women (r = 0.02, P = 0.12). Similar results were found for femoral neck BMD. In the longitudinal study, calcium supplementation reduced bone loss from the total hip and femoral neck in those who consumed <1.5 servings of dairy products/d and were <72 y old. CONCLUSIONS: Cross-sectional results indicated that higher dairy product consumption is associated with greater hip BMD in men, but not in women. Calcium supplementation protected both men and women from bone loss in the longitudinal study of whites.

Age Factors↗