Dairy calcium intake, serum vitamin D, and successful weight loss
Am J Clin Nutr (September 1, 2010). doi:10.3945/ajcn.2010.29355
Danit R Shahar, Dan Schwarzfuchs, Drora Fraser, Hillel Vardi, Joachim Thiery, Georg Martin Fiedler, Matthias Blüher, Michael Stumvoll, Meir J Stampfer and Iris Shai
1 From the S Daniel Abraham Center for Health and Nutrition and the Department of Epidemiology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel (DRS, DF, HV, and IS); the Nuclear Research Center Negev, Dimona, Israel (DS); the Department of Medicine and the Institute of Laboratory Medicine, University of Leipzig, Leipzig, Germany (JT, GMF, MB, and MS); the Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA (MJS); and the Departments of Epidemiology and Nutrition, Harvard School of Public Health, Boston, MA (MJS).
2 Supported by the Israeli Ministry of Health and the Dairy Council (grant received by DRS and DF), the Israeli Ministry of Health, Chief Scientist Office grants received by IS, DS, and A Tirosh (Israel), German Research Foundation grant (DFG) (KFO 152; grants received by MB and MS), and the Dr Robert C and Veronica Atkins Research Foundation.
3 Address correspondence to DR Shahar, The S Daniel Abraham International Center for Health and Nutrition, Department of Epidemiology and Health Services Evaluation, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 84105, Israel. E-mail: dshahar at bgu.ac.il.
Background: The role of dairy calcium intake and serum vitamin D concentrations in weight loss is controversial.
Objective: The objective was to assess the association of dairy calcium intake and serum vitamin D with weight loss.
Design: We analyzed data from participants in the 2-y Dietary Intervention Randomized Controlled Trial (DIRECT) n = 322; mean body mass index (BMI; in kg/m2): 31; mean age: 52 y. A representative sample (n = 126) was followed for 6 mo for serum vitamin D changes.
Results: Baseline serum 25-hydroxyvitamin D 25(OH)D concentrations decreased significantly across the tertiles of baseline BMI (25.6 ± 8.0, 24.1 ± 8.9, and 22.9 ± 6.8 ng/mL, respectively; P for trend = 0.02). Baseline concentrations of vitamin D and dairy calcium intake were not associated with subsequent weight loss. However, in repeated-measures models adjusted for age, sex, baseline BMI, total fat intake, and diet group assignment, higher 6-mo tertile levels of dairy calcium intake (median for tertiles: 156.5, 358.0, and 582.9 mg/d, respectively) and serum 25(OH)D (14.5, 21.2, and 30.2 ng/mL, respectively) were associated with increased weight loss across the 2-y intervention (–3.3, –3.5, and –5.3 kg, respectively, for dairy calcium; P = 0.043; –3.1, –3.8, and –5.6 kg, respectively, for vitamin D; P = 0.013). In a multivariate logistic regression adjusted simultaneously for age, sex, baseline BMI, total fat intake, diet group, vitamin D concentration, and dairy calcium, an increase of 1 SD in dairy calcium intake increased the likelihood of weight loss of >4.5 kg in the preceding 6 mo odds ratio (OR): 1.45; P = 0.046. A similar increase was seen for serum 25(OH)D at the 6-mo point (OR: 1.7; P = 0.009).
Conclusion: Our study suggests that both higher dairy calcium intake and increased serum vitamin D are related to greater diet-induced weight loss. This trial was registered at clinicaltrials.gov as NCT00160108.
Received for publication February 10, 2010. Accepted for publication August 4, 2010.