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: [email protected].

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.