Dairy calcium intake, serum vitamin D, and successful weight loss.

Am J Clin Nutr. 2010 Sep 1.
Shahar DR, Schwarzfuchs D, Fraser D, Vardi H, Thiery J, Fiedler GM, Blüher M, Stumvoll M, Stampfer MJ, Shai I.
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.

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/m(2)): 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. PMID: 20810979