title: Dairy calcium intake, serum vitamin D, and successful weight loss.
abstract: 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.
  
  
  METHODS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: 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. dshahar@bgu.ac.il
authors.forename: Danit R
authors.initials: DR
authors.lastname: Shahar
authors.forename: Dan
authors.initials: D
authors.lastname: Schwarzfuchs
authors.forename: Drora
authors.initials: D
authors.lastname: Fraser
authors.forename: Hillel
authors.initials: H
authors.lastname: Vardi
authors.forename: Joachim
authors.initials: J
authors.lastname: Thiery
authors.forename: Georg Martin
authors.initials: GM
authors.lastname: Fiedler
authors.forename: Matthias
authors.initials: M
authors.lastname: Blüher
authors.forename: Michael
authors.initials: M
authors.lastname: Stumvoll
authors.forename: Meir J
authors.initials: MJ
authors.lastname: Stampfer
authors.forename: Iris
authors.initials: I
authors.lastname: Shai
mesh_terms: D000328:Adult; D015992:Body Mass Index; D002136:Calcium, Dietary / Q000008:administration & dosage*; D003611:Dairy Products; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000178:diet therapy*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D015431:Weight Loss
chemical_list: D002136:Calcium, Dietary; D014807:Vitamin D; C104450:25-hydroxyvitamin D