title: Vitamin D3 supplementation during weight loss: a double-blind randomized controlled trial.
abstract: BACKGROUND
  Vitamin D deficiency is associated with obesity; whether repletion supports weight loss and changes obesity-related biomarkers is unknown.
  
  
  OBJECTIVE
  We compared 12 mo of vitamin D3 supplementation with placebo on weight, body composition, insulin, and C-reactive protein (CRP) in postmenopausal women in a weight-loss intervention.
  
  
  METHODS
  A total of 218 overweight/obese women (50-75 y of age) with serum 25-hydroxyvitamin D [25(OH)D] ≥10 ng/mL but <32 ng/mL were randomly assigned to weight loss + 2000 IU oral vitamin D3/d or weight loss + daily placebo. The weight-loss intervention included a reduced-calorie diet (10% weight loss goal) and 225 min/wk of moderate-to-vigorous aerobic activity. Mean 12-mo changes in weight, body composition, serum insulin, CRP, and 25(OH)D were compared between groups (intent-to-treat) by using generalized estimating equations.
  
  
  RESULTS
  A total of 86% of participants completed the 12-mo measurements. The mean (95% CI) change in 25(OH)D was 13.6 (11.6, 15.4) ng/mL in the vitamin D3 arm compared with -1.3 (-2.6, -0.3) ng/mL in the placebo arm (P < 0.0001). Changes in weight [-7.1 (-8.7, -5.7) compared with -7.4 (-8.1, -5.4) kg], body mass index (in kg/m(2): both -2.8), waist circumference [-4.9 (-6.7, -2.9) compared with -4.5 (-5.6, -2.6) cm], percentage body fat [-4.1 (-4.9, -2.9) compared with -3.5 (-4.5, -2.5)], trunk fat [-4.1 (-4.7, -3.0) compared with -3.7 (-4.3, -2.9) kg], insulin [-2.5 (-3.4, -1.7) compared with -2.4 (-3.3, -1.4) μU/mL], and CRP [-0.9 (-1.2, -0.6) compared with -0.79 (-0.9, -0.4) mg/L] [corrected] were similar between groups (all P > 0.05). Compared with women who achieved 25(OH)D <32 ng/mL, women randomly assigned to vitamin D who became replete (ie, 25(OH)D ≥32 ng/mL) lost more weight [-8.8 (-11.1, -6.9) compared with -5.6 (-7.2, -5.0) kg; P = 0.05], waist circumference [-6.6 (-9.3, -4.3) compared with -2.5 (-4.6, -2.0) cm; P = 0.02], and percentage body fat [-4.7 (-6.1, -3.5) compared with -2.6 (-3.9, -2.2); P = 0.04]. Among women with complete pill counts (97% adherence), the mean decrease in CRP was 1.18 mg/mL (46%) in the vitamin D arm compared with 0.46 mg/mL (25%) in the placebo arm (P = 0.03).
  
  
  CONCLUSIONS
  Vitamin D3 supplementation during weight loss did not increase weight loss or associated factors compared with placebo; however, women who became replete experienced greater improvements. This trial was registered at clinicaltrials.gov as NCT01240213.
authors.affiliation: Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA (CM, LX, II, CD, C-YW, LK, and AM), and the Department of Epidemiology, School of Public Health (AM), the Department of Biostatistics, School of Public Health (C-YW), and the Department of Medicine (LK), University of Washington, Seattle, WA.
authors.forename: Caitlin
authors.initials: C
authors.lastname: Mason
authors.forename: Liren
authors.initials: L
authors.lastname: Xiao
authors.forename: Ikuyo
authors.initials: I
authors.lastname: Imayama
authors.forename: Catherine
authors.initials: C
authors.lastname: Duggan
authors.forename: Ching-Yun
authors.initials: CY
authors.lastname: Wang
authors.forename: Larissa
authors.initials: L
authors.lastname: Korde
authors.forename: Anne
authors.initials: A
authors.lastname: McTiernan
mesh_terms: D000368:Aged; D001823:Body Composition; D015992:Body Mass Index; D001835:Body Weight; D002097:C-Reactive Protein / Q000378:metabolism; D002762:Cholecalciferol / Q000008:administration & dosage* / Q000097:blood*; D004032:Diet; D019587:Dietary Supplements; D004311:Double-Blind Method; D002149:Energy Intake; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D016014:Linear Models; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000150:complications; D010349:Patient Compliance; D017698:Postmenopause / Q000187:drug effects; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications / Q000188:drug therapy; D055105:Waist Circumference; D015431:Weight Loss / Q000187:drug effects*
chemical_list: D007328:Insulin; D002762:Cholecalciferol; D002097:C-Reactive Protein