title: Skim milk powder enhances trabecular bone architecture compared with casein or whey in diet-induced obese rats.
abstract: OBJECTIVE
  We previously showed that skim milk powder (SMP) prevents weight gain more so than casein or whey alone. Dairy foods and changes in body mass can affect bone architecture; therefore, our objective was to examine the effect of dairy proteins on bone structure in the tibia of dietary-induced obese rats.
  
  
  METHODS
  Twelve-week-old diet-induced obese Sprague-Dawley rats were randomized to one of six diets that varied in protein source (casein, whey, or SMP), Ca level (0.67% or 2.4%), and energy density (high-fat/high-sucrose [HFHS], or normal energy density [NE]). After 8 wk, body composition was assessed via dual energy x-ray absorptiometry and trabecular and cortical bone parameters of the tibia were assessed using micro-computed tomography and mixed model analysis.
  
  
  RESULTS
  Rats fed SMP with 2.4% calcium had significantly lower body mass and fat mass than all other groups. The ratio of bone volume to total volume (BV/TV) was significantly higher when the HFHS diet was supplemented with SMP and 2.4% calcium compared with whey (+66.7%) or casein (+32.6%). The HFHS diet group had 49.3% greater BV/TV compared with the NE groups. Increasing the amount of calcium resulted in a significant increase in BV/TV (188.9%) in the HFHS diet groups but not in the NE groups.
  
  
  CONCLUSIONS
  The intake of skim milk powder supplemented with calcium enhances trabecular bone architecture in obese rats consuming HFHS diet to a greater extent than with either casein or whey protein alone. Bioactive ingredients in complete dairy may contribute to these effects.
authors: Department of Mechanical and Manufacturing Engineering, University of Calgary, Alberta, Canada.
authors: Aviv
authors: A
authors: Fried
authors: Sarah L
authors: SL
authors: Manske
authors: Lindsay K
authors: LK
authors: Eller
authors: Caeley
authors: C
authors: Lorincz
authors: Raylene A
authors: RA
authors: Reimer
authors: Ronald F
authors: RF
authors: Zernicke
mesh_terms: D015502:Absorptiometry, Photon; D000818:Animals; D001823:Body Composition / Q000187:drug effects; D015519:Bone Density / Q000187:drug effects; D001842:Bone and Bones / Q000187:drug effects* / Q000378:metabolism; D002136:Calcium, Dietary / Q000008:administration & dosage; D002364:Caseins / Q000008:administration & dosage*; D004032:Diet; D008297:Male; D008892:Milk / Q000737:chemistry* / Q000378:metabolism; D008894:Milk Proteins / Q000008:administration & dosage*; D009765:Obesity / Q000139:chemically induced / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014057:Tomography, X-Ray Computed; D015430:Weight Gain / Q000187:drug effects; D000067816:Whey Proteins
chemical_list: D002136:Calcium, Dietary; D002364:Caseins; D008894:Milk Proteins; D000067816:Whey Proteins