title: Effect of increased intake of skimmed milk, casein, whey or water on body composition and leptin in overweight adolescents: a randomized trial.
abstract: BACKGROUND
  Dairy proteins may support muscle protein synthesis and improve satiety in adults. However, there are limited studies using exact measures of body composition, especially in adolescents.
  
  
  OBJECTIVE
  This study investigates the effect of milk proteins and water on body composition and leptin in overweight adolescents.
  
  
  METHODS
  Subjects (n = 193) aged 12-15 years were randomized to drink 1 L d(-1) of skimmed milk, whey, casein (all milk-based drinks 35 g protein L(-1) ) or water for 12 weeks. Twenty participants dropped out. A pre-test control group of 32 adolescents was examined 12 weeks before start of intervention. Outcomes included leptin and dual-energy X-ray absorptiometry scanning. The effects of the milk-based drinks on body composition and leptin were compared with baseline, pre-test control and water.
  
  
  RESULTS
  Lean mass index (LMI) increased compared to baseline (all 95% confidence intervals 0.05-0.50 kg m(-2) , all P ≤ 0.009) and the pre-test control group (0.044-0.247 kg m(-2) , P ≤ 0.002) for all four test drinks. Fat mass index (FMI) increased only for milk-based drink groups compared with baseline (0.15-0.67 kg m(-2) , P < 0.001) and also compared with water (0.029-0.255 kg m(-2) , P ≤ 0.011). For pre-test control, there was no change in FMI or LMI. Leptin increased in the casein (1.016-3.246 ng mL(-1) , P < 0.001; 0.952-3.294 ng mL(-1) , P < 0.001) and whey groups (0.135-2.273 ng mL(-1) , P = 0.027; 0.069-2.322, P = 0.038) compared with water and pre-test control group, respectively.
  
  
  CONCLUSIONS
  Although milk proteins increased LMI in overweight adolescents, there was a concurrent increase in FMI and leptin, whereas water only resulted in increased LMI. Thus, increased water intake may be beneficial for body composition in overweight adolescents.
authors.affiliation: Department of Nutrition, Exercise and Sports, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: A
authors.initials: A
authors.lastname: Larnkjaer
authors.affiliation: Department of Nutrition, Exercise and Sports, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: K
authors.initials: K
authors.lastname: Arnberg
authors.affiliation: Department of Nutrition, Exercise and Sports, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: K F
authors.initials: KF
authors.lastname: Michaelsen
authors.affiliation: Department of Nutrition, Exercise and Sports, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: S M
authors.initials: SM
authors.lastname: Jensen
authors.affiliation: Department of Nutrition, Exercise and Sports, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: C
authors.initials: C
authors.lastname: Mølgaard
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D017195:Adolescent Nutritional Physiological Phenomena; D000328:Adult; D000818:Animals; D015415:Biomarkers / Q000097:blood; D001823:Body Composition; D002364:Caseins / Q000008:administration & dosage / Q000009:adverse effects*; D003611:Dairy Products / Q000009:adverse effects*; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D020738:Leptin / Q000097:blood*; D008297:Male; D008892:Milk; D063766:Pediatric Obesity / Q000097:blood / Q000209:etiology*; D014867:Water / Q000008:administration & dosage; D000067796:Whey / Q000008:administration & dosage
chemical_list: D015415:Biomarkers; D002364:Caseins; D020738:Leptin; D014867:Water
keywords: Body composition; casein; leptin; milk; water; whey