title: Effect of protein source during weight loss on body composition, cardiometabolic risk and physical performance in abdominally obese, older adults: a pilot feeding study.
abstract: OBJECTIVE
  The purpose of this pilot study was to begin to examine the effect of dietary protein source (soy protein versus non-soy protein) during weight loss on body composition, and cardiometabolic and functional decline risk factors in older, abdominally obese adults.
  
  
  METHODS
  Two-arm, single-blind, randomized, controlled trial.
  
  
  METHODS
  Wake Forest School of Medicine, Winston-Salem NC 27157, USA.
  
  
  METHODS
  25 older (68.4±5.5 years, 88% female), abdominally obese (BMI: 35.1±4.3 kg/m2; WC: 101.4±13.1 cm) men and women were randomized to participate in the study.
  
  
  METHODS
  A 12-week weight loss intervention, with participants randomized to consume soy protein-based meal replacements (S; n=12) or non-soy protein-based meal replacements (NS; n=12), in addition to prepared meals, and all participants targeted to receive an individualized caloric deficit of 500 kcal/day.
  
  
  METHODS
  Body weight and composition (assessed via DXA and CT), conventional biomarkers of cardiometabolic risk, and physical performance measures were assessed pre- and post-intervention. Additional endpoints of feasibility (accrual, participation, retention, compliance, and safety) are reported.
  
  
  RESULTS
  A total of 24 participants (87% female) completed the study (96% retention) and lost an average of 7.8±3.0 kg over the 12-week period, with no difference seen between groups (p=0.83). Although nearly all measures of global and regional body composition were significantly reduced following the 12-week intervention, differences were not observed between groups. Among cardiometabolic risk factors and physical performance measures, only diastolic blood pressure was significantly lower in the NS group compared to the S group (66.7±2.7 mmHg vs 73.5±2.7 mmHg, respectively; p=0.04). Interestingly, in groups combined, despite significant reductions in body weight and lean mass, no significant changes in 400-meter walk time (+5.3±43.4 s), short physical performance battery score (+0.1±1.0), grip strength (-0.3±3.2 kg), or relative knee extensor strength (-0.0±0.0 N/m/cm3 thigh muscle volume) were observed.
  
  
  CONCLUSIONS
  Data presented here suggest that a 12-week weight loss intervention, which incorporates S and NS meal replacement products, is associated with clinically significant weight loss and improvements in several parameters of cardiometabolic risk and unchanged physical function and strength. RESULTS do not differ by protein source and suggest that soy protein is at least as good as other protein sources for weight loss during low-calorie dietary interventions in older adults.
authors.affiliation: Kristen M. Beavers, PhD, MPH, RD, Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Medical Center Boulevard, Winston-Salem, NC 27157 USA,p 1.336.713.3741, f 1.336.713.8826, kbeavers@wakehealth.edu.
authors.forename: K M
authors.initials: KM
authors.lastname: Beavers
authors.forename: M M
authors.initials: MM
authors.lastname: Gordon
authors.forename: L
authors.initials: L
authors.lastname: Easter
authors.forename: D P
authors.initials: DP
authors.lastname: Beavers
authors.forename: K G
authors.initials: KG
authors.lastname: Hairston
authors.forename: B J
authors.initials: BJ
authors.lastname: Nicklas
authors.forename: M Z
authors.initials: MZ
authors.lastname: Vitolins
mesh_terms: D050153:Abdominal Fat / Q000378:metabolism*; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects*; D001823:Body Composition / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D031204:Caloric Restriction / Q000379:methods; D004044:Dietary Proteins / Q000494:pharmacology*; D005260:Female; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008297:Male; D062407:Meals; D053580:Muscle Strength / Q000187:drug effects* / Q000502:physiology; D009765:Obesity / Q000378:metabolism / Q000503:physiopathology*; D010865:Pilot Projects; D012306:Risk; D016037:Single-Blind Method; D030262:Soybean Proteins / Q000494:pharmacology*; D016138:Walking / Q000502:physiology; D015431:Weight Loss / Q000187:drug effects*
chemical_list: D004044:Dietary Proteins; D030262:Soybean Proteins