title: Effect of beta-hydroxy-beta-methylbutyrate supplementation on muscle loss in older adults: a systematic review and meta-analysis.
abstract: BACKGROUND
  Beta-hydroxy-beta-methylbutyrate (HMB), a metabolite of the branched-chain amino acid leucine, has been investigated as a potential supplement to improve muscle quality; however, whether HMB supplementation has beneficial effects on muscle loss in older adults remains unclear.
  
  
  METHODS
  Systematic review with meta-analysis.
  
  
  METHODS
  PubMed, Medline and EMBASE databases were searched from the earliest possible year to September 2014.
  
  
  METHODS
  Individuals aged 65 years and older that reported absolute changes in body composition with use of HMB.
  
  
  METHODS
  Two review authors working independently reviewed the trials, and standard mean difference was calculated using a fixed effects model.
  
  
  RESULTS
  A total of seven randomized controlled trials were included, in which 147 older adults received HMB intervention and 140 were assigned to control groups. The meta-analysis showed greater muscle mass gain in the intervention groups compared with the control groups (standard mean difference=0.352kg; 95% confidence interval: 0.11, 0.594; Z value=2.85; P=0.004). There were no significant fat mass changes between intervention and control groups (standard mean difference=-0.08kg; 95% confidence interval: -0.32, 0.159; Z value=0.66; P=0.511).
  
  
  CONCLUSIONS
  Beta-hydroxy-beta-methylbutyrate supplementation contributed to preservation of muscle mass in older adults. HMB supplementation may be useful in the prevention of muscle atrophy induced by bed rest or other factors. Further studies are needed to determine the precise effects of HMB on muscle strength and physical function in older adults.
authors.affiliation: Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, Tianjin, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Wu
authors.affiliation: Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, Tianjin, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Xia
authors.affiliation: Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, Tianjin, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, Tianjin, China.
authors.forename: Huanmin
authors.initials: H
authors.lastname: Du
authors.affiliation: Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, Tianjin, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Guo
authors.affiliation: Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, Tianjin, China.
authors.forename: Xing
authors.initials: X
authors.lastname: Liu
authors.affiliation: Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, Tianjin, China.
authors.forename: Chunlei
authors.initials: C
authors.lastname: Li
authors.affiliation: Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, Tianjin, China.
authors.forename: Guowei
authors.initials: G
authors.lastname: Huang
authors.affiliation: Nutritional Epidemiology Institute and School of Public Health, Tianjin Medical University, Tianjin, China. Electronic address: nkj0809@gmail.com.
authors.forename: Kaijun
authors.initials: K
authors.lastname: Niu
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001510:Bed Rest; D001823:Body Composition / Q000187:drug effects* / Q000502:physiology; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000187:drug effects* / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D016032:Randomized Controlled Trials as Topic; D014631:Valerates / Q000008:administration & dosage*
chemical_list: D014631:Valerates; C004961:beta-hydroxyisovaleric acid
keywords: Beta-hydroxy-beta-methylbutyrate; HMB; Meta-analysis; Muscle mass; Sarcopenia