title: HMB supplementation: clinical and athletic performance-related effects and mechanisms of action.
abstract: Amino acids such as leucine and its metabolite α-ketoisocaproate (KIC), are returning to be the focus of studies, mainly because of their anti-catabolic properties, through inhibition of muscle proteolysis and enhancement of protein synthesis. It is clear that these effects may counteract catabolic conditions, as well as enhance skeletal muscle mass and strength in athletes. Moreover, beta-hydroxy-beta-methylbutyrate (HMB) has been shown to produce an important effect in reducing muscle damage induced by mechanical stimuli of skeletal muscle. This review aims to describe the general scientific evidence of KIC and HMB supplementation clinical relevance, as well as their effects (e.g., increases in skeletal muscle mass and/or strength), associated with resistance training or other sports. Moreover, the possible mechanisms of cell signaling regulation leading to increases and/or sparing (during catabolic conditions) of skeletal muscle mass are discussed in detail based on the recent literature.
authors.affiliation: Laboratory of Applied Nutrition and Metabolism, Physical Education and Sports School, University of Sao Paulo, São Paulo, Brazil. neloz@ig.com.br
authors.forename: Nelo Eidy
authors.initials: NE
authors.lastname: Zanchi
authors.forename: Frederico
authors.initials: F
authors.lastname: Gerlinger-Romero
authors.forename: Lucas
authors.initials: L
authors.lastname: Guimarães-Ferreira
authors.forename: Mário Alves
authors.initials: MA
authors.lastname: de Siqueira Filho
authors.forename: Vitor
authors.initials: V
authors.lastname: Felitti
authors.forename: Fabio Santos
authors.initials: FS
authors.lastname: Lira
authors.forename: Marília
authors.initials: M
authors.lastname: Seelaender
authors.forename: Antonio Herbert
authors.initials: AH
authors.lastname: Lancha
mesh_terms: D000284:Administration, Oral; D000328:Adult; D054874:Athletic Performance; D001823:Body Composition; D019587:Dietary Supplements; D006801:Humans; D007651:Keto Acids / Q000008:administration & dosage* / Q000378:metabolism; D007930:Leucine / Q000008:administration & dosage* / Q000378:metabolism; D008297:Male; D053580:Muscle Strength / Q000187:drug effects* / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D055070:Resistance Training; D015398:Signal Transduction / Q000187:drug effects; D014631:Valerates / Q000008:administration & dosage* / Q000378:metabolism
chemical_list: D007651:Keto Acids; D014631:Valerates; C004961:beta-hydroxyisovaleric acid; C013082:alpha-ketoisocaproic acid; D007930:Leucine