Nutr Hosp. 2015;32(1):20-33 ISSN 0212-1611 • CODEN NUHOEQ S.V.R. 318 Revisión Usefulness of β-hydroxy-β-methylbutyrate (HMB) supplementation in different sports: an update and practical implications Francisco J. Albert1, Jaime Morente-Sánchez2, Francisco B. Ortega2, Manuel J. Castillo1 and Ángel Gutiérrez1 1Department of Medical Physiology, Faculty of Medicine, University of Granada. 2Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Spain. Abstract EFICACIA DE LA SUPLEMENTACIÓN CON β-HYDROXY-β-METHYLBUTYRATE (HMB) β β Introduction: although -hydroxy- -methylbutyrate EN EL DEPORTE: ACTUALIZACIÓN E (HMB) is generally marketed as a supplement for increa- IMPLICACIÓN PRÁCTICA sing muscle mass and strength, it is still not fully unders- tood how and in which particular sports and conditions HMB can be more effective. Resumen Aims: the primary purpose of this review is to update Introducción: aunque el β-hidroxi-β-metilbutirato and summarize the current knowledge about the useful- (HMB) se ha empleado generalmente como suplemento ness of HMB and to organize this information by diffe- para aumentar la masa muscular y la fuerza, es necesario rent sports with specific reference to sports with high un mejor entendimiento de su función y averiguar en qué wear and tear phenomena as soccer, rugby or football. deportes es más efectivo. Methods: a search was performed in PubMed databa- Objetivos: el objetivo principal de esta revisión es ac- se. This review presents the results about HMB use in tualizar y resumir el conocimiento existente en torno a la sport. utilización del HMB para clasificarla en función de cada Results: the articles identified in this review support modalidad deportiva, con especial mención a aquellas the notion that HMB could help to attenuate tissue cata- actividades con un alto grado de destrucción muscular, bolism and initiate muscle anabolism particularly in un- como pueden ser el fútbol, el rugby o el fútbol americano. trained individuals exposed to strenuous exercise or when Métodos: se utilizó la base de datos PubMed para la trained individual are exposed to periods of high physical búsqueda de artículos. Esta revisión presenta los resul- stress. HMB could therefore be applied in some specific tados sobre la utilización de HMB clasificados por de- periods of athlete’s season where there are high-intensity portes. training periods, high density of competitions and little Resultados: la mayoría de los artículos seleccionados recovery time between them, starting recovery phases sugieren que cuando una persona entrenada o no entre- from an injury period and/or any other different situa- nada se somete a un ejercicio intenso o diferente al ha- tion where performance or recovery could be affected by bitual, el HMB puede atenuar el catabolismo muscular a great catabolic environment. producido e iniciar los procesos anabólicos necesarios Conclusion: this update contributes to clarify and de- para recuperar lo antes posible. De esta forma, el HMB fine possible mechanisms and/or effectiveness of HMB podría aplicarse en algunos momentos concretos de la supplementation related to endurance sports (i.e. cycling temporada deportiva en los que hubiera períodos con and athletics), strength-power sports (i.e. resistance trai- entrenamientos de alta intensidad, o durante un periodo ning, football, rugby, soccer, judo, waterpolo and rowing) con alta densidad competitiva y con poca recuperación and recreational activities. entre competiciones, o bien durante las primeras fases (Nutr Hosp. 2015;32:20-33) de la readaptación física después de una lesión y/o du- rante cualquier otra situación en la que el rendimiento o DOI:10.3305/nh.2015.32.1.9101 la recuperación se pueden ver afectados por un entorno Key words: HMB. Recovery. DOMS. Signalling-molecu- altamente catabólico. le. mTOR. Conclusión: esta revisión pretende aclarar y definir los posibles mecanismos por los que la suplementación con HMB puede ser efectiva en deportes de resistencia (ciclismo y carreras de fondo), en deportes de fuerza-po- tencia (fútbol, yudo, waterpolo, remo, fútbol americano y Correspondence: Francisco J. Albert García. musculación) y en actividades deportivas recreacionales. Department of Physiology. Faculty of Medicine. (Nutr Hosp. 2015;32:20-33) University of Granada. Av. de Madrid s/n. 18012 Granada, Spain. DOI:10.3305/nh.2015.32.1.9101 E-mail: [email protected] Palabras clave: HMB. Recuperación. DOMS. Molécula de Recibido: 10-IV-2015. señalización. mTOR. Aceptado: 24-IV-2015. 20 005_9101 Eficacia de la suplementacion.indd 20 16/06/15 19:47 Abbreviations and supply of adequate nutrients. Essential nutrients are particularly important. The branched chain amino 3-MH: 3-methylhistidine. acids (BCAAs) leucine, isoleucine and valine have AMPK: Adenosine monophosphate protein kinase. been widely studied in this context1. Leucine has BCAAs: Branched chain amino acids. important roles in protein metabolism2-4, glucose ho- Ca-HMB: β-hydroxy-β-methylbutyrate Calcium Salt. meostasis5, insulin action6. Leucine has anti-catabolic CD: Cool Down. properties7 and facilitates recovery from exercise8,9. CK: Creatine Kinase. In 1996, it was suggested that a plausible candidate Cr: Creatine. responsible for these effects could be its intracellular CHO: Carbohydrate. derived metabolite β-hydroxy-β-methylbutyrate wi- CRP: C-reactive protein. dely known as HMB10, which is endogenously produ- CWI: Cold Water Immersion. ced in animals and humans11. The first step in HMB DOMS: Delayed onset muscle soreness. production is the reversible transamination of leucine F: Female. to α-ketoisocaproate (KIC) by the enzyme branched FM: Fat Mass. chain amino acid transferase12. Then, KIC is either FML: Fat Mass Lost. metabolized into isovaleryl-CoA in the mitochondria, FFM: Fat Free Mass. by the enzyme α-ketoacid dehydrogenase, or into GH: Growth hormone. HMB in the cytosol, by the enzyme alpha-ketoisoca- H: Hamstring. proate dioxygenase12. KIC is mainly metabolized into HMB: β-hydroxy-β-methylbutyrate. isovaleryl-CoA, with only some 5% of leucine being HMB-FA: β-hydroxy-β-methylbutyrate-Free Acid. converted into HMB. Isovaleryl-CoA is further me- HMG-CoA: β-hydroxy-methylglutaryl-CoA. tabolized to beta-methyl crotonyl-CoA and then to IGF-1: Insulin-like growth factor. beta-methyl gluconyl-CoA and β-hydroxy-methylglu- KIC: Ketoisocaproic Acid. taryl-CoA (HMG-CoA). Similarly, HMB can also be LBM: Lean Body Mass. converted to beta-hydroxy-methylbutyrate-CoA and LDH: Lactate Dehydrogenase. then to HMG-CoA. HMG-CoA is a precursor in cho- M: Male. lesterol synthesis or alternatively can be degraded to MAPK/ERK: Mitogen activated protein kinase / ex- Acetoacetyl-CoA, acetyl CoA and acetoacetate, a ke- tracellular signal regulated kinase. tone body. MAS: Running speed during an incremental test at Consequently, as precursor of cholesterol it may which VO2max. is attained. have structural functions by its incorporation to cell MCV: Maximal Voluntary Contraction. membranes and through acetyl CoA or ketone body N: No. may serve as an energy substrate. NE: No Effect. Empirically, HMB has been classically proposed NR: Not Reported. and is widely used as a nutritional supplement to limit Q: Quadriceps. muscle damage during exercise and to increase mus- OBLA: Onset of Blood Lactate Accumulation. cle gain after strenuous exercise or hard training. The PI3K/Akt: Phosphoinositide 3-kinase / Protein ki- effectiveness of HMB supplementation needs further nase B. clarification into how to optimize its administration PRS: Perceived Recovery Scale. (dosage and timing) and better specify in which parti- RCP: Respiratory Compensation Point. cular conditions its use is recommended and effective. Sirt1: Silent information regulation transcripts. A dose of 3g/day of HMB produces better results on Tac: Tactical exercises. performance markers and has potential health benefits. Tec: Technical exercises. Since HMB is a metabolite of leucine, the question is TNFa: Tumor Necrosis Factor Alpha. why not simply taking proteins, BCAA or leucine ins- TNFR1: Tumor Necrosis Factor Receptor 1. tead of its metabolite. To put this into perspective, a V: Velocity. subject would need to consume over 600 g of high qua- VO2peak: Peak oxygen consumption. lity protein to obtain the amount of leucine (60 grams) VT: Ventilatory Threshold. necessary to produce the typical 3 g daily dosage of WU: Warm-Up. HMB used in human studies13. Since consumption of Y: Yes. this amount of protein is not realistic and perhaps not even healthy either, HMB is typically administered via dietary supplementation14. Introduction In athletic context, a number of studies during the last 15 years have indicated that HMB supplementa- Limiting the wear and tear process while exercising tion may elicit several ergogenic benefits, including and adequate recovery afterwards is fundamental for better recovery15,16, increased strength17-19, increased preserving athletes’ health and their optimal perfor- lean body mass (LBM)20, decreased body fat3, increa- mance. The two key components of recovery are rest sed power21,22 and improvements in aerobic23,24 and Usefulness of β-hydroxy-β-methylbutyrate Nutr Hosp. 2015;32(1):20-33 21 (HMB) supplementation in different sports: an update and practical implications 005_9101 Eficacia de la suplementacion.indd 21 16/06/15 19:47 anaerobic25 performance. Moreover, HMB supplemen- mage, restoration of muscle functionality, attenuation tation has been used as a potential strategy