β-hydroxy-β-methylbutyrate (HMβ), Physical training and skeletal muscle: a systematic review

Abstract

Skeletal muscle mass gain is beneficial in several situations. It improves athlete's performance and quality of life in pathological situations. The existence of different methods that are able to increase muscle mass brings up discussions about nutritional supplements use on physically active individuals. β-hydroxy-β-methylbutyrate is a Leucine metabolite and it's believed to have an anticatabolic effect with different results depending on the type of exercise done. Objective: The objective of this research was to identify and categorize the methodological features and results of β-hydroxy-β-methylbutyrate (HMβ) studies, physical exercise and its effects on skeletal muscle in the last 20 years. Materials and Methods: We carried out a review in the literature using PUBMED and Medline data bases. We analyzed 19 articles from the 4587 initially found, according to the inclusion and exclusion criteria. After the selection we analyzed the date of publishing and country of origin, sample size and type, dosage used, exercise protocol and results on skeletal muscle. Results: Most of the studies came from the USA, were published between the years of 2000 and 2005. Most of the papers used only males and the main dosage used was 3.0g/day with resistance exercise, although endurance exercise and untrained individuals showed some interesting results. Data from these studies varied from increase in muscle mass and muscle strength, recovery of isokinetic and isometric muscle function, decrease in lactate dehydrogenase and proteolysis and decrease in creatine kinase. Conclusion We can conclude that although HMβ has some positive effects on untrained individuals, its effects on trained individuals still need further confirmation.