New Studies: HMB Reduces Body Fat
by: Robbie Durand
β-Hydroxy-β-methylbutyrate (HMB), a leucine derived metabolite, has been demonstrated to augment strength and lean muscle gains when supplemented in conjunction with resistance training. While HMB has displayed robust anabolic/anticatabolic properties, the underlying mechanisms regarding its efficacy are not completely understood. HMB is known to increase muscle protein synthesis through mTOR signaling pathways while concurrently reducing proteolytic processes. Recently, an 18% increase in strength gain was demonstrated following 12 weeks of HMB ingestion compared to placebo in experienced resistance trained men. Two new studies were recently published this year which suggest that HMB maybe a supplemet that you want to include in your cabinet.
Study 1: HMB Reduces Bodyfat in Older Men
The effects of 12-weeks of HMB ingestion and resistance training (RT) on abdominal adiposity were examined in 48 men (66–78 yrs). All participants were randomly assigned to 1 of 4 groups: no-training placebo, HMB only, resistance training with placebo, or HMB with resistance training. DEXA scans were used to estimate abdominal fat mass. At the end of the study, the abdominal fat in the men consuming resistance training with placebo group was significantly less than no-training placebo, HMB only, resistance training with placebo. These data suggested that HMB in combination with 12 weeks of RT decreased abdominal fat mass in elderly men.
Study 2: HMB Increases GH/IGF-1
The second study, examined the endocrine response to a bout of heavy resistance exercise following acute β-hydroxy-β-methylbutyrate free acid (HMB-FA) ingestion. Twenty resistance trained men were randomized and consumed either 1 g of HMB-FA (BetaTor) or placebo (PL) 30 min prior to performing an acute heavy resistance exercise protocol. Blood was obtained before, immediately after, and 30 min after exercise. Circulating concentrations of testosterone, growth hormone (GH), insulin-like growth factor (IGF-1), and insulin were assayed. The resistance exercise protocol resulted in significant elevations in testosterone , GH , and insulin immediately post-exercise, with GH and insulin remaining elevated 30 minutes post exercise. A significant interaction was noted between groups in the plasma GH response immediately post-exercise, which was significantly higher following HMB-FA compared to placebo . Elevations in GH and IGF-1 were significantly higher in the HMB-FA group compared to PL. Conclusion, HMB-FA prior to resistance exercise augments the GH response to high volume resistance exercise compared to placebo. These findings provide further support for the potential anabolic benefits associated with HMB supplementation.
In summary, these results appear to be the first examination suggesting that one gram of HMB-FA can promote a significantly greater postexercise increase in GH and IGF-1 compared to PL. This finding provides important contributions to our understanding of how HMB may affect endocrine function in humans.
Supplementation of HMB tends to be in the dosage range of 1-3g daily for the purpose of reducing muscle mass losses over time (anti-catabolic). As HMB is said to be 20-fold more potent than leucine for this purpose, it is seen as equivalent to 20-60g of leucine supplementation. Adding HMB maybe an important supplement to add to any athletes supplement stack.
Jeffrey R. Stout, David H. Fukuda, Kristina L Kendall, Abbie E. Smith, Ryan, Jordan R. Moon, and Jay R. Hoffman. β-hydroxy-β-methylbutyrate Supplementation and Resistance Exercise
Significantly Reduce Abdominal Adiposity in Healthy Elderly Men. Experimental Gerontology. Volume 64, April 2015, Pages 33–34
J. M. Wilson, R. P. Lowery, J. M. Joy et al., “The effects of 12 weeks of beta-hydroxy-beta-methylbutyrate free acid supplementation on muscle mass, strength, and power in resistance-trained individuals: a randomized, double-blind, placebo-controlled study,” European Journal of Applied Physiology, vol. 114, no. 6, pp. 1217–1227, 2014.
W. J. Kraemer, D. L. Hatfield, J. S. Volek et al., “Effects of amino acids supplement on physiological adaptations to resistance training,” Medicine and Science in Sports and Exercise, vol. 41, no. 5, pp. 1111–1121, 2009.
S. Nissen, R. Sharp, M. Ray et al., “Effect of leucine metabolite β-hydroxy-β-methylbutyrate on muscle metabolism during resistance-exercise training,” Journal of Applied Physiology, vol. 81, no. 5, pp. 2095–2104, 1996.
P. Gallagher, J. Carrithers, M. Godard, K. Schulze, and S. Trappe, “β-Hydroxy-β-methylbutyrate supplementation during resistance training,” Medicine & Science in Sports & Exercise, vol. 31, no. 5, p. S402, 1999.
Jeremy R. Townsend, Jay R. Hoffman, Adam M. Gonzalez, Adam R. Jajtner, Carleigh H. Boone, Edward H. Robinson, Gerald T. Mangine, Adam J. Wells, Maren S. Fragala, David H. Fukuda, and Jeffrey R. Stout. Effects of β-Hydroxy-β-methylbutyrate Free Acid Ingestion and Resistance Exercise on the Acute Endocrine Response. International Journal of Endocrinology. Volume 2015 (2015),