Ritch
28-02-2010, 06:54 PM
Another one with scientific research is HMB. Here`s some reading on it.
The HMB Controversy: If, how, and for whom it may benefit
Jacob M. Wilson, M.S., PhD Candidate, CSCS
One of the more controversial supplements in industry is Beta-hydroxy-beta methylbuytrate (HMB). I have done an extensive amount of research on HMB. In fact in my 3 years at FSU I have published two papers in the journal of Nutrition and Metabolism (Wilson, Wilson et al. 2008; Wilson 2009) on the subject, and also discussed it in a manuscript in the journal of Nutritional Biochemistry(Kim, Wilson et al. 2009)#. I have also had the opportunity to speak on the subject internationally with my brother Gabriel Wilson(Wilson and Wilson 2008). Finally in terms of laboratory experience I have completed two studies on the supplement, and am in the process of finishing two more looking at what genes HMB may regulate. Thus, the readers of natural muscle will have a unique perspective on what I feel is one of the most critical supplements for bodybuilders.
What is HMB?
After consuming a meal protein synthesis is elevated, and protein breakdown is lowered. Years of research indicate that 80 % of the stimulatory effect on protein synthesis is regulated by the protein or amino acid content in that meal. Of the 20 amino acids however, the primary one essential for this effect is the branched chain amino acid leucine(Norton and Wilson 2009). Leucine is therefore perhaps the most critical component in a bodybuilder’s diet. Even more intriguing however is that leucine appears to also lower protein breakdown. For years it was not known how this exactly occurred. What was known however was that leucine is converted to HMB. Latter scientists discovered that if this conversion is blocked then leucine’s effects on protein breakdown are inhibited. (Mitch and Clark 1984).
Only 5 % of leucine is converted to HMB, which translates to an unreasonable amount of leucine needed to be consumed in the diet to maximize HMBs effects. The efficacy of HMB supplementation has been extensively investigated in the literature. While a number of studies suggest that HMB may have the ability to promote lean mass gain and performance benefits, there are conflicting results. Enter the controversy. Subsequently we are going to show how and if HMB works for athletes, and propose possible explanations for conflicting research.
The Efficacy of HMB in Athletic Populations
In a recent publication from my brother and I(Wilson, Wilson et al. 2008), we found it necessary to divide the studies on HMB into a number of categories. This is because it is necessary to distinguish between trained and untrained individuals, as well as aerobic vs. anaerobic activities. When this is done a number of findings become clear.
The benefits of HMB in untrained athletes is well established, with only two studies (single workout studies)(Paddon-Jones D 2001; Hewitt Jennifer A 2006) in our paper showing no benefit from HMB on muscle recovery.
The real controversy centers on trained athletes. While we identified several studies in the literature supporting the efficacy of HMB in trained aerobic and weight lifting athletes, there are a number of studies which suggest otherwise.
While I certainly do not dismiss these studies, I do contend that they are limited, and more research is needed to clarify on our understanding of HMB. However prior to explaining to you exactly why I have this opinion, you need to know exactly how this supplement works.
HMB Mechanisms of Action
In a nut shell, there are three mechanisms by which HMB is purported to work (figure 1): A.) improved sarcolemma (muscle cell) integrity, B.) increased protein synthesis (building of muscle tissue), and C.) decreased muscle protein breakdown (tissue atrophy).
The most common mechanism is known as the cholesterol synthesis hypothesis. Cholesterol is an important component of the muscle cell membrane. Consequently, a damaged muscle cell, such as after exercise, may lack the ability to produce adequate cholesterol for optimal repair. Incidentally, there is evidence which suggests that HMB can be converted into the rate limiting building block for de-nova cholesterol synthesis, HMG-CoA (Nissen, Sharp et al. 2000). This should result in quicker recovery from injury.
In addition, there is recent evidence showing that HMB may inhibit the main pathway responsible for protein breakdown (Ubiquitin pathway), as well as stimulate the primary pathway responsible for muscle protein synthesis (mTOR pathway). (Baxter 2006). In short, it is suggested that HMBs protective effects will allow bodybuilders to lift heavier weights over more sets before fatiguing due to muscle damage, and they will be able to repair damage at a heightened state. This coupled with the finding that HMB increases muscle building (protein synthesis) while stopping protein breakdown make it the perfect candidate for the serious bodybuilder.
Now let’s get back to this HMB controversy in advanced lifters.
The Efficacy of HMB in Advanced Lifters Continued…
Two mechanisms by which HMB may work – protein breakdown and its ability to strengthen muscle cell integrity – suggest that HMB may only be effective when muscle damage occurs or in a situation such as calorie restriction when muscle loss is heightened. Therefore, in order to see the benefits of HMB via these mechanisms, muscle damage or heightened protein breakdown must be elicited, either by a training stimulus, or a hardcore diet. Indeed, this was supported by Dr. Nissen and colleagues (1997), who showed that HMB supplementation increased muscle mass, fat loss, and strength in lifters who did exercise, but not for those who did not exercise.
While a number of studies have shown HMB to work in advanced lifters the above reasons may explain why they do not benefit consistently from HMB, in comparison to novice lifters. You see, there is a phenomenon known as the “repeated bout effect.” Essentially, the more you train, the more resistant your muscles become to being damaged (Nosaka, Sakamoto et al. 2001). Therefore, if experienced bodybuilders and lifters are to benefit from HMB supplementation, they must commit enough muscle damage, by continually overloading their muscles and changing up their rep, and set schemes. Incidentally, our paper identified a lack of variable training in several of the routines prescribed for advanced lifters who supplemented with HMB and found no benefits(Kreider, Ferreira et al. 1999). For instance, in a previous study(Kreider, Ferreira et al. 1999) advanced weight lifters were instructed to carry out their usual training routine while supplementing with HMB. Over 4 weeks of training and HMB supplementation, neither control nor supplemented conditions increased muscle mass, or lifted heavier in any measured lifts. If the athletes had no changes in performance measures in any condition, this suggests that they were adapted to their program, and perhaps needed to include more variation to see benefits from HMB. This is partly supported by studies which do support the efficacy of HMB supplementation for advanced resistance trained athletes (Nissen SL 1996; Panton, Rathmacher et al. 2000; Nissen and Sharp 2003). For instance, Panton et al.(Panton, Rathmacher et al. 2000) showed that 4 weeks of HMB supplementation in 20-40 year old men and women, resulted in greater fat loss (-1.1% vs. -.5%), upper body strength (7.5 vs. 5.2 kg), and LBM (1.4 vs. .9 kg) than the placebo group, regardless of sex or training experience.
Secondly, if HMB operates through effecting protein turnover (protein synthesis and degradation) such changes are typically slow, and may only be manifested over a number of months of training. Currently, the experiments on HMB are typically 4-8 weeks in duration. Such a time span may not be long enough to see changes in muscle mass.
HMB and Conditions of Muscle Wasting
There are a number of studies which indicate that HMB supplementation may be advantageous during various situations of muscle wasting. This includes bed rest(J.A. 1999), limb immobilization(Soares JMC), and caloric deficits(D.D. 1997). This is important as bodybuilders often restrict their calories prior to a contest. Therefore, HMB supplementation may help slow the normal muscle loss that occurs in such situations, saving the bodybuilder from losing their density and size on stage.
The elderly are another population known to be at risk for muscle loss. Incidentally, HMB supplementation has been shown to improve body composition, strength, and functionality in this population(Vukovich, Stubbs et al. 2001).
HMB and Health
HMB has been clearly shown to be safe and may even have health benefits(Nissen, Sharp et al. 2000). No side effects have been reported in mega doses in animals(Nissen, Fuller et al. 1994), and with 3-6 grams of supplementation in humans(Gallagher, Carrithers et al. 2000).
In people with hypercholesterolemia, HMB has actually been shown to lower “bad” LDL cholesterol by a whopping 40%(Coelho C 2001)! The mechanism for this is unknown and seemingly paradoxical since HMB is thought to be converted into the rate limiting enzyme for cholesterol synthesis. Note however, that HMB has no effect on cholesterol if you have normal levels. HMB may also slightly decrease blood pressure, though this has been in part attributed to the calcium content in HMB(Nissen, Sharp et al. 2000).
Optimal Dosage of Supplementation
Currently, it is advised to take 3 grams of HMB, spread into 1 gram doses over the day. However, only two studies have investigated this(Kreider, Ferreira et al. 1999; Gallagher, Carrithers et al. 2000). We propose that more research is needed on the optimal dosage and frequency of HMB supplementation, particularly under differing stages of muscle catabolism.
The Timing of HMB (When Should I take it?)
My colleagues and I recently completed a study looking at what the optimal time was to use HMB(Wilson 2009). Prior to our research all studies had given HMB for a period of 2 weeks or greater, but no one had investigated whether taking HMB on the day of exercise actually had any benefit. We therefore sought to investigate this question. To do so we took individuals and had them perform 60 maximal eccentric contractions on a biodex on one of their legs. We measured a number of markers of damage such as serum levels of creatine kinase, and lactate dehydrogenase. These are enzymes which leak out into the blood from the muscle when it is damaged. We gave 3 grams of HMB 45 minutes before exercise or immediately after, or we gave them a placebo. We found that one marker of muscle damage (lactate dehydrogenase) didn’t even significantly rise when HMB was taken before exercise. However this marker of muscle damage increased similarly in the placebo and post HMB condition. Taking HMB before exercise also had a trend to lower muscle soreness. This suggests that taking HMB before exercise allows muscle damage to be repaired to a much greater extent. It also leads me to suggest to you that taking HMB 45 minutes prior to exercise appears to be efficacious.
HMB Practical Applications
Based on the current research, I feel confident advising HMB supplementation to novice bodybuilders and lifters. This supplement should enhance recovery, improve body composition, and strength.
For experienced bodybuilders, it is situation dependent. I believe that if you are to receive benefits from HMB, than you will have to create enough muscle damage by continually instituting new workouts and or lifting heavier weights. Or you will need to be in a situation where you are in a caloric deficit, such as when you are dieting or doing excessive cardio.
Thirdly, our research suggests that HMB may be most beneficial when taken prior to exercise (45 minutes).
Lastly, HMB appears to be safe and may even have health benefits. If you have high cholesterol, then studies suggest HMB will help you lower your LDL cholesterol back to normal levels. HMB may also lower blood pressure, though this effect may be mediated through the inclusion of calcium in HMB products.
Conclusion
HMB is one of the more misunderstood supplements on the market fluctuating in its popularity. However, given the right situation this can be a powerful tool in your arsenal to getting huge and shredded. Now if you will excuse me, it’s about 45 minutes before a leg workout and I need to take my HMB.
Yours in sport
Jacob Wilson, M.S., PhD. Candidate, CSCS
Contact information
Jacob Wilson: jmw06x@fsu.edu
About Author
Jacob Wilson is a skeletal muscle physiologist and certified strength and conditioning specialist (CSCS) with degrees in sports nutrition (B.S. Hons), and exercise physiology (M.S.). Jacob is in the final year towards obtaining his PhD. and conducts research in the Florida State University Skeletal Muscle Physiology Laboratory. He has published in numerous scientific / peer reviewed journals and spoken nationally and internationally in diverse areas of biochemistry, nutrition and metabolism, and skeletal muscle physiology. Jacob is also president and co-founder of abcbodybuilding.com
References
Baxter , J. H., Mukerji , Pradip, Voss , Anne C, Tisdale , Michael J, Wheeler , Keith B: (2006). "Attenuating Protein Degradation and Enhancing Protein Synthesis in Skeletal Muscle in Stressed Animal Model Systems." Medicine & Science in Sports & Exercise 38(5): S550-S551.
Coelho C, C. (2001). "Effects of hmb supplementation on ldlcholesterol, strength and body composition of patients with hypercholesterolemia. ." Medicine & Science in Sports & Exercise. 33(5): 340.
D.D., C. (1997). "The effect of β-hydroxy-β-methylbutyrate (HMB) and resistance training on changes in body composition during positive and negative energy balance - a randomized double-blind study."
Gallagher, P. M., J. A. Carrithers, et al. (2000). "Beta-hydroxy-beta-methylbutyrate ingestion, Part I: effects on strength and fat free mass." Med Sci Sports Exerc 32(12): 2109-15.
Gallagher, P. M., J. A. Carrithers, et al. (2000). "Beta-hydroxy-beta-methylbutyrate ingestion, part II: effects on hematology, hepatic and renal function." Med Sci Sports Exerc 32(12): 2116-9.
Hewitt Jennifer A, D. N., Glyn Howatson, van Someren , Ken A, Whyte , Gregory P: (2006). "HMB and KIC Supplementation Does Not Reduce Signs and Symptoms of Exercise-Induced Muscle Damage." Medicine & Science in Sports & Exercise 38(5): S401.
J.A., R. (1999). "Effect of the leucine metabolite β-hydroxy-β-methylbutyrate on muscle protein synthesis during prolonged bedrest. ." FASEB J 13: A1025.
Kim, J.-S., J. M. Wilson, et al. (2009). "Dietary implications on mechanisms of sarcopenia: roles of protein, 3 amino acids and antioxidants." Journal of Nutritional Biochemistry: 1-13.
Kreider, R. B., M. Ferreira, et al. (1999). "Effects of calcium beta-hydroxy-beta-methylbutyrate (HMB) supplementation during resistance-training on markers of catabolism, body composition and strength." Int J Sports Med 20(8): 503-9.
Mitch, W. E. and A. S. Clark (1984). "Specificity of the effects of leucine and its metabolites on protein degradation in skeletal muscle." Biochem J 222(3): 579-86.
Nissen, S., J. C. Fuller, Jr., et al. (1994). "The effect of beta-hydroxy-beta-methylbutyrate on growth, mortality, and carcass qualities of broiler chickens." Poult Sci 73(1): 137-55.
Nissen, S., R. L. Sharp, et al. (2000). "beta-hydroxy-beta-methylbutyrate (HMB) supplementation in humans is safe and may decrease cardiovascular risk factors." J Nutr 130(8): 1937-45.
Nissen SL, P. L., Wilhelm R, Fuller JC. (1996). "Effect of β-hydroxy-β-methylbutyrate (HMB) supplementation on strength and body composition of trained and untrained males undergoing intense resistance training." FASEB J 10: 287.
Nissen, S. L. and R. L. Sharp (2003). "Effect of dietary supplements on lean mass and strength gains with resistance exercise: a meta-analysis." J Appl Physiol 94(2): 651-9.
Norton, L. and G. J. Wilson (2009). "Optimal protein intake to maximize muscle protein synthesis." AgroFood industry hi-tech 2: 54-67.
Nosaka, K., K. Sakamoto, et al. (2001). "The repeated bout effect of reduced-load eccentric exercise on elbow flexor muscle damage." Eur J Appl Physiol 85(1-2): 34-40.
Paddon-Jones D, K. A., Jenkins D. (2001). "Short-term beta-hydroxybeta-methylbutyrate supplementation does not reduce symptoms of eccentric muscle damage. ." Int J Sport Nutr Exerc Metab. 11(4): 442-450.
Panton, L. B., J. A. Rathmacher, et al. (2000). "Nutritional supplementation of the leucine metabolite beta-hydroxy-beta-methylbutyrate (hmb) during resistance training." Nutrition 16(9): 734-9.
Soares JMC, P. S., Neuparth MJ, Duarte JA. "The effects of betahydroxy-beta-methylbuturate (HMB) on muscle atrophy induced by immobilization." Medicine & Science in Sports & Exercise 33(5): 140.
Vukovich, M. D., N. B. Stubbs, et al. (2001). "Body composition in 70-year-old adults responds to dietary beta-hydroxy-beta-methylbutyrate similarly to that of young adults." J Nutr 131(7): 2049-52.
Wilson, G. J. and J. M. Wilson (2008). "HMB Current and Future Directions." The International Society of Sports Nutrition Annual Conference 4: Supp.
Wilson, G. J., J. M. Wilson, et al. (2008). "Effects of beta-hydroxy-beta-methylbutyrate (HMB) on exercise performance and body composition across varying levels of age, sex, and training experience: A review." Nutr Metab (Lond) 5: 1.
Wilson, J. M. K., J-S., Lee, S-R., Rathmacher, J.A., Dalmau, B., Kingsley, J.D., Koch, H., Manninen, A.M., Panton, L.B. (2009). "Acute and timing effects of beta-hydroxy-beta-methylbutyrate (HMB) on indirect markers of skeletal muscle damage." Nutrition and Metabolism 6:6.
Powered by vBulletin® Version 4.2.1 Copyright © 2026 vBulletin Solutions, Inc. All rights reserved.