β-Hydroxy-β-Methylbutyrate (HMB)

β-Hydroxy-β-Methylbutyrate (HMB)

Provide a general overview of HMB intake and metabolism
Educational Objectives for the β-Hydroxy-β-Methylbutyrate (HMB) Presentation Provide a general overview of HMB intake and metabolism Describe mechanistic studies of the roles of HMB in cell signaling pathways governing both muscle protein synthesis and degradation Discuss role of HMB in reducing muscle damage during exercise Review clinical data evaluating changes in body composition and performance in athletes receiving HMB supplementation Used alone and in combination with creatine or other amino acids Including effects in healthy, older adults Present other therapeutic and medical applications Address the safety of HMB supplementation

General overview of intake and metabolism

Ca++ HO O– O –O OH What Is HMB? HMB is a leucine metabolite
Leucine is an essential branched-chain amino acid that can trigger muscle protein synthesis and may inhibit protein degradation1 Is it unknown whether leucine or its metabolites actively participate in protein synthesis/degradation Leucine is transaminated to α-ketoisocaproate (KIC) by branched-chain amino acid transferase, mainly in muscle tissues Approximately 5% to 10% of α-ketoisocaproate (KIC) is converted to HMB (by KIC-dioxygenase) in the cell cytosol Calcium HMB has the following molecular structural formula2 Ca++ HO O– O –O OH Nemet D, et al. IMAJ. 2005;7: Available at: Accessed May 10, 2011.

Formation of HMB During Leucine Metabolism
KIC Isovaleryl-CoA β-methyl-crotonyl-CoA (MC-CoA) β-hydroxy-β-methylbutyrate (HMB) HMB-CoA HMG-CoA Mevalonate Acetyl-CoA Cholesterol (5-10% of Leu metabolism) Acetoacetyl-CoA (only when biotin is deficient) Adapted with permission from Nissen SL and Abumrad NN. J Nutr Biochem. 1997;8(6):

Sources of HMB in the Diet
Catabolism of leucine Mean intake of leucine from food and supplements ( NHANES III) was 6.1 g/day1 Assuming 5% to 10% conversion in the body, this represents 0.3 to 0.6 g HMB per day To get the 3-g HMB dose typically used in research, g leucine/day would have to be consumed HMB in foods There are traces of HMB in many animal- and plant-based foods, especially catfish and alfalfa2 Institute of Medicine of the National Academies. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press; 2005:1008. Available at: Accessed May 10, 2011.

HMB Absorption and Kinetics
The mechanism of HMB absorption from the intestine has not been reported In 2 kinetic trials, plasma half-life was 2.5 hours HMB levels return to baseline at ~ 9 hours after ingestion Up to 30% of an oral HMB dose is excreted unchanged in the urine The addition of glucose to a calcium HMB supplement does not increase bioavailability or cellular uptake of HMB Added glucose does slow HMB absorption through delayed gastric emptying Vukovich MD, et al. J Nutr Biochem. 2001;12(11):

HMB Bioavailability Bioavailability of a free acid gel form was greater vs calcium HMB capsules 2 studies, each with 8 healthy adults (4 male, 4 female) 3 treatments 1 g calcium HMB in capsule form Equivalent amount of HMB in free acid form in a gel (swallowed immediately) Free acid HMB gel held sublingually for 15 sec, then swallowed Blood and urinary HMB levels were monitored for 3 to 24 hours after ingestion Only commercially available form is calcium salt c b a 300 250 200 150 100 50 400 600 800 1000 1200 1400 Time, min HMB, μmol/l plasma Calcium HMB capsules Free acid HMB gel conditions a P < .05 bP < .01 cP < .0001 Reprinted from Fuller JC Jr, et al. Br J Nutr. 2011;105:

Mechanisms of action

Possible HMB Mechanisms of Action
HMB may be an anticatabolic agent Studies have documented potentially inhibited pathways such as the ubiquitin-proteasome pathway in a murine model1,2 HMB may be a substrate for cholesterol synthesis in muscle3 Formation of 3-hydroxy-3-methylglutaryl Coenzyme A (HMG-CoA, precursor for cholesterol synthesis) Muscle is dependent on cholesterol synthesis to meet its needs Increased cell membrane integrity with improved muscle cholesterol synthesis Stressed or injured muscle cells might not synthesize enough cholesterol HMB also helps to stimulate protein synthesis via the mTOR pathway4 May be the real factor by which leucine stimulates protein synthesis HMB may have other effects (eg, immunomodulatory or hormonal)5 Lecker SH, et al. J Nutr. 1999;129:227S-237S. Smith HJ, et al. Cancer Res. 2005;65: Nissen SL and Abumrad NN. J Nutr Biochem. 1997;8: Eley HL, et al. Am J Physiol Endocrinol Metab. 2008;295:E1409-E1416. Zanchi NE, et al. Amino Acids. 2011;40(4):

The Ubiquitin-Proteasome Pathway for Protein Degradation
Reprinted from Lecker SH, et al. J Nutr. 1999;129:227S-237S.

Effects of HMB on the Ubiquitin-Proteasome Pathway
Study performed in tumor-bearing (MAC16) mice that were treated for 3 days with Olive oil/phosphate-buffered saline (control) β-hydroxy-β-methylbutyrate (HMB) Eicosapentaenoic acid (EPA) HMB and EPA Chymotrypsin-like enzyme activity (indicator of ubiquitin proteasome pathway) in the gastrocnemius muscle was assessed 20 18 16 14 12 Fluorescent units/h/gram 10 a a a 8 6 4 2 Control 0.25 g/kg HMB 0.6 g/kg EPA HMB + EPA a P < .005 Reprinted from Smith HJ, et al. Cancer Res. 2005;65:

Effects of HMB on Protein Synthesis and Degradation
Initiator (PIF, LPS, TNF-, angiotensin II, etc.) X HMB blocks pathway here Caspase-8 Caspase-3 PKR NF- (nuclear accumulation) p38 MAPK ROS PKR P Proteasome + E3 mRNA eIF2 P eIF2 Translational efficiency Protein degradation Protein synthesis PIF, proteolysis-inducing factor; LPS, lipopolysaccharide; TNF, tumor necrosis factor; PKR, RNA-dependent protein kinase; MAPK, mitrogen-activated protein kinase; NF, nuclear factor; ROS, reactive oxygen species; eIF, eukaryotic initiation factor; P, phosphorylated. Based on Eley HL, et al. Am J Physiol Endocrinol Metab. 2008;295:E1417-E1426.

Further Effects of HMB on Cellular Protein Synthesis
HMB increases mTOR signaling pathway activity mTOR increases protein translation Promotes it Keeps it from being turned off Eley HL, et al. Am J Physiol Endocrinol Metab. 2008;295:E1409-E1416. Adapted from SABiosciences, a QIAGEN company. Available at: Accessed June 27, 2011.

Densitometry units, ph/tot Densitometry units, ph/tot
Effects of HMB on Phosphorylation Status of mTOR Pathway Signaling Factors HMB increased phosphorylation of mTOR signaling factors, stimulating protein synthesis HMB attenuates the depressive effects of proteolysis-inducing factor on protein synthesis p mTOR Total mTOR 0.9 0.8 a 0.7 0.6 Densitometry units, ph/tot 0.5 0.4 0.3 0.2 0.1 -2 -1 2 Time, h p P70S6K Total P70S6K 1.6 b 1.4 1.2 1.0 Densitometry units, ph/tot 0.8 0.6 0.4 0.2 -2 -1 2 Time, h HMB (50 M) added here to murine myotubes. aDifferent from control, P < .05 bDifferent from control, P < .01 Abbreviations: mTOR, mammalian target of rapamycin; p, phosphorylation; P70S6k, 70-kDa ribosomal S6 kinase. Reprinted from Eley HL, et al. Am J Physiol Endocrinol Metab. 2007;293:E923-E931.

HMB and indicators of muscle damage

Exercise can result in muscle cell membrane disruption1,2
Evidence for a Protective Effect of HMB Against Muscle Cell Membrane Disruption Exercise can result in muscle cell membrane disruption1,2 Elevations of creatine kinase (CK) and other enzyme (eg, lactate dehydrogenase [LDH]) levels in the blood can be indicators of muscle cell membrane disruption3,4 Not necessarily muscle protein breakdown A few exercise studies have found a blunted CK response during HMB supplementation5,6 McBride JM, et al. Med Sci Sports Exerc. 1998;30(1):67-72. Hurley BF, et al. Int J Sports Med. 1995;16(6): Cabaniss CD. In: Walker HK, Hall WD, Hurst JW, eds. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; 1990: Chapter 32. Sarri E, et al. Biochem J. 2006;394(pt 1): Knitter AE, et al. J Appl Physiol. 2000;89: van Someren KA, et al. Int J Sport Nutr Exerc Metab. 2005;15(4):

Effect of HMB Supplementation on Creatine Kinase Levels During Exercise
Study involving 13 participants (5 male, 8 female) that had a history of running at least 48 km/wk Participants received 3 g HMB or placebo daily for 6 weeks before a prolonged run (double-blind) Pair-matched based on best 2-mile run time The run was 20 km on a collegiate cross-country course CK and LDH were measured 2 weeks before the run (Pre), immediately after the run (Post), and at 1, 2, 3, and 4 days after the run Results follow on next slide Knitter AE, et al. J Appl Physiol. 2000;89:

Time relative to the prolonged run
Effect of HMB Supplementation on Creatine Kinase Levels During Exercise (Cont’d) Main effect for treatment in CK measurement, P = .05, with no significant group × time interaction A significant main effect for treatment in LDH measurement (P = .003), with no significant group × time interaction 450 Placebo HMB 400 350 300 250 CPK activity, U/L 200 150 100 50 Pre Post 1d Post 2d Post 3d Post 4d Post Time relative to the prolonged run Reprinted from Knitter AE, et al. J Appl Physiol. 2000;89:

Effects of HMB Supplementation on Muscle Damage During Exercise
1 study showed positive effects of 3 g HMB and 0.3 g KIC/day versus placebo when received for 2 weeks prior to exercise (biceps curl with prolonged eccentric phase)1 In 6 nonresistance-trained male subjects Supplementation reduced the delayed onset of muscle soreness (DOMS) ratings (P < .05) Blunted CK response and decrement of 1-repetition maximum Several studies did not show any effects of HMB on muscle damage2-5 However, a major difference between the positive HMB studies and the studies without any effect is the length of supplementation Ranged from a single acute HMB administration (3 g) before or after exercise to 11 days of supplementation (3 g/day) before exercise In addition, 1 study showing no effects of HMB/KIC supplementation on muscle damage involved intensive exercise (40 minutes of downhill running)4 Any supplementation may not reduce that level of muscle damage Although not significant, a trend was observed toward more rapid recovery of muscle function with HMB/KIC supplementation van Someren KA, et al. Int J Sport Nutr Exerc Metab. 2005;15(4): Wilson JM, et al. Nutr Metab (Lond). 2009;6:6. DOI: / Paddon-Jones D, et al. Int J Sport Nutr Exerc Metab. 2001;11(4): Nunan D, et al. J Strength Cond Res. 2010;24(2): Hoffman JR, et al. J Strength Cond Res. 2004;18(4):

Effects of HMB on body composition and strength

Historical Background on HMB Supplementation
Numerous studies of HMB supplementation in several animal models (steers, lambs, rats, chickens, trout, and horses) showed positive effects on Carcass quality, protein metabolism, immune response, muscle damage, antioxidant status, and blood lipid profile Dr. Steve Nissen (Animal Science, Iowa State University) is essentially the “father” of the HMB story Performed initial human studies of HMB supplementation in the 1990s1 Also performed a meta-analysis of supplementation studies in 2003 with respect to effects on lean body mass and strength gains2 Nissen S, et al. J Appl Physiol. 1996;81(5): Nissen SL and Sharp RL. J Appl Physiol. 2003;94:

Change in total body strength, kg
Change in Overall Muscle Strength During HMB Supplementation: Initial Study 41 healthy young adults (19-29 years), untrained 2 protein levels: 117 g/day (control) or 175 g/day Diet was controlled, nutrient powder in a shake 3 HMB supplementation doses randomized and blinded within each protein group 0, 1.5, or 3.0 g/day Mixed in orange juice Weight training for 1.5 hours 3 days/week for 3 weeks Data from control and high protein groups were pooled because there was no difference in HMB results Overall muscle strength increased at 3 weeks 8% in control group 13% in 1.5 g HMB group 18% in 3.0 g HMB group 800 Control 1.5 g HMB 3.0 g HMB b b 600 c 400 Change in total body strength, kg a 200 -200 Week 1 Week 3 aP < .03 bP < .02 cP < .01 Reprinted from Nissen S, et al. J Appl Physiol. 1996;81(5):

% Change in 3-MH from basal
Change in Urinary 3-Methylhistidine (3-MH) Excretion During HMB Supplementation: Initial Study 3-MH is a muscle-specific amino acid Formed during breakdown of muscle proteins (actin and myosin) Excreted unchanged in urine HMB supplementation reduced the physiologic increase in 3-MH during exercise Total muscle breakdown per day increased from 3% at baseline to 6% at week 3 in control group 5.5% at week 3 in 1.5 g HMB group 4.5% at week 3 in 3.0 g HMB group 100 Control 1.5 g HMB 3.0 g HMB 80 a 60 % Change in 3-MH from basal 40 b 20 aP < .04 bP < .001 -20 Week 1 Week 2 Week 3 Reprinted from Nissen S, et al. J Appl Physiol. 1996;81(5): Elia M, et al. Br Med J. 1981;282:

Change in Fat-Free Mass During HMB Supplementation: Study 2
32 healthy adults (19-22 years; mean body weight, 99 kg), almost all engaged in an exercise program before study entry and ate at university training table Randomized to placebo or 3 g HMB per day for 7 weeks HMB provided in a nutrient/protein powder; placebo was isocaloric orange juice Participants ate normal diet (no strict dietary control) Daily protein intake was estimated at 200 g (HMB) vs 180 g (placebo) Participants lifted weights 2 to 3 hours/day, 6 days/week Total body electrical conductivity (TOBEC) was used for body composition analysis HMB supplementation increased fat-free mass early in exercise regimen compared with placebo Significant gains continued through day 39 a a a 3.50 a 2.50 1.50 Fat-free mass gain, kg 0.50 -0.50 Placebo HMB + nutrient powder -1.50 10 20 30 40 50 Day of study aP < .05 Reprinted from Nissen S, et al. J Appl Physiol. 1996;81(5):

Positive Effects of HMB Supplementation on Strength, Power, and/or Body Composition
Study Design Treatment Training Results Double-blind in untrained college men, N = 371 0, 38, or 76 mg/kg/day HMB (equivalent to 0, 3, or 6 g/day) for 8 wks Resistance, 3 times/wk (80% 1-RM) assessed every 2 wks Compared with other 2 groups, Fat-free mass increased in the 38 mg/kg dose group (P < .05 for both) Peak isometric torque (knee extensor) increase in 38 mg/kg dose group (P < .05) Plasma creatine kinase (CK) 48 hours after exercise was higher in 0 mg/kg (P < .05) No difference between the 38 and 76 mg/kg dose groups Randomized in trained or untrained adults (men, 39; women, 36; age, year), N = 752 3 g/day HMB or placebo for 4 wks Strength, 3 times/wk (90% 1-RM) Compared with placebo group, the HMB group had Greater increase in upper body strength (P = .008) Blunted postexercise rise in creatine kinase vs placebo Somewhat greater increase in fat-free mass (P = 0.08) Randomized, double-blind in resistance-trained men (young adults), N = 223 3 g/day HMB or placebo for 9 wks Strength, 3 times/wk (1-RM) Significantly increased leg extension strength (~14% vs ~5% for placebo; P = .05) Similar upper body strength (bench press, biceps curls) Small, but positive, changes in body composition Randomized, double-blind in elite, national-team level, adolescent volleyball players (men, 14; women, 14), N = 284 3 g/day HMB or placebo for first 7 wks of the training season Volleyball skills (20%), power and speed drills (25%), interval (25%), endurance (15%) and resistance (circuit-style; 15%), hr/wk Increased bench press and leg press strength (6-RM; P < .05) Increased peak and mean anaerobic power (Wingate test; P < .01) Increased some measures of knee flexion isokinetic force No effects of HMB on aerobic capacity or anabolic and catabolic hormones Abbreviations: RM, repetition maximum. 1. Gallagher PM, et al. Med Sci Sports Exerc. 2000;32(12): Panton LB, et al. Nutrition. 2000;16(9): Thomson JS, et al. J Strength Cond Res. 2009;23(3): Portal S, et al. Eur J Appl Physiol. 2011;Feb 16:E-pub. 26

Studies Showing No Effects of HMB Supplementation on Strength and Body Composition
Study Design Treatment Training Results Randomized, double-blind in experienced (5.5 years), resistance-trained athletes, N = 401 0, 3, or 6 g/day HMB for 28 days in a carbohydrate/protein powder Maintained individualized resistance training program (~7 hrs/wk) and kept training logs Neither dose of HMB influenced Strength (1-RM) Body composition (by dual energy X-ray absorptiometer) Body anabolic/catabolic status Blood chemistries Randomized, double-blind in national-level athletes (polo, 17; rowers, 10) with ≥ 2 years of resistance training, N = 272 3 g/day HMB (timed-release or standard capsule) or placebo for 6 wks Resistance, 2-3 times/wk (Pre-competition phase of training) Strength Body composition Creatine kinase levels Trend toward higher creatine kinase level in placebo group (P = .07 for group x time interaction) Randomized, crossover in collegiate football players, N = 353 3 g/day HMB or placebo for 4 wks (16 players got HMB first, 19 got placebo first) Intensive resistance, 20 hrs/wk and various other types No changes in body composition or strength for either placebo or HMB groups Lack of change in placebo group suggests overtraining Randomized, single-blind in collegiate football players, N = 264 3 g/day HMB or placebo for 10 days Preseason training camp No changes between baseline and post training in either placebo or HMB groups for anaerobic power No changes between placebo and HMB groups for changes in creatine kinase, myoglobin, testosterone, or cortisol levels Abbreviations: RM, repetition maximum. 1. Kreider RB, et al. Int J Sports Med. 1999;20(8): Slater G, et al. Int J Sport Nutr Exerc Metab. 2001;11(3): Ransone J, et al. J Strength Cond Res. 2003;17(1): Hoffman JR, et al. J Strength Cond Res. 2004;18(4):

Why the Discrepancy in HMB Studies?
There are potential differences in muscle metabolism between more highly trained and untrained athletes More potential for benefit probably in untrained athletes Length of HMB supplementation may have been insufficient in negative studies More highly trained athletes might require longer supplementation (only 1 negative study > 4 weeks duration) Very limited data (only 2 studies) on HMB doses over 3 g/day Larger body size might require a larger dose Type of training may be important Differences between laboratories There are several good meta-analyses and reviews of HMB and athletic performance1-6 Portal S, et al. J Ped Endocrinol Metab. 2010;23(7): Zanchi NE, et al. Amino Acids. 2011;40(4): Alon T, et al. Res Comm Mol Pathol Pharmacol. 2002;111(1-4): Nissen SL and Sharp RL. J Appl Physiol. 2003;94: Rowlands DS and Thomson JS. J Strength Cond Res. 2009;23(3): Wilson GJ, et al. Nutr Metab. 2008;5:1 DOI: /

Counterfeit HMB? The initial human research on HMB came from Steve Nissen’s laboratory at Iowa State The compound they studied and the one in their associated patents calcium -hydroxy--methylbutyrate A product marketed in the UK (HMB-1000, Maximuscle Ltd.) has been shown in one study to be ineffective at reducing exercise-induced muscle damage1 Subsequent analysis of the HMB-1000 product revealed that it actually contained no HMB2 It contains a related leucine metabolite (calcium hydroxy-methylbutyrate) This raises the potential issue that some “no effect” studies with HMB could be due to use of a product that does not contain HMB, but rather similar compounds that might not have the same biological activity 1Nunan et al. J Strength Cond Res 2010;24: 2Abumrad NN, Rathmacher JA. J Strength Cond Res 2011:25(7):1-2.

HMB and aerobic performance

HMB and Measures of Aerobic Capacity
Most of the research regarding HMB has focused on strength and body composition Ability to train harder with less muscle breakdown from exercise may be a mechanism through which HMB could facilitate aerobic performance 2 studies have evaluated aerobic capacity during HMB supplementation1,2 In these studies, the mechanism of how HMB might work is not clear Vukovich MD and Dreifort GD. J Strength Cond Res. 2001;15(4): Lamboley CR, et al. Int J Sport Nutr Exerc Metab. 2007;17(1):56-69.

Measures of Aerobic Capacity: Study 1
Randomized, double-blind, crossover study involving 8 endurance-trained cyclists Received 3 g/day HMB, leucine, or placebo for three 2-week supplementation periods, with 2-week washout periods in between Participants performed graded cycle ergometry tests VO2peak, VO2max , and lactate accumulation peak were similar between all groups Onset of blood lactate accumulation (VO2 at blood lactate level of 2 mM) was increased in both the HMB and leucine groups compared with the placebo group (9.1%, 2.1%, and 0.8%, respectively) Leucine had no other notable effects on aerobic parameters Lactate threshold (% VO2max) , and time to reach VO2peak were also increased in the HMB group compared with the leucine and placebo groups Blood HMB levels were much lower (40- to 60-fold) in the leucine group versus the HMB group Supports previous data on low conversion rates of leucine to HMB Vukovich MD and Dreifort GD. J Strength Cond Res. 2001;15(4):

Measures of Aerobic Capacity: Study 2
Randomized study involving 16 college students Received 3 g/day HMB or placebo for 5 weeks Students performed interval training 3 times/week on a treadmill Compared with the placebo group at 5 weeks, the HMB group had Increased VO2max (13.4% vs 8.4% for placebo; P < .05) Increased respiratory compensation point Decreased time to exhaustion at maximal oxygen consumption (Tmax) This was largely a function of the greater increase in VO2max The larger the VO2max, the tougher it is to run at that intensity Lamboley CR, et al. Int J Sport Nutr Exerc Metab. 2007;17(1):56-69.

HMB studies with creatine or with amino acids

HMB in Combination With Creatine
A natural question is whether synergistic or additive effects will occur during simultaneous supplementation with creatine and HMB Clinical data have reported mixed results Randomized, double-blind study involving 40 volunteers Received 3 g/day HMB, 20 g/day for 7 days followed by 10 g/day for 14 days creatine (Cr), creatine plus HMB (CrHMB), or placebo for 3 weeks Volunteers performed progressive resistance training Lean body mass gains (assessed via bioelectric impedance) were 0.92 kg, 0.39 kg, and 1.54 kg greater for Cr, HMB, and CrHMB groups, respectively compared with placebo Significant main effect for Cr group (P = .05), and a trend for HMB group (P = .08) Data were additive, no Cr × HMB interaction (P = .73) Similar results were reported for strength gains, with additive effects for Cr and HMB Reduction in exercise-induced creatine phosphokinase levels was greatest in the HMB group (main effect, P = .01) Addition of creatine antagonized the HMB effect (P = .04 for Cr × HMB interaction) Jówko E, et al. Nutrition. 2001;17(7-8):

HMB in Combination With Creatine
Randomized study in basketball players1 Received creatine, HMB, creatine and HMB, or placebo for 30 days Doses were not specified Players in the combination group had increased maximum power and total work output compared with the other groups No additional increase in lactate or fall in muscle pH 2 studies did not show benefits of the creatine/HMB combination2,3 Both studies were in 57 elite rugby players (N = 30; N = 27) Received 3 g/day HMB, 3 g/day creatine, creatine and HMB, or placebo for 6 weeks No benefits were observed on Muscular strength and endurance Leg power Anthropometry Aerobic ability Anaerobic ability Zajac A, et al. J Hum Kinet. 2003;10: O’Connor DM and Crowe MJ. J Strength Cond Res. 2007;21(2): O’Connor DM and Crowe MJ. J Sports Med Phys Fitness. 2003;43(1):64-68.

HMB in Combination With the Amino Acids Arginine, Glutamine, and Taurine
Randomized, double-blind study involving 17 healthy men who were recreationally active (no resistance training in previous 6 months) Received HMB plus amino acids (MA) or an isonitrogenous control twice daily for 12 weeks MA formula = 1.5 g HMB, 7 g glutamine, 7 g arginine, 3 g taurine, 5.8 g dextrose Control = 10 g glycine, 11.5 g alanine, 1.5 g glutamate, 1.5 g serine Volunteers performed resistance training 3 times/week (10 exercises for whole body) One light (12- to 14-repetition maximum [RM]), 1 moderate (8- to 10-RM), and 1 heavy (3- to 5-RM) day each week Outcome variables Strength (1-RM) Vertical jump power Hormonal and muscle damage responses to an acute bout of resistance training Body composition and circumferences Tendon size Results follow on next slides Kraemer WJ, et al. Med Sci Sports Exerc. 2009;41(5):

Body Composition Changes During Supplementation With HMB and Amino Acids
Body mass and lean body mass continuously increased in both groups Body fat continuously decreased in both groups After 12 weeks of training, the supplementation group had significantly improved body composition A B C CON MA CON MA CON MA 95 80 a,b 32 a,b 75 90 30 a 28 70 a a 85 26 Body mass, kg Lean body mass, kg 65 Body fat, % a,b 24 80 22 60 20 75 55 18 16 70 50 V1 V5 V8 V1 V5 V8 V1 V5 V8 Time point Time point Time point aSignificant difference from V1, P  .05 bSignificant difference from control, P  .05 Abbreviations: V1, before training; V5, after 6 wks; V8, after 12 wks. Kraemer WJ, et al. Med Sci Sports Exerc. 2009;41(5):

Strength and Power Changes During Supplementation With HMB and Amino Acids
Both muscle strength and power continuously increased in both groups After 6 weeks of training, the supplementation group had significantly improved muscle strength that remained enhanced at the 12-week assessment At 12 weeks, the supplementation group had significantly improved muscle power A B C CON MA CON MA CON MA a,b a,b 6000 120 a,b a 140 a,b a,b a 5500 100 5000 a a 120 Squat, kg Bench, kg Vertical jump power, w 4500 80 4000 100 3500 60 80 3000 V1 V5 V8 V1 V5 V8 V1 V5 V8 Time point Time point Time point aSignificant difference from V1, P  .05 bSignificant difference from control, P  .05 Abbreviations: V1, before training; V5, after 6 wks; V8, after 12 wks. Kraemer WJ, et al. Med Sci Sports Exerc. 2009;41(5):

Changes in Hormone Levels and Indicators of Muscle Damage During Supplementation With HMB and Amino Acids Compared with the placebo group, the supplementation group had Increased resting and exercise-induced testosterone levels Increase resting growth hormone concentrations Reduced pre-exercise cortisol concentrations Attenuated circulating creatine kinase and malondialdehyde concentrations Indicative of less muscle damage In general, the effects from supplementation on creatine kinase, malondialdehyde, and cortisol were more pronounced at the 12-week point in the study No dietary intake data were reported for the study Kraemer WJ, et al. Med Sci Sports Exerc. 2009;41(5):

HMB in the elderly and therapeutic/medical applications

HMB in the Elderly There are a number of nutritional problems in the elderly population for which there may be applications for HMB Sarcopenia due to aging and inactivity1 Bedrest Inability to perform exercise that can help maintain muscle mass Wound healing (eg, decubiti)2 Presence of disease states (eg, cancer, congestive heart failure) associated with significant cachexia3,4 Generalized malnutrition5 HMB has been studied in both healthy elderly and those with various conditions associated with loss of muscle mass and wound healing capacity Baier S, et al. JPEN J Parenter Enteral Nutr 2009;33(1):71-82. Williams JZ, et al. Ann Surg. 2002;236(3): Hsieh LC, et al. Asia Pac J Clin Nutr. 2006;15(4): May PE, et al. Am J Surg. 2002;183(4): Hsieh LC, et al. Asia Pac J Clin Nutr. 2010;19(2):

Body Composition and Protein Metabolism in Healthy Older Adults During HMB Supplementation
3 studies have evaluated HMB in relatively healthy elderly adults (> 70 years) Randomized, double-blind study involving 31 adults (men, 15; women, 16) 70 years of age1 Received 3 g/day HMB or placebo for 8 weeks Participants underwent an exercise program 5 day/week 2 randomized, double-blind studies involving 127 elderly adults (N = 50, all women; N = 77, men 38 and women 39)2,3 Received 2 to 3 g HMB to 2.25 g lysine + 5 to 7.5 g arginine per day or isocaloric, isonitrogenous placebo Study durations were 12 weeks2 and 1 year3 No exercise component General findings from these studies Some improvements in body composition (lean mass,  fat mass) Increased protein turnover Improvement in selected measures of strength and functional tests Improvements did not always occur in either placebo or HMB group Indicates that the participants might not have been able to do the exercises adequately Benefits were stronger during the earlier period of the studies and tapered toward the study end Vukovich MD, et al. J Nutr. 2001;131: Flakoll P, et al. Nutrition. 2004;20(5): Baier S, et al. JPEN J Parenter Enteral Nutr. 2009;33(1):71-82.

HMB and Wound Healing Effects of HMB on body composition and protein turnover led to investigations of HMB effects on collagen synthesis and wound healing Randomized study involving 35 healthy adults (men, 8; women, 27; mean age, 75 years) Creation of small wounds with plastic tubular inserts that were placed in the deltoid Received 14 g arginine + 3 g HMB + 14 g glutamine per day (n = 18) or an isocaloric, isonitrogenous control (n = 17) for 2 weeks At 2 weeks posttreatment Hydroxyproline concentration (surrogate for collagen production) was increased in the HMB group compared with the control group (72.2 nmol/cm implant vs 43.2 nmol/cm implant; P < .03) Total protein accumulation was similar between groups Total α-amino nitrogen (surrogate for total wound protein synthesis) was also similar between groups However, baseline characteristics of the 2 groups were not presented Comparable baseline wound healing is not established Williams JZ, et al. Ann Surg. 2002;236(3):

HMB and Cachetic-Prone Populations: HIV-Infected Patients
Randomized, double-blind study involving 43 patients infected with HIV who had unintentional weight loss > 5% over the previous 3 months Received 3 g HMB + 14 g glutamine + 14 g arginine per day or placebo (maltodextrin, isocaloric) for 8 weeks Would have been better to also have isonitrogenous placebo Outcome variables Body composition by air displacement plethysmography and skinfolds T-cell subsets Change in viral load Results follow on next slide Clark RH, et al. JPEN J Parenter Enteral Nutr. 2000;24(3):

Cumulative weight gain, kg Cumulative lean gain, kg
Outcomes During Supplementation With HMB and Amino Acids in HIV-Infected Patients Body composition improved in the supplementation group compared with the placebo group Differences were significant within 8 weeks T-cell subsets (CD3 and CD5) were also increased significantly in the supplementation group compared with the placebo group Viral load decreased significantly with HMB/Arg/Glut supplementation compared with placebo 5 Placebo HMB/Arg/Gln 3 b Placebo HMB/Arg/Gln 4 2 3 a Cumulative weight gain, kg 2 1 Cumulative lean gain, kg 1 -1 -1 Start 4 weeks 8 weeks Start 4 weeks 8 weeks aP = .009 bP = .003 Reprinted with permission from Clark RH, et al. JPEN J Parenter Enteral Nutr. 2000;24(3):

Other Positive HMB Studies in Cachectic-Prone Populations
Studies with 3 g HMB + 14 g glutamine 14 g arginine per day Randomized, double-blind study involving 32 patients with solid tumors who had unintentional weight loss > 5%1 Received HMB/arginine/glutamine, or isonitrogenous, isocaloric placebo for 24 weeks By 4 weeks, gains in body weight and fat-free mass were observed in the supplementation group compared with the placebo group At 23 weeks, positive effects from the supplementation were maintained Randomized, blinded study involving 100 critically ill trauma patients2 Received HMG, HMB/arginine/glutamine, or isonitrogenous, isocaloric placebo for 28 days After 7 days of supplementation Nitrogen retention was significantly improved in the supplemented groups compared with the placebo group (P = .05) Urinary 3-methylhistidine (indicator of muscle proteolysis) was unaffected by supplementation May PE, et al. Am J Surg. 2002;183(4): Kuhls DA, et al. J Trauma. 2007;62(1):

Other Positive HMB Studies in Cachectic-Prone Populations
Studies with HMB alone1,2 In 34 patients with chronic obstructive pulmonary disease who were randomized to 3 g/day HMB or control for 7 days, HMB-treated patients had improved indicators for inflammation and protein balance compared with the control group In 79 bed-ridden elderly adults who were randomized to 2 g/day HMB or control for 14 days, HMB-treated adults had reduced muscle protein breakdown compared with the control group Hsieh LC, et al. Asia Pac J Clin Nutr. 2006;15(4): Hsieh LC, et al. Asia Pac J Clin Nutr. 2010;19(2):

Studies Showing No Effects of HMB/Arginine/Glutamine Supplementation
Randomized study involving 40 patients with rheumatoid cachexia1 Received HMB/arginine/glutamine or isocaloric, isonitrogenous placebo for 12 weeks Similar improvements in body composition and physical function were reported in both groups Patients receiving supplementation were less cachectic vs other studies However, the May PE, et al. study had high dropout rate due to very sick population Randomized study involving 30 patients undergoing laparoscopic gastric bypass surgery2 Received 24 g HMB/arginine/glutamine twice daily or no supplementation post-operatively for 8 weeks No differences between groups in changes of body weight, composition, or resting metabolic rate No adverse effects on weight loss Marcora S, et al. Clin Nutr. 2005;24(3): Clements RH, et al. Surg Endosc. 2010;25(5):

HMB: Safety

Safety Profile of HMB: Animal Studies
Various animal studies (laboratory and livestock animals) have shown no adverse effects even at high doses (up to 4 g/kg)1 and some positive effects Decreased mortality (probably due to enhanced immunity)2,3 Decreased muscle protein breakdown4 Improved carcass quality (more lean, less fat)5 A 90-day toxicology study in rats with HMB at 5% of diet (3.49 g/kg for males, 4.16 g/kg for females) showed that this dose had no observed adverse effects6 This included changes in food consumption and body weight, as well as clinical chemistries, organ weights, hematology, and macro- and microscopic tissue examinations Papet I, et al. Br J Nutr. 1997;77(6): Nissen S, et al. Poult Sci. 1994;73(1): Peterson AL, et al. Immunopharm Immunotox. 1999;21(2): Holecek M, et al. Food Chem Toxicol. 2009;47(1): Van Koevering MT, et al. J Anim Sci. 1994;72(8): Baxter JH, et al. Food Chem Toxicol. 2005;43(12):

Safety Profile of HMB: Human Studies
HMB has been marketed extensively as a dietary supplement since 1996 with no pattern of adverse event reports Clinical studies evaluating HMB or HMB + creatine supplementation for periods of 3 to 8 weeks with doses up to 6 g/day HMB have shown1-3 No adverse hematological, hepatic, or renal effects Some tendency to decrease total and low-density lipoprotein cholesterol (–5.8 and –7.3%, respectively) and reduce systolic blood pressure (–4.4 mm Hg)2 Although HMB can be used for cholesterol synthesis, it appears that the cholesterol synthesis is localized (eg, muscle) and does not adversely affect blood cholesterol levels Clinical studies evaluating the combination of HMB/Arginine/Glutamine in healthy volunteers and patients with HIV or cancer showed4 Combination was safe Improvement in certain hematological parameters Gallagher PM, et al. Med Sci Sports Exerc. 2000;32(12): Nissen S, et al. J Nutr. 2000;130(8): Crowe MJ, et al. Int J Sport Nutr Exerc Metab. 2003;13(2): Rathmacher JA, et al. JPEN J Parenter Enteral Nutr. 2004;28(2):65-75.

Additional Information Regarding the Safety of HMB
No published study has reported any adverse effects of HMB However, some of these studies did not report adverse event data as part of the data presented There are very limited data in humans on HMB doses up to 6 g/day No treatment-related adverse events were reported Most HMB studies in humans have been ≤ 8 weeks There are some data out to 24 weeks showing safety Data on elderly are limited, but studies reviewed in this presentation in both healthy and clinical populations have not reported adverse events

HMB Summary HMB has been reported to be safe and well tolerated
Primary source of natural HMB is catabolism of the amino acid leucine HMB stimulates muscle protein synthesis and may also Increase cell membrane integrity via cholesterol synthesis Decrease indicators of muscle damage (creatine kinase levels) Be an anticatabolic agent Clinical results evaluating the benefits of HMB supplementation alone or with other supplementation on body composition and strength have been mixed Benefits may be reported once an optimal HMB dose and duration that correlates with an athletes size and training level is established Clinical results suggest that HMB improves Aerobic performance Conditions associated with loss of muscle mass Wound healing capacity HMB has been reported to be safe and well tolerated Data is limited and from short-duration studies

β-Hydroxy-β-Methylbutyrate (HMB)

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β-Hydroxy-β-Methylbutyrate (HMB)

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