Shockrock3
New Member
I have been reading in the muscle magazines about a supplement called HMB.
What is it and can it be of any help?
Beta-hydroxy-beta-methylbutyrate (HMB) has emerged as a very hot supplement in the strength training population. HMB is a metabolite (by product) of leucine metabolism. Leucine and a-ketoisocapronate (KIC) are proposed to decrease nitrogen and protein loss by inhibiting protein breakdown and thus are called anticatabolic or antiproteolytic. However, this action in animals and humans has only been shown to occur in situations of severe stress or trauma in which protein breakdown is greatly elevated.
HMB is produced from KIC by the enzyme KIC-dioxygenase and, at least in the pig, is produced solely from leucine. Some researchers feel that HMB is responsible fro the inhibitory effect on protein breakdown.
With regard to the second part of the question, "Can it be of any help?", there was a recent research paper which attempted to answer this question (Effect of leucine metabolite b-hydroxy-b-methylbutyrate on muscle metabolism during resistance exercise training. Journal of Applied Physiology Vol.81(5): 2095-2104, 1996). The purpose of this study was to determine whether giving HMB to subjects engaging in strength training exercise would slow protein breakdown. This study also examined the effects of one group ingesting 175 grams/day of protein versus a group ingesting 117 grams/day. And finally, the investigators conducted a second longer study to determine whether the changes in body composition and strength seen during the first study were evident over a longer period of time.
In study one, 41 male volunteers, 19-29 years of age, were selected, and 32 male volunteers, 19-22 years of age, were selected for study two. The subjects averaged 82.7 + 1.6 kg (about 182 lbs.). The treatment groups were control (n=6) control plus 1.5 g HMB/day (n=6), control plus 3 g HMB/day (n=8), high protein (n=7), high protein plus 1.5 g HMB/day (n=7), and high protein plus 3 g HMB/day (n=7).
The strength training program consisted of both free weights and machines. It worked each muscle group once or twice weekly. The exercises included bench press, lat pulldown, seated rows, pec deck, preacher curls, dumbbell curls, triceps pushdown, seated leg press, calf raises, leg curls, leg extension, sit-ups, inclined leg life, and back extensions. The subjects lifted three times per week with at least one day of rest between sessions. During this three week study, each subject lifted 10 times (5 upper body and 5 lower body). Each exercise included 2 sets of 10 reps at 30 and 60% of the individual's 1 RM as a warm-up, followed by 3 sets of 3-5 reps at 90% of 1 RM. When necessary, weights were adjusted to assure failure on the third to fifth rep.
After each workout, the average weight lifted on the last to sets was increased by 2% and these weights were used as the target weight to be lifted at the next session. Each session was monitored by trained supervisors who recorded weights and judged whether changes in weights were necessary to produce failure after three to five reps.
In this study, muscle strength was assessed by calculating the average weight lifted during the last three working sets of each exercise. The average weight was then multiplied by the number of repetitions the weight was lifted to yield a work index.
The results from the first study, relative to body composition changes, revealed the following: 1) Protein level had no significant effect on body weight change. 2) The loss of fat weight over the 3 week study ranged from 1-1.8 kg and there was not a significant difference among the groups. 3) Lean tissue increased 0.4 kg for the non- HMB group, 0.8 kg for the 1.5 g HMB group, and 1.2 kg for the 3 g HMB group.
The gains in muscle strength revealed that all subjects increased the amount of weight lifted in each exercise and the total number of abdominal efforts during the 3 week training period. No differences in the amount of weight lifted were seen between the normal and high protein groups for any of the exercises. The HMB supplementation did not make a significant difference in upper body strength but it did for lower body strength and total strength [when upper body and lower body were added together]. The nonsupplemented group increased total strength 8% during the 3 week program while the 1.5 g HMB and 3 g HMB group increased total strength 13% and 18.4%, respectively.
To access the inhibition of protein breakdown, the investigators analyzed plasma CK levels, 3-MH loss in the urine, and plasma amino acid levels. HMB supplemented subjects had lower levels of plasma CK, but because of variations among the subjects, it was not significant. HMB had a positive effect of 3-MH levels the first two weeks of the study but not the third week. Plasma concentrations of most amino acids were not significantly changed by either protein intake or HMB supplementation. However, the essential amino acids increased 32% in the nonsupplemented subjects and decreased 9 and 18% in the 1.5 g HMB and 3 g HMB groups, respectively.
In study 2, which lasted seven weeks, all subjects tended to increase body weight and fat weight, and there was no significant beneficial effect of HMB supplementation on these measures. The only difference was the HMB supplemented group tended to increase their fat free mass gains earlier in the study. However, on the last day of the study, fat free mass was not significantly different between the groups.
In the seven week study the nonHMB group increased their bench press from 315 to 321 while the HMB groups increased from 299 to 314, this difference was significant. The nonHMB group increased their squat from 221 to 250. The HMB group increased their squat from 388 to 420 and their hang cleans from 222 to 252. For both the squat and the hang clean, HMB did not have a significant impact.
The authors summarized that dietary supplementation of 3 g of HMB/day for subjects engaging in intense strength training exercise resulted in an increased gain of fat free mass and accompanying increase in strength. Muscle protein breakdown was also decreased with HMB.
I have a different view of how to summarize the information gained from both the three-week and seven-week studies. In terms of body composition changes, if one were to start strength training and supplemented with HMB they may gain more fat free mass in the first three weeks of a seven-week training program than if they did not supplement with HMB. However, total fat free mass gain would possibly be the same at the end of the seven week training program with or without HMB supplementation. The strength gains between the first three-week study and the second seven-week study for the HMB supplemented groups are in somewhat of a conflict. The three-week study did not find much of a difference in upper body strength byt lower body strength between nonsupplemented and HMB supplemented groups. The second seven-week study found just the opposite. I interpret this to mean that HMB may not have as significant effect on strength progression as the advertisements lead one to believe.
According to some literature I have received in the mail, HMB supplementation costs about $35 for a bottle of 120 capsules, of 250 mg HMB. This will last an individual 10 days! How can anyone look an honest, hard working, high school football player [or any hard working individual for that matter] in the face and tell them they need to shell out over $100 a month for a supplement that may not make that much of a difference after three to four weeks? They are better off using the money at a local grocery store. HMB may have more relevance in a hospital setting with trauma patients and if it has any application in sports it may be with bodybuilders undergoing extreme dieting in preparation for a contest. Until more studies are performed, I would not look at HMB as being a miracle maker.
Shock
What is it and can it be of any help?
Beta-hydroxy-beta-methylbutyrate (HMB) has emerged as a very hot supplement in the strength training population. HMB is a metabolite (by product) of leucine metabolism. Leucine and a-ketoisocapronate (KIC) are proposed to decrease nitrogen and protein loss by inhibiting protein breakdown and thus are called anticatabolic or antiproteolytic. However, this action in animals and humans has only been shown to occur in situations of severe stress or trauma in which protein breakdown is greatly elevated.
HMB is produced from KIC by the enzyme KIC-dioxygenase and, at least in the pig, is produced solely from leucine. Some researchers feel that HMB is responsible fro the inhibitory effect on protein breakdown.
With regard to the second part of the question, "Can it be of any help?", there was a recent research paper which attempted to answer this question (Effect of leucine metabolite b-hydroxy-b-methylbutyrate on muscle metabolism during resistance exercise training. Journal of Applied Physiology Vol.81(5): 2095-2104, 1996). The purpose of this study was to determine whether giving HMB to subjects engaging in strength training exercise would slow protein breakdown. This study also examined the effects of one group ingesting 175 grams/day of protein versus a group ingesting 117 grams/day. And finally, the investigators conducted a second longer study to determine whether the changes in body composition and strength seen during the first study were evident over a longer period of time.
In study one, 41 male volunteers, 19-29 years of age, were selected, and 32 male volunteers, 19-22 years of age, were selected for study two. The subjects averaged 82.7 + 1.6 kg (about 182 lbs.). The treatment groups were control (n=6) control plus 1.5 g HMB/day (n=6), control plus 3 g HMB/day (n=8), high protein (n=7), high protein plus 1.5 g HMB/day (n=7), and high protein plus 3 g HMB/day (n=7).
The strength training program consisted of both free weights and machines. It worked each muscle group once or twice weekly. The exercises included bench press, lat pulldown, seated rows, pec deck, preacher curls, dumbbell curls, triceps pushdown, seated leg press, calf raises, leg curls, leg extension, sit-ups, inclined leg life, and back extensions. The subjects lifted three times per week with at least one day of rest between sessions. During this three week study, each subject lifted 10 times (5 upper body and 5 lower body). Each exercise included 2 sets of 10 reps at 30 and 60% of the individual's 1 RM as a warm-up, followed by 3 sets of 3-5 reps at 90% of 1 RM. When necessary, weights were adjusted to assure failure on the third to fifth rep.
After each workout, the average weight lifted on the last to sets was increased by 2% and these weights were used as the target weight to be lifted at the next session. Each session was monitored by trained supervisors who recorded weights and judged whether changes in weights were necessary to produce failure after three to five reps.
In this study, muscle strength was assessed by calculating the average weight lifted during the last three working sets of each exercise. The average weight was then multiplied by the number of repetitions the weight was lifted to yield a work index.
The results from the first study, relative to body composition changes, revealed the following: 1) Protein level had no significant effect on body weight change. 2) The loss of fat weight over the 3 week study ranged from 1-1.8 kg and there was not a significant difference among the groups. 3) Lean tissue increased 0.4 kg for the non- HMB group, 0.8 kg for the 1.5 g HMB group, and 1.2 kg for the 3 g HMB group.
The gains in muscle strength revealed that all subjects increased the amount of weight lifted in each exercise and the total number of abdominal efforts during the 3 week training period. No differences in the amount of weight lifted were seen between the normal and high protein groups for any of the exercises. The HMB supplementation did not make a significant difference in upper body strength but it did for lower body strength and total strength [when upper body and lower body were added together]. The nonsupplemented group increased total strength 8% during the 3 week program while the 1.5 g HMB and 3 g HMB group increased total strength 13% and 18.4%, respectively.
To access the inhibition of protein breakdown, the investigators analyzed plasma CK levels, 3-MH loss in the urine, and plasma amino acid levels. HMB supplemented subjects had lower levels of plasma CK, but because of variations among the subjects, it was not significant. HMB had a positive effect of 3-MH levels the first two weeks of the study but not the third week. Plasma concentrations of most amino acids were not significantly changed by either protein intake or HMB supplementation. However, the essential amino acids increased 32% in the nonsupplemented subjects and decreased 9 and 18% in the 1.5 g HMB and 3 g HMB groups, respectively.
In study 2, which lasted seven weeks, all subjects tended to increase body weight and fat weight, and there was no significant beneficial effect of HMB supplementation on these measures. The only difference was the HMB supplemented group tended to increase their fat free mass gains earlier in the study. However, on the last day of the study, fat free mass was not significantly different between the groups.
In the seven week study the nonHMB group increased their bench press from 315 to 321 while the HMB groups increased from 299 to 314, this difference was significant. The nonHMB group increased their squat from 221 to 250. The HMB group increased their squat from 388 to 420 and their hang cleans from 222 to 252. For both the squat and the hang clean, HMB did not have a significant impact.
The authors summarized that dietary supplementation of 3 g of HMB/day for subjects engaging in intense strength training exercise resulted in an increased gain of fat free mass and accompanying increase in strength. Muscle protein breakdown was also decreased with HMB.
I have a different view of how to summarize the information gained from both the three-week and seven-week studies. In terms of body composition changes, if one were to start strength training and supplemented with HMB they may gain more fat free mass in the first three weeks of a seven-week training program than if they did not supplement with HMB. However, total fat free mass gain would possibly be the same at the end of the seven week training program with or without HMB supplementation. The strength gains between the first three-week study and the second seven-week study for the HMB supplemented groups are in somewhat of a conflict. The three-week study did not find much of a difference in upper body strength byt lower body strength between nonsupplemented and HMB supplemented groups. The second seven-week study found just the opposite. I interpret this to mean that HMB may not have as significant effect on strength progression as the advertisements lead one to believe.
According to some literature I have received in the mail, HMB supplementation costs about $35 for a bottle of 120 capsules, of 250 mg HMB. This will last an individual 10 days! How can anyone look an honest, hard working, high school football player [or any hard working individual for that matter] in the face and tell them they need to shell out over $100 a month for a supplement that may not make that much of a difference after three to four weeks? They are better off using the money at a local grocery store. HMB may have more relevance in a hospital setting with trauma patients and if it has any application in sports it may be with bodybuilders undergoing extreme dieting in preparation for a contest. Until more studies are performed, I would not look at HMB as being a miracle maker.
Shock
