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h2s
11-12-2012, 10:37 AM
Acute and timing effects of beta-hydroxy-beta-methylbutyrate (HMB) on indirect markers of skeletal muscle damage.


Acute and timing effects of beta-hydroxy-beta-methylbutyrate (HMB) on indirect markers of skeletal muscle damage.
Wilson JM, Kim JS, Lee SR, Rathmacher JA, Dalmau B, Kingsley JD, Koch H, Manninen AH, Saadat R, Panton LB.
Source

Department of Nutrition, Food & Exercise Sciences, Florida State University, Tallahassee, FL, USA.
Abstract
BACKGROUND:

While chronic β-Hydroxy β-Methylbutyrate (HMB) supplementation (≥ 2 wk) lowers exercise induced muscle damage, its acute or timing effects have not been examined. The purpose of this study was to investigate the acute and timing effects of oral HMB supplementation on serum creatine kinase (CK), lactate dehydrogenase (LDH), muscle soreness, and maximal voluntary contraction (MVC).
METHODS:

Sixteen non-resistance trained men (22 ▒ 2 yrs) were assigned to HMB-Pre or HMB-Post groups. In a crossover design, all subjects performed 55 maximal eccentric knee extension/flexion contractions on 2 occasions on either the right or left leg. HMB-Pre (N = 8) randomly received 3 grams of either a placebo or HMB before and a placebo after exercise. HMB-Post (N = 8) received a placebo before and either 3 grams of HMB or a placebo after exercise. Muscle damage tests were recorded before, at 8, 24, 48, and 72 hrs post exercise.
RESULTS:

There was a reduction in MVC and an increase in soreness in the quadriceps and hamstrings following exercise (p < 0.001). Although HMB-Pre approached significance in attenuating soreness for the quadriceps (p = 0.07), there was no time x group effect. Serum indices of damage increased, peaking at 48 hrs for CK (773%) (p < 0.001) and 72 hrs for LDH (180%) (p < 0.001). While there were no time x group effects of HMB on CK and LDH, post hoc analysis revealed that only HMB-Pre showed no significant increase in LDH levels following exercise.
CONCLUSION:

Our findings suggest no clear acute or timing effects of HMB supplementation. However, consuming HMB before exercise appeared to prevent increases in LDH.

h2s
11-12-2012, 10:40 AM
β-Hydroxy-β-methylbutyrate (HMβ) supplementation stimulates skeletal muscle hypertrophy in rats via the mTOR pathway


β-Hydroxy-β-methylbutyrate (HMβ) supplementation is used to treat cancer, sepsis and exercise-induced muscle damage. However, its effects on animal and human health and the consequences of this treatment in other tissues (e.g., fat and liver) have not been examined. The purpose of this study was to evaluate the effects of HMβ supplementation on skeletal muscle hypertrophy and the expression of proteins involved in insulin signalling. Rats were treated with HMβ (320 mg/kg body weight) or saline for one month. The skeletal muscle hypertrophy and insulin signalling were evaluated by western blotting, and hormonal concentrations were evaluated using ELISAs. HMβ supplementation induced muscle hypertrophy in the extensor digitorum longus (EDL) and soleus muscles and increased serum insulin levels, the expression of the mammalian target of rapamycin (mTOR) and phosphorylation of p70S6K in the EDL muscle. Expression of the insulin receptor was increased only in liver. Thus, our results suggest that HMβ supplementation can be used to increase muscle mass without adverse health effects.

╬▓-Hydroxy-╬▓-methylbutyrate (HM╬▓) supplementation stimulates skeletal muscle hypertrophy in rats via the mTOR pathway (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3048483/)

h2s
11-12-2012, 10:47 AM
Creatine and beta-hydroxy-beta-methylbutyrate (HMB) additively increase lean body mass and muscle strength during a weight-training program.


Creatine and beta-hydroxy-beta-methylbutyrate (HMB) additively increase lean body mass and muscle strength during a weight-training program.
Jˇwko E, Ostaszewski P, Jank M, Sacharuk J, Zieniewicz A, Wilczak J, Nissen S.
Source

Institute of Sport and Physical Education, Biala Podlaska, Academy of Physical Education, Warsaw, Poland.
Abstract

We investigated whether creatine (CR) and beta-hydroxy-beta-methylbutyrate (HMB) act by similar or different mechanisms to increase lean body mass (LBM) and strength in humans undergoing progressive resistance-exercise training. In this double-blind, 3-wk study, subjects (n = 40) were randomized to placebo (PL; n = 10), CR (20.0 g of CR/d for 7 d followed by 10.0 g of CR/d for 14 d; n = 11), HMB (3.0 g of HMB/d; n = 9), or CR-and-HMB (CR/HMB; n = 10) treatment groups. Over 3 wk, all subjects gained LBM, which was assessed by bioelectrical impedance analysis. The CR, HMB and CR/HMB groups gained 0.92, 0.39, and 1.54 kg of LBM, respectively, over the placebo group, with a significant effect with CR supplementation (main effect P = 0.05) and a trend with HMB supplementation (main effect P = 0.08). These effects were additive because there was no interaction between CR and HMB (CR x HMB main effect P = 0.73). Across all exercises, HMB, CR, and CR/HMB supplementation caused accumulative strength increases of 37.5, 39.1, and 51.9 kg, respectively, above the placebo group. The exercise-induced rise in serum creatine phosphokinase was markedly suppressed with HMB supplementation (main effect P = 0.01). However, CR supplementation antagonized the HMB effects on serum creatine phosphokinase (CR x HMB interactive effect P = 0.04). Urine urea nitrogen and plasma urea were not affected by CR supplementation, but both decreased with HMB supplementation (HMB effect P < 0.05), suggesting a nitrogen-sparing effect. In summary, CR and HMB can increase LBM and strength, and the effects are additive. Although not definitive, these results suggest that CR and HMB act by different mechanisms.

Creatine and beta-hydroxy-beta-methylbutyr... [Nutrition. 2001 Jul-Aug] - PubMed - NCBI (http://www.ncbi.nlm.nih.gov/pubmed/11448573)

h2s
11-12-2012, 10:55 AM
Effects of beta-hydroxy-beta-methylbutyrate on muscle damage after a prolonged run.


Effects of beta-hydroxy-beta-methylbutyrate on muscle damage after a prolonged run.
Knitter AE, Panton L, Rathmacher JA, Petersen A, Sharp R.
Source

Human Performance Laboratory, Iowa State University, Ames, Iowa 50011, USA.
Abstract

This study examined the effects of supplemental beta-hydroxy-beta-methylbutyrate (HMB) on muscle damage as a result of intense endurance exercise. Subjects (n = 13) were paired according to their 2-mile run times and past running experience. Each pair was randomly assigned a treatment of either HMB (3 g/day) or a placebo. After 6 wk of daily training and supplementation, all subjects participated in a prolonged run (20-km course). Creatine phosphokinase and lactate dehydrogenase (LDH) activities were measured before and after a prolonged run to assess muscle damage. The placebo-supplemented group exhibited a significantly greater (treatment main effect, P = 0.05) increase in creatine phosphokinase activity after a prolonged run than did the HMB-supplemented group. In addition, LDH activity was significantly lower (treatment main effect, P = 0.003) with HMB supplementation compared with the placebo-supplemented group. In conclusion, supplementation with 3.0 g of HMB results in a decreased creatine phosphokinase and LDH response after a prolonged run. These findings support the hypothesis that HMB supplementation helps prevent exercise-induced muscle damage.

Effects of beta-hydroxy-beta-methylbutyrate o... [J Appl Physiol. 2000] - PubMed - NCBI (http://www.ncbi.nlm.nih.gov/pubmed/11007567)

h2s
11-12-2012, 11:20 AM
Vitamin D status affects strength gains in older adults supplemented with a combination of β-hydroxy-β-methylbutyrate, arginine, and lysine: a cohort study.


Vitamin D status affects strength gains in older adults supplemented with a combination of β-hydroxy-β-methylbutyrate, arginine, and lysine: a cohort study.
Fuller JC Jr, Baier S, Flakoll P, Nissen SL, Abumrad NN, Rathmacher JA.
Source

Metabolic Technologies, Inc, Iowa State University Research Park, Ames, USA.
Abstract
BACKGROUND:

Older adults supplemented for 1 year with β-hydroxy-β-methylbutyrate, arginine, and lysine (HMB/ARG/LYS) were previously shown to have significant gains in fat-free mass (FFM) but not muscular strength.
OBJECTIVE:

Recently, increasing levels of serum vitamin D have been associated with an increase in muscle function, particularly in the elderly. To determine if vitamin D status may have limited strength gain in participants supplemented with HMB/ARG/LYS, the authors performed post hoc analysis of strength based on the participants' vitamin D status.
METHODS:

Elderly (age 76.0 ▒ 1.6 years) adults were recruited for a double-blinded, controlled study and were randomly assigned to either an isonitrogenous control (n = 37) or HMB/ARG/LYS (n = 40) for the yearlong study. Participants were further segregated based on their vitamin D status of either <30 or ≥30 ng 25OH-vitD(3)/mL serum, and an analysis was performed on the 4 cohorts.
RESULTS:

Regardless of vitamin D status, HMB/ARG/LYS resulted in significantly increased FFM (P < .02), but only in those with vitamin D status ≥30 ng 25OH-vitD(3)/mL was there a significant increase in strength with HMB/ARG/LYS (P < .01). Control-supplemented participants, regardless of vitamin D status, and the HMB/ARG/LYS-supplemented participants with vitamin D status <30 ng 25OH-vitD(3) failed to show improvements in strength.
CONCLUSIONS:

The nutrient cocktail of HMB/ARG/LYS alone was effective in increasing muscle mass regardless of vitamin D status, but accompanying strength increases were observed only when participants also had adequate vitamin D status indicating a synergistic effect between the HMB/ARG/LYS and vitamin D.

Vitamin D status affects streng... [JPEN J Parenter Enteral Nutr. 2011] - PubMed - NCBI (http://www.ncbi.nlm.nih.gov/pubmed/21807930)