HMB-supplementering för styrketräning och annan idrott, review

[King Grub]

Amino acids such as leucine and its metabolite alpha-ketoisocaproate (KIC), are returning to be the focus of studies, mainly because of their anti-catabolic properties, through inhibition of muscle proteolysis and enhancement of protein synthesis. It is clear that these effects may counteract catabolic conditions, as well as enhance skeletal muscle mass and strength in athletes. Moreover, beta-hydroxy-beta-methylbutyrate (HMB) has been shown to produce an important effect in reducing muscle damage induced by mechanical stimuli of skeletal muscle. This review aims to describe the general scientific evidence of KIC and HMB supplementation clinical relevance, as well as their effects (e.g., increases in skeletal muscle mass and/or strength), associated with resistance training or other sports. Moreover, the possible mechanisms of cell signaling regulation leading to increases and/or sparing (during catabolic conditions) of skeletal muscle mass are discussed in detail based on the recent literature.

Amino Acids. 2010 Jul 6. HMB supplementation: clinical and athletic performance-related effects and mechanisms of action.

Artikeln: https://springerlink.metapress.com/content/4j7255632652567v/resource-secured/?target=fulltext.html&sid=hdxdovu05howwa55ybpw3m45&sh=www.springerlink.com

[macsacre]

HMB
Most people involved with sports nutrition and sports nutrition supplements has
heard or read about Beta-hydroxy beta-methyl-butyrate or HMB for short. HMB
appears to be one of those classic supplements that looks great in the lab but has
had a rocky track record with “real world” users. Let me back up a moment.
HMB is actually a metabolite of the amino acid L-leucine. L-leucine is one of three
amino acids known as the branched chain amino acids or BCAA (isoleucine and
valine being the other two).
It has been known for a long time that BCAA play a critical role in the turn over of
lean body tissues (muscle) and is muscle sparing (i.e. anti-catabolic) in a variety of
muscle wasting states. Of the three BCAA, L-leucine appears to be the most
important to preserving hard earned muscle mass and intense exercise and certain
disease states have been shown to eat up a great deal of L-leucine. So far so good!
The main drawback of L-leucine is the fact that you must use large amounts of this
amino acid to get a positive effect making it both expensive and impractical. Many
studies that showed benefits were in fact done intravenously and used as much as 5
grams per hour of L-leucine!
That my friend is a lot of leucine.
So, it was theorized there might be a metabolite of this ultra important amino acid
that was responsible for many of the positive effects of L-leucine but could be
taken in far lower doses and by mouth (as opposed to having a tube stuck in your
arm). That metabolite appears to be HMB.
Animal research with HMB has been impressive. During stressful conditions,
animals will often lose weight and/or become quite ill. Some even die. This of
course can be quite expensive for any company trying to make a living from these
animals in one way or another. When animals were fed HMB they found a large
reduction in mortality rates, increases in muscle mass, and improvements in
immune function in the animals fed HMB.
Several studies in humans have also looked promising. Studies using both trained
and untrained subjects found increases in muscle and decreases in bodyfat in
people ingesting just three grams (3000mg) of HMB per day.
The average was approximately 2-4 pounds of muscle put on with an equal amount
of fat taken off over a four week period. The scientists also found that HMB
positively affected several biochemical markers of intense exercise that would lead
one to believe that there was a reduction of muscle wasting in people taking HMB.
“So what’s the problem,” you ask? The problem has been mainly that what looked
so promising in the research has not been fully realized in the real world, hence my
introduction to this section.
Several follow up studies with HMB in people also failed to find any results. Feed
back from real world users has been generally negative with HMB. Some seem to
feel they have benefited from it while most found HMB a big waste of money.
Were the studies that found benefits flawed? Are some people not taking enough?
Does it depend on the nutritional status of the person using it and/or how they
train?
It’s not known for sure at this time, but considering the costs of HMB and the fact
there are other less expensive alternatives that clearly work (i.e., creatine) I see no
reason for hard working athletes to spend money on HMB until a definitive answer
can be found. At this time, HMB gets a thumb's down for building muscle, but if
you want to give it a try, I will not hold it against you

Mortimore, G.E., and A. R. Poso, et al. “Multiphasic Control of Hepatic Protein
Degradation by regulatory Amino Acids, General Features and Hormonal
Modulation,” Journal of Biological Chemistry 262 (1987), p 16322-16327.
Flakoll, P.J. and M. J. VandeHaar, et al. “Influence of alpha-Ketoisocaproate on
lamb Growth,” Journal of Animal Science 69/4 (1991), p. 1461-1467.
Van Koevering, M. and Nissen, S. “Oxidation of Leucine and Alpha-
Ketoisocaporate to ß-hydroxy ß-methylbutyrate In Vivo (Abstract),” American
Journal of Physiology 261/1 (1992).
Nonnecke, B. J., Franklin, S. T. and Nissen, S. “Leucine and its Catabolites alter
mitogen-stimulated DNA synthesis by bovine lymphocytes,” Journal of Nutrition
121/10 (1991), p. 1665-1672.
Buckspan, R. B., and E. Hoxyworth. “Alpha-Ketoisocaproate is superior to
Leucine in sparing muscle glucose during progressive fasting in normal male
volunteers," American Journal of Physiology 251 (1983), p. E648-E653.
Nair, K.S., R. G. Schwarts and S. Wells. “Leucine as a regulator of whole body
and skeletal muscle protein metabolism in humans,” American Journal of
Physiology 263 (1992), p. E928-934.
Chua, B., D. L. Siehle and H. E. Morgan. “Effects of Leucine and Metabolites of
Branched Chain Amino Acids on protein turnover in heart,” Journal of Biological
Chemistry 254 (1979), p. 8358-8362.
May, M. E. and M. G. Buse. “Effects of branched chain amino acids on protein
turnover,” Diabetes Metab. Rev 5/3 (1989), p. 227-245.
Talleyrand, V. and A. Dorn, et al. “Effects of feeding ß-hydroxy ß-methylbutyrate
on immune function in stressed calves,” FASEB Journal 8 (1994), p. A951.
Nissen, S. and Morrical, D., et al. “The effects of the leucine catabolite ß-hydroxy
ß-methylbutyrate on the growth and health of growing lambs,” Journal of Animal
Science 77 (1994), p. 243.
Van Koevering, M.T., H. G. Dolezal and et al. “Effects of ß-hydroxy ßmethylbutyrate
on performance and carcass quality of feedlot steers,” Journal of
Animal Science 72 (1994), p. 1927-1935.
Nissen, S. and J. Panton, et al. “Effects of ß-hydroxy ß-methylbutyrate (HMB)
supplementation on strength and body composition of trained and untrained males
undergoing intense resistance training,” Experimental Biology Conference
Presentation Abstract (1996).

[King Grub]

Klistra inte in random texter utan källa.

[Ondskapelsen]

Klistra inte in random texter utan källa.

Jag skrattar ihjäl mig åt din nya avatar. Vad i helvete!

mer on topic:
Vad är poängen? vad har dom kommit fram till? det gamla vanliga?

[TSullivanM]

Okej men vi som inte har tillgång till artikeln, kan nån förklara vad dem kommer fram till?

[Ola Wallengren]

Ungefär det här:

Conclusions

1. Although a meta-analysis by Nissen and Sharp (2003)
has indicated that the effects of HMB on strength and
lean mass are statistically significant, this review has
received some criticism that must be taken into
account. The fact that it analyzed only nine studies
with HMB supplementation, which are conducted by
three distinct groups of researchers, may present a
significant bias to the conclusions proposed. Subsequent
studies should investigate the reason for the
heterogeneity observed in the literature.

2. Another crucial point to be considered is that the
proposed mechanisms of action of HMB involves
increased sarcolemmal integrity. The inconsistent
findings in athletes may be partly explained by the
lower degree of muscle damage caused by the exercise
stimulus in this population. Thus, considering this
aspect, training protocols that are sufficiently intense
and accrued should be established to test the effectiveness
of HMB on this variable.

3. The vast majority of studies have employed 3 g/day of
HMB, grounded in evidence that this dose produces
better results than 1.5 g/day and is equivalent to
6 g/day. Further studies are required to validate this
hypothesis by varying the dose given, the supplement
and the degree of catabolism and adopting different
training intensities.

4. The mechanisms of action of HMB must also be
explored. Although experiments in vitro and in animal
models provided a major breakthrough in this field,
human studies are lacking. Considering the great
spectrum of action of HMB in modifying the activity
and expression of various genes and proteins, deeper
use of molecular biology tools could provide new
insights into the mechanisms underlying the effects of
supplementation.

5. Finally, the therapeutic use of this supplement is quite
promising. Additional clinically controlled studies,
with important primary endpoints, must be conducted
in patients with AIDS, trauma, cancer, malnutrition,
and inflammation, among other frameworks of severe
catabolism. Likewise, studies should examine the
possibility that athletes could benefit from HMB in
periods of rehabilitation, during which the loss of lean
mass and strength are inevitable

[jontet]

lite offtopic men vet man någonting om risker/ev. biverkningar av supplementering med hmb?

[King Grub]

Det anses vara säkert vid ett intag av upp till 3 gram per dygn.

http://jn.nutrition.org/cgi/content/full/130/8/1937

Det finns inget som säger att större doser innebär en hälsorisk, men det är inte undersökt.

[hejhopp79]

HMB är underskattat.

Har själv kört på det i perioder och jäklar vad jag orkar köra hårdare utan att känna mig "sliten". En period kombinerade jag mycket konditionsträning med styrketräning och HMB:n gjorde att jag alltid kände mig fräsch fastän jag tränade i stort sett varje dag.

Skulle säga att HMB nästan är up there med kreatin, för mig i alla fall.

[cero]

Vad är hmb?

[Eddie Vedder]

Vad är hmb?

http://en.wikipedia.org/wiki/Beta-Hydroxy_beta-methylbutyric_acid

[sandery3]

Många verkar tala illa om smaken på HMB, men jag älskar verkligen det kosttillskottet. Fun light täcker den fullständigt *drool*

Det har verkligen varit en uppbackning under min senaste deff.

[jontet]

om hmb är en metabolit till leucin som är en eaa, vore det lite kaka på kaka att slänga i sig motsvarande 3g hmb fördelat på före/efter passet tillsammans med vassle?

Supplementering med vassle uppvisar väl liknande resultat som hmb gör här i samband med styrketräning(ökad lbm och styrka) och då kanske resultatet av vassle+hmb blir likadant som ett av supplementen var för sig?

[Tanner]

om hmb är en metabolit till leucin som är en eaa, vore det lite kaka på kaka att slänga i sig motsvarande 3g hmb fördelat på före/efter passet tillsammans med vassle?


Svårt att säga om det är kaka på kaka eller inte.

Det kan lika gärna vara så att du behöver få en kraftig ökning av HMB i blodet under en kort tid för att få en stimulering, och att nedbrytningen av leucin är för långsam för att få en tillräckligt snabb höjning HMB nivåerna.

[Sniggel]

Svårt att säga om det är kaka på kaka eller inte.

Det kan lika gärna vara så att du behöver få en kraftig ökning av HMB i blodet under en kort tid för att få en stimulering, och att nedbrytningen av leucin är för långsam för att få en tillräckligt snabb höjning HMB nivåerna.

Har för mig att den dos som man brukar rekommenderas vid HMB-supplementering motsvarar den mängd HMB som bildas vid intag av uppemot 100g leucin. Med det i åtanke tror jag inte det blir kaka på kaka av att ta HMB och ett proteinsyntesstimulerande eaa- eller proteintillskott samtidigt.

[ajsen]

Ska detta endast intas i samband med träning eller går när som helst på dygnet bra?

[EiseltUK]

Ska detta endast intas i samband med träning eller går när som helst på dygnet bra?

En dos före träningen är inte fel men annars är effekten av HMB något som byggs upp på längre sikt vilket bidrar att du t ex skulle kunna ta en dos morgon, en dos före träning och en på kvällen.