HMB's Use In Athletics
HMB, or "beta-hydroxy beta-methylbutyrate", is a metabolite of
the amino acid Leucine and is produced naturally by the human body. HMB
is produced from a metabolite of leucine, called ketoisocaproate (KIC),
by the enzyme KIC-dioxygenase.
You may have first heard of HMB during the summer Olympics of 1996
when American swimmers were quoted in newspaper articles as saying,
"they had benefited from using HMB during their training".
Steven Nissen and his colleagues have performed the only study to
date of HMB on humans. The researchers agree that the mechanism by
which HMB impacts muscle proteolysis and function is not currently
known. Nevertheless there are a number of postulations. "The high
substrate concentration required by the dioxygenase enzyme compared
with the liver concentration of KIC suggests that HMB production in the
body may be a first-order reaction controlled by enzyme and KIC
concentrations. It has been calculated that, under normal conditions,
about 5% of leucine oxidation proceeds via this pathway. Therefore, if
humans are assumed to have enzyme actions similar to those seen in
pigs, a 70-kg human would produce from .2 to .4 g HMB/day depending on
the level of dietary leucine. At leucine intakes of 20-50 g/day (which
are used therapeutically), the concentrations of leucine and KIC in the
liver increase and could result in HMB production reaching gram
quantities per day". Some studies involving HMB supplementation to the
diet of steers and pigs have been shown to improve caracass quality.
Based on these findings, it has been hypothesized that supplementing
the diet with HMB may inhibit protein degradation during periods of
increased proteolysis such as resistance training.
Companies who promote the product claim that humans neither produce
enough HMB in their bodies, nor do they eat such HMB-containing foods
(e.g. catfish and grapefruit) regularly enough to provide the full
benefits of HMB. Researchers claim that when we input extra amounts of
HMB into our bodies the metabolite acts as a performance enhancer for
such activities as weight lifting and sprinting. In effect, companies
claim that HMB boosts strength levels, enhances gains in muscle size
and strength, and prevents post-workout muscle tissue breakdown. The
marketing companies do not make exactly clear how the product works,
but they have formulated a few widely accepted ideas which are seen on
the advertisement postings in many nutritional stores. Many of them
believe that excess amounts of HMB in the body cause an interference
with the body?s natural process of protein breakdown (particularly
after a workout).
Due to the fact that a limited number of HMB studies have been
performed on humans, we must also consider the results of the tests on
animals. Perhaps there is a connection between the noted improvements
in the two animal tests and those of humans. This data alone, however,
is insufficient. Since HMB is a relatively new product, one must take
into consideration the possible side effects or other negative aspects
of upsetting a natural balance within the body.
The patent for HMB use as a sport supplement is owned by Iowa State
University Research Foundation (ISURF) and has been licensed to
Metabolic Technologies, Inc. under U.S. patent number 5,348,979. If you
come across an HMB supplement that doesn't have this patent number on
its label, don't buy it. It's very likely fake. This does not mean that
an HMB product that doesn't have the patent number on the label is
certainly counterfeit. The current patents protect the nutritional uses
of HMB for promoting nitrogen retention and the explanation of those
methods. These "use" patents do not prevent others from manufacturing
HMB, it just prevents them from saying their products improve nitrogen
retention and muscle growth. However, because HMB is not a simple
nutrient to manufacture, in all likelihood any product that doesn't
have the patent #5,348,979 is fraudulent.
In terms of safety, a number of animal species have been fed large
amounts of HMB for varying periods of time. In all the animal studies,
there were no adverse effects or increases in death rates. When animals
were autopsied, there were no pathological changes in their organs or
tissues. Instead, the investigators found a lowered LDL (bad
cholesterol) response, increased immune function, fewer respiratory
illnesses, more lean body mass, and reduced fat mass. Even when pigs
were fed 100 times that used by humans, no problems occurred.
In human studies using 2-5 grams of HMB, blood chemistry, liver
function, and kidney function all remained normal. All the human
studies that looked at cholesterol found an average LDL decrease of 7%.
Nutritional strategies of overfeeding, ingesting
carbohydrate/protein before and after exercise, and dietary
supplementation of various nutrients [e.g. protein, glutamine,
branched-chain amino acid, creatine, leucine, beta-hydroxy
beta-methyl-butyrate (beta-HMB), chromium, vanadyl sulfate, boron,
prasterone (dehydroepiandrosterone [DHEA]) and androstenedione] have
been purported to promote gains in fat-free mass during resistance
training. Most studies indicate that chromium, vanadyl sulfate and
boron supplementation do not affect muscle growth. However, there is
evidence that ingesting carbohydrate/protein prior to exercise may
reduce catabolism during exercise and that ingesting
carbohydrate/protein following resistance-exercise may promote a more
anabolic hormonal profile. Furthermore, glutamine, creatine, leucine,
and calcium beta-HMB may affect protein synthesis. Creatine and calcium
beta-HMB supplementation during resistance training have been reported
to increase fat-free mass in athletic and nonathletic populations.
HMB, or "beta-hydroxy beta-methylbutyrate", is a metabolite of
the amino acid Leucine and is produced naturally by the human body. HMB
is produced from a metabolite of leucine, called ketoisocaproate (KIC),
by the enzyme KIC-dioxygenase.
You may have first heard of HMB during the summer Olympics of 1996
when American swimmers were quoted in newspaper articles as saying,
"they had benefited from using HMB during their training".
Steven Nissen and his colleagues have performed the only study to
date of HMB on humans. The researchers agree that the mechanism by
which HMB impacts muscle proteolysis and function is not currently
known. Nevertheless there are a number of postulations. "The high
substrate concentration required by the dioxygenase enzyme compared
with the liver concentration of KIC suggests that HMB production in the
body may be a first-order reaction controlled by enzyme and KIC
concentrations. It has been calculated that, under normal conditions,
about 5% of leucine oxidation proceeds via this pathway. Therefore, if
humans are assumed to have enzyme actions similar to those seen in
pigs, a 70-kg human would produce from .2 to .4 g HMB/day depending on
the level of dietary leucine. At leucine intakes of 20-50 g/day (which
are used therapeutically), the concentrations of leucine and KIC in the
liver increase and could result in HMB production reaching gram
quantities per day". Some studies involving HMB supplementation to the
diet of steers and pigs have been shown to improve caracass quality.
Based on these findings, it has been hypothesized that supplementing
the diet with HMB may inhibit protein degradation during periods of
increased proteolysis such as resistance training.
Companies who promote the product claim that humans neither produce
enough HMB in their bodies, nor do they eat such HMB-containing foods
(e.g. catfish and grapefruit) regularly enough to provide the full
benefits of HMB. Researchers claim that when we input extra amounts of
HMB into our bodies the metabolite acts as a performance enhancer for
such activities as weight lifting and sprinting. In effect, companies
claim that HMB boosts strength levels, enhances gains in muscle size
and strength, and prevents post-workout muscle tissue breakdown. The
marketing companies do not make exactly clear how the product works,
but they have formulated a few widely accepted ideas which are seen on
the advertisement postings in many nutritional stores. Many of them
believe that excess amounts of HMB in the body cause an interference
with the body?s natural process of protein breakdown (particularly
after a workout).
Due to the fact that a limited number of HMB studies have been
performed on humans, we must also consider the results of the tests on
animals. Perhaps there is a connection between the noted improvements
in the two animal tests and those of humans. This data alone, however,
is insufficient. Since HMB is a relatively new product, one must take
into consideration the possible side effects or other negative aspects
of upsetting a natural balance within the body.
The patent for HMB use as a sport supplement is owned by Iowa State
University Research Foundation (ISURF) and has been licensed to
Metabolic Technologies, Inc. under U.S. patent number 5,348,979. If you
come across an HMB supplement that doesn't have this patent number on
its label, don't buy it. It's very likely fake. This does not mean that
an HMB product that doesn't have the patent number on the label is
certainly counterfeit. The current patents protect the nutritional uses
of HMB for promoting nitrogen retention and the explanation of those
methods. These "use" patents do not prevent others from manufacturing
HMB, it just prevents them from saying their products improve nitrogen
retention and muscle growth. However, because HMB is not a simple
nutrient to manufacture, in all likelihood any product that doesn't
have the patent #5,348,979 is fraudulent.
In terms of safety, a number of animal species have been fed large
amounts of HMB for varying periods of time. In all the animal studies,
there were no adverse effects or increases in death rates. When animals
were autopsied, there were no pathological changes in their organs or
tissues. Instead, the investigators found a lowered LDL (bad
cholesterol) response, increased immune function, fewer respiratory
illnesses, more lean body mass, and reduced fat mass. Even when pigs
were fed 100 times that used by humans, no problems occurred.
In human studies using 2-5 grams of HMB, blood chemistry, liver
function, and kidney function all remained normal. All the human
studies that looked at cholesterol found an average LDL decrease of 7%.
Nutritional strategies of overfeeding, ingesting
carbohydrate/protein before and after exercise, and dietary
supplementation of various nutrients [e.g. protein, glutamine,
branched-chain amino acid, creatine, leucine, beta-hydroxy
beta-methyl-butyrate (beta-HMB), chromium, vanadyl sulfate, boron,
prasterone (dehydroepiandrosterone [DHEA]) and androstenedione] have
been purported to promote gains in fat-free mass during resistance
training. Most studies indicate that chromium, vanadyl sulfate and
boron supplementation do not affect muscle growth. However, there is
evidence that ingesting carbohydrate/protein prior to exercise may
reduce catabolism during exercise and that ingesting
carbohydrate/protein following resistance-exercise may promote a more
anabolic hormonal profile. Furthermore, glutamine, creatine, leucine,
and calcium beta-HMB may affect protein synthesis. Creatine and calcium
beta-HMB supplementation during resistance training have been reported
to increase fat-free mass in athletic and nonathletic populations.
- Nic Vera. HBM: A Dietary Supplement for Building Muscle? Vanderbilt University
- Nissen
S; Sharp R; Ray M; Rathmacher JA; Rice D; Fuller JC Jr; Connelly AS;
Abumrad N, "Effect of Leucine Metabolite
Beta-Hydroxy-Beta-Methylbutyrate on Muscle Metabolism During
Resistance-Exercise Training" Journal of Applied Physiology (November
1996): 2095-2104 - Nissen and Abumrad, Nutritional role of
the leucine metabolite ß-hydroxy ß-methylbutyrate (HMB). J. Nutri.
Biochem. 8:300-311, 1997. - Kreider RB. Dietary supplements
and the promotion of muscle growth with resistance exercise. Sports Med
1999 Feb;27(2):97-110. Department of Human Movement Sciences and
Education, University of Memphis, Tennessee, USA.
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