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Supplements: Muscle/Strength/Power/Recovery
This category is often filled with products that offer
high promise and little delivery. Only a scant few actually warrant consumption
by most fitness enthusiasts, with creatine and glutamine
topping this short list. Both have been research-tested as well as anecdotally
shown to improve performance and recovery.
What is Creatine?
Creatine is made up of the three amino acids:arginine,
glycine and methionine. Our body produces creatine in the liver and at
any given time the average person has about 120 grams of creatine stored
in their body. Creatine is an essential, natural substance required for
energy metabolism, muscular movement and human existence. Creatine is
as essential to life as protein, carbohydrates, fats, vitamins and minerals.
Creatine deficiencies have been associated with certain physical-muscular
disorders that can be fatal in humans and animals.
The human body synthesizes creatine from 3 amino acids:
glycine, arginine, and methionine.
These amino acids are components of protein. In humans, the enzymes involved
in the synthesis of creatine are located in the liver, pancreas and kidneys.
Creatine can be produced in any of these organs and then transported into
the muscle via the bloodstream. Approximately 95% of the total creatine
pool is stored in skeletal muscle tissue. The remaining 5% can be found
in the heart, brain and testes. As stated earlier, it is estimated that
a 70 kg (154 lbs.)
male will have a total creatine pool of approximately 140 grams in his
body. The total creatine pool in humans refers to the combined amount
of creatine in its free form and phosphocreatine form. In skeletal muscle
tissue, phosphocreatine accounts for two-thirds of the total creatine
pool, with free form creatine making up the balance. In the absence of
exogenous (from the diet) creatine, the rate of creatine excreted in the
form of creatinine has been estimated to be around 1.6% per day in humans.
Thus, with a bodyweight of 70kg (154 lbs.) and a total creatine pool of
140 grams, a human will lose approximately 2 grams of creatine per day
from normal everyday activity. This turnover of creatine will increase
with greater physical activity and must be replaced by the diet or the
body's own natural production. Dietary creatine is found mostly in meat,
fish and other animal products. Plants contain only trace amounts. The
average daily diet of meats and vegetables contains an estimated creatine
level of 1 gram. As only some of the daily requirement of creatine can
be attained from diet, the body must synthesize the rest. A vegetarian's
daily requirement for creatine can only be achieved by endogenous (from
within the body) synthesis via the enzyme GAMT. The effect of aging on
the level of free form creatine and phosphocreatine has been studied by
Moller and colleagues at the Karolinska Institute in
Stockholm. Interestingly, there were no differences in the total creatine
levels between a group of elderly (aged 52 to 79) and young (aged 18 to
36). But the
study did reveal that the younger participants had higher phosphocreatine
levels than did the older group. Such differences can be attributed to
the greater
level of activity in the younger group.
Creatine provides energy for your muscles
In your body you have an energy containingcompound
called ATP (adenosine tri-phosphate). What is important to knowabout
ATP is that the body can very quickly get energy from a ATP reaction.
You have other sources of energy such as carbohydrates and fat - but they
take
longer to convert into a useable energy source. When you are doing an
intense quick burst activity such as lifting a weight or sprinting, your
muscles use ATP
for a quick burst of energy. In order for ATP to release its energy it
must give up a phosphate molecule and become ADP (adenosine di-phosphate).
Unfortunately, we do not have an endless supply of ATP. In fact, your
muscles only contain enough ATP to last about 10-15 seconds at maximum
exertion. Here is where the creatine comes in to play. When creatine enters
the muscles it bonds with a phosphate and becomes creatine phosphate (CP).
CP is able to react with the ADP in your body and turn "useless"
ADP back into the "super useful" energy source - ATP. More ATP
in your body means more fuel for your muscles.
This is the process by which creatine provides more energy for your muscles.
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Glutamine (Amino Acid)
Glutamine is not found in food. It is primarily a brain
fuel which can take the place of glucose. It is particularly abundant
in the substania nigra and thalamus of the brain, as well as in the blood,
where its concentration is three to four times greater than all other
amino acids. It is 10 to 15 times more concentrated in the cerebrospinal
fluid than in the blood. In fasting or starvation states, when glycogen
stores have been exhausted, large amounts of glutamine (and alanine) are
released from muscle tissue and serve to shuttle amino acid nitrogen and
carbon to other tissues. The carbon may be converted to glucose by the
liver and made available for energy production.
Glutamine also performs a major role in DNA synthesis. An influx of large
amounts of glutamine may stimulate muscle protein synthesis. 60 per cent
of the ammonia produced in the kidney tabules to buffer excessive urinary
acidity comes from the breakdown of glutamine.
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