Creatine Information
Creatine is found in amino acids (glycine, arginine,
and methionine). It is synthesized from these amino acids
in the liver, pancreas and kidneys. Muscles take up the
majority of the creatine found in the body. It is in the
muscle that creatine is converted to phospocreatine, which
is necessary for ATP production. Research shows that
taking creatine supplements can increase muscle creatine
by 20 to 30%. Increasing the amount of creatine found in
the muscle also increases the amount of phosphocreatine,
which aids in producing greater amounts of energy. This is
because phosphocreatine is the limiting factor in energy
production in high intensity anaerobic exercise. Thus, it
is believed that supplementing the body with creatine
enhances athletic performance.
What Does the Research Show?
Creatine has been shown to be effective only in certain
instances, and not necessarily to the degree often
advertised. Several studies suggest that creatine enhances
performance in activities involving repeated short periods
of intense activity. Supplementing creatine in the correct
dosage with the proper duration can aid in improving
athletic anaerobic performance (weight lifting, sprinting,
rowing). However, creatine supplementation does not
benefit endurance athletes -- marathon runners for
example.
Sprinters who loaded with Creatine (25 grams for 5 days)
significantly increased their peak and average sprint
power output compared a group taking an inactive placebo.
NCAA division 1A football players who took creatine
supplements for 28 days during the off season experienced
gains in total body mass, and increased their weight
lifting ability. They also had faster sprint times than
players in a control group who did not take creatine. Male
rowers who took 20 grams of creatine for 5 days
significantly increased their rowing times. But not all
studies find significant improvements in performance
attributable to creatine. In another study of competitive
rowers, those who were supplemented with .25 grams per kg
of body weight had faster times, but the increase was too
small to be considered statistically significant.
Marketing claims that creatine increases muscle mass are
controversial. Research has shown that people who
supplement with creatine do gain weight. However, more
research is needed to assess how much of the weight gain
is actually due to increased muscle mass.
Currently there is no evidence that creatine increases fat
metabolism.
Some studies have shown that people suffering from
neuromuscular disease or from congestive heart failure may
improve muscle strength by taking creatine. However, more
research is needs to be done in this area to confirm these
findings. Preliminary research investigating the potential
benefits of creatine for the elderly, found no difference
in strength or body composition in people who were
supplementing with creatine. It is recommended that any
elderly person who elects to take creatine have their
renal (kidney) function periodically.
How Much Creatine is Safe?
Since creatine is a supplement and produced naturally in
the body, the Food and Drug Administration (FDA) does not
currently have dosing standards. Taking a dose of 20 grams
a day for one week, followed by 2-5 grams as a daily
maintenance dose has not been shown to have adverse
effects. However, people who exceed this dosage may be at
a higher risk of developing renal disease.
People who currently suffer from renal disease should not
take creatine. The consumption of creatine right before or
during exercise is not recommended. It may be beneficial
to increase fluid consumption when taking creatine to
prevent dehydration. Caffeine may negate the benefits of
creatine by inhibiting phosphocreatine resynthesis, which
takes place in the recovery phase of exercise.
Creatine can also be obtained from eating a mixed diet.
Animal products such as herring, pork, salmon, beef, cod
and milk contain creatine naturally. Normally people
ingest about 1 gram a day of creatine from their diet.
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