Creatine: What You Need to Know
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The latest craze among athletes and bodybuilders across America is a supplement called creatine. Creatine is found naturally in the body and can also be obtained through food and supplements. Supporters of creatine supplementation maintain that it increases strength, performance, and
muscle mass. However, because of the long-term effects of creatine are not known,
many people are wary of its use.
So what exactly is creatine, how does our body use it, and how do
supplements assist in achieving muscular strength and size? Creatine is a
nitrogenous substance synthesized mainly by the liver and to a much lesser
extent by the pancreas and the kidneys, at a total rate of approximately
1-2g a day. The amino acids arginine,glycine, and methionineare combined by
these vital organs to form creatine. After synthesis, creatine is carried
by
the bloodstream to the skeletal muscle cells, where specific protein
transporter molecules carry it directly into the muscle until it is needed
for energy. Most of the creatine that is taken up by the muscle is
converted
into phosphocreatine.
During high-intensity, short duration exercise, the
amount of energy supplied is determined by the amount of phosphocreatine
stored in the skeletal muscle. As phosphocreatine stores become depleted,
fatigue will ultimately occur, reflecting an inability to resynthesize ATP,
the primary fuel for muscle, at the rate required. Therefore, it has been
presumed that increasing muscle creatine content may increase the
availability of phosphocreatine and allow for a quicker rate of resynthesis
of ATP during and following brief, high-intensity exercises.
Additional creatine is supplied to the body through protein-rich sources,
particularly beef, pork, herring, tuna, and salmon. Generally, a mixed diet
provides about one gram of creatine each day. Creatine supplements are yet
another form of acquiring creatine. This pill form is preferred by many
supplement users because of the high fat content of most food sources. In
order to receive the 20 g of creatine recommended as a loading dose by
manufacturers, one would have to consume 10 pounds of raw steak.
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