# supplements FAQ's



## jack hust (Dec 19, 2003)

supplements FAQ's 
supplement FAQ

creatine :
Creatine Background
1. What is creatine?
2. How does creatine work?
3. How can I get creatine naturally?
4. How does creatine get into muscle?
5. Do all muscles respond the same to creatine? 
6. Does everyone respond to creatine? 




1. What is creatine?
Creatine is something that the body normally contains. The body either produces it naturally (see Question #3), or it is obtained directly from the foods we eat (see Question #3). On average the body goes through about 2 grams of creatine each day.

Most of our body's creatine is contained within skeletal muscle, although some is also present in the heart, brain and testes. Following ingestion (or synthesis) creatine is transported into our muscles (see Question #4) where it serves to increase muscle energy levels. Creatine achieves this by increasing the availability of ATP, the cell's energy molecule (see Question #2).

Recently it has become popular to supplement one's diet with synthetically produced creatine in hopes of enhancing athletic performance. Synthetic creatine is sold as citrate, phosphate or monohydrate salts. Creatine monohydrate is the most commonly used form in athletics and is nothing more than a molecule of creatine accompanied by a molecule of water. A gram of creatine monohydrate contains more creatine than a gram of either creatine citrate or a gram of creatine phosphate.

We typically notice an improvement in exercise performance when our muscle creatine levels increase by at least 20% as a result of creatine supplementation (see Question #6).






2. How does creatine work?
Simply speaking, creatine increases the energy content of muscle cells. Creatine does this by increasing the availability of ATP, the energy currency of cells. Since our strength depends on how quickly ATP can be made available during exercise, creatine supplementation increases our strength. Return to top





3. How can I get creatine naturally?
In one form or another, creatine is normally obtained from the foods we eat.

Dietary Creatine: Creatine can be directly obtained by eating sources of skeletal muscle, ie meat and fish. During the digestive process the creatine contained within meat and fish is directly released into the blood stream where it is transported to skeletal muscle. For reference, approximately 2-3 pounds of raw meat or fish contain the equivalent of 5 grams of pure creatine monohydrate powder. (see Question #7) Since heat degrades creatine, however, cooking reduces the creatine content of meat and fish. Therefore, you'll need to eat more cooked meat to get the same amount of creatine as from uncooked sources.

Creatine Synthesis: When dietary creatine intake doesn't meet the body's needs, new creatine can also be synthesized from three amino acids; arginine, glycine and methionine. These amino acids are made available during the digestion of foods. Importantly, methionine availability sets an upper limit on creatine synthesis, since the body can not produce it on its own. Methionine must, therefore, be provided in our diets.

Since fish is one of the richest natural sources of methionine, eating fish provides both a direct source of creatine as well as an adequate supply of dietary methionine for new creatine synthesis.

Vegetarians: Vegetarians, whose animal protein intake is low, typically express lower than "normal" creatine levels. Creatine might therefore be advisable for athletes who purposefully restrict their animal protein intake.



4. How does creatine get into muscle?
From the blood creatine is transported into skeletal muscle by special transporter molecules on the muscle surface. The activity of these creatine transporters is influenced by the availability of creatine. For example, elevated plasma creatine interrupts creatine uptake into skeletal muscle via these transporters. The new production of creatine from amino acids is also stopped by elevated plasma creatine. These are examples of normal feedback regulatory processes that are common in biology. However, how exogenous creatine supplementation influences these processes in humans is still an open issue. This is why it is often recommended to periodically stop taking creatine to let the body recuperate (see Question #7).

Transporter function is also regulated by other physiological processes. For example, creatine transporter activity is enhanced by co-ingestion of highly glycemic foods, an effect mediated by insulin release. Therefore, taking measures to improve one's insulin sensitivity should enhance creatine uptake into skeletal muscle. 


5. Do all muscles respond the same to creatine?
Not all muscle types respond equally to creatine supplementation. Muscles can be loosely described as either fast or slow. As the name implies, fast muscle fibers mediate abrupt movements. Fast muscle fibers are also those that predominantly use creatine energy production. Hence, explosive movements respond best to creatine supplementation.

Slow muscle fibers, on the other hand, do not rely that heavily on creatine energy production. Slow muscle fibers are also those that play an important role during endurance exercise. It follows that endurance tasks are influenced less by creatine supplementation. In addition, many endurance sports may be adversely effected by the increase in weight associated with creatine supplementation.

6. Does everyone respond to creatine?
Not everyone responds to creatine supplementation. It is estimated that 20-30% of the population are nonresponsive to creatine use. This isn't to say that many "nonresponders" couldn't convert to "responders" given the right circumstances. Taking creatine with highly glycemic sugars helps in many instances.

It is also important to note that persons with naturally high creatine levels typically benefit less from creatine supplementation. Furthermore, the benefits your percieve from creatine use depend on the exercise task being used to measure its effectiveness (see Question #5). There is also some indication that creatine may be less effective in children and the elderly. (see Question #10) Finally, simple, every day, dietary habits, such as alcohol and caffeine consumption, can profoundly influence creatine's effectiveness.

covers creatine.


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