Nutritional Advice El Mondo-
Creatine (a-methyl guandino-acetic acid) plays an important role in rapid energy provision during muscle contraction involving the transfer of N-phosphoryl group from phosphorylcreatine (PCr) to ADP to regenerate ATP through a reversible reaction catalyzed by phosphorylcreatine kinase (PCK).
ATP + creatine =======> PCr + ADP + H+. - Phosphocreatine (PCr) is a major source of muscular energy during short-term, high-intensity exercise bouts lasting from approximately 2 to 30 seconds.
- Dietary intake and endogenous production of creatine matches the spontaneous degradation of phosphocreatine (PCr) and creatine to creatinine at a rate of 2.6% and 1.1% per day, respectively. That is about 1-2 grams creatine per day.
- Meat and fish are major dietary sources of creatine.
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Creatine is obtained through the diet (1 g/day for an omnivorous diet) and synthesized in the liver, kidney and pancreas (1 g/day).
Synthesis predominately occurs in the liver, kidneys and to a lesser extent in the pancreas. - Three amino acids (glycine, arginine and methionine) and three enzymes (L-arginine:glycine amidinotransferase, guanidinoacetate methyltransferase and methionine adenosyltransferase) are required for creatine synthesis.
- The majority of creatine in the human body is in two forms, either the phosphorylated form making up 60% of the stores or in the free form which makes up 40% of the stores.
- Creatine is distributed throughout the body with 95% of creatine found in skeletal muscle. The remaining 5% of the creatine pool is located in the brain, liver, kidney and testes.
- The average 70 kg young male has a creatine pool of around 120-140 g.
- One beneficial effect of creatine supplementation in young, healthy males is enhanced muscle fiber size and increased lean body mass.
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Creatine supplementation can be divided into loading and maintenance phase.
In loading phase, 20-30 grams creatine per day, regardless of body weight, or 0.3 grams per kilogram body weight and divided into four taking 5-7 grams each time, about 3-4 hours apart for 5-7 days continuously.
In maintenance phase, 2-3 grams creatine per day, regardless of body weight, or 0.03 grams per kilogram body weight for 4-10 weeks in a row.
Other supplementation protocols are also used such as a daily single dose of around 3-6 g or between 0.03 to 0.1 g/kg/d. However, this method takes longer (between 21 to 28 days) to produce ergogenic effects. - The total body content of creatine increases from 17 to 20% with a dosing regimen of 20 to 30 g for 2 or more days.
- Only 80% responds to creatine supplementation. Responders are those individuals with a lower initial level of total muscle creatine content, greater population of type II fibers and possess higher potential to improve performance in response to creatine supplementation.
- Side effects from creatine supplementation have been reported as typically weight gain between 1 and 2 kg and is initially brought on by water retention, but may be maintained by changes in amount of lean body mass.
- Creatine ingested through supplementation is transported into the cells exclusively by CreaT1.
- Creatine monohydrate is the most effective ergogenic nutritional supplement currently available to athletes in terms of increasing high-intensity exercise capacity and lean body mass during training.
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EFSA has approved the following creatine-claim:
- Creatine increases physical performance in successive bursts of short-term, high intensity exercise at a daily intake of 3 grams. In Europe, only approved claims of EFSA are allowed on packaging of foods or dietary supplements.
Scientific studies on the relationship between creatine and disease prevention or sport performance:
Review articles of randomized, placebo-controlled double-blind clinical trials (RCTs) will answer the following question:
"Is taking dietary supplements make sense?". Yes at a positive conclusion and no at a negative conclusion.
Review articles of cohort studies or case-control studies will answer the following question:
"Should I change my diet?".