This article covers all the questions to be asked about creatine.
WHAT IS CREATINE ?
Creatine is a nitrogenous organic compound synthesised mainly by the kidneys, liver and pancreas, from non-essential amino acids.
The body contains about 120g of creatine for a 70kg man and 95% of this body creatine is stored in the muscles. Creatine synthesis is adjustable, especially when your food intake is low: it is able to supplement it, so that creatine levels in the body are always maintained. This phenomenon ensures a stable creatine level. Thus, even non-meat eaters have a stable creatine level and all the creatine needed for the proper functioning of the body.
WHAT ARE THE CREATINE REQUIREMENTS ?
The creatine requirements are 2g per day for the general population, but you need to add 1 to 2g per day for athletes with strong muscle mass during intense training.
Specifically, there is no recommended dietary intake, since creatine can be synthesised by the body and perfectly responds to needs, especially for strength or muscle development athletes who benefit from appropriate protein intake.
HOW DOES THE CREATINE WORK ?
Creatine in the body circulates in the blood to reach the storage organs, such as the muscles. It is then transformed into a compound called "creatine phosphate" (CP). It is a tiny source of energy, whose life is just a few seconds. CP is very useful at the start of exercise, and is of very strong intensity but very brief and transitory. CP also restores reserves of ATP, the energy molecule that provides the power required for muscle contraction.
SHOULD CREATINE BE PROVIDED THROUGH DIET ?
Creatine intake varies considerably according to nutritional balance. Meat, poultry and fish are products rich in creatine: they contain about 4 to 5g of creatine per kg of product. On the contrary, milk contains just 0.1g per litre of creatine.
For example, with vegans, the dietary intake of creatine is virtually non-existent, so creatine will be synthesised entirely by the body. Indeed, whatever the diet, no deficiency has been described.
IS THERE ANY BENEFIT IN SUPPLEMENTING CREATINE INTAKE ?
CP concentration is 3 to 5 times higher than that of ATP in muscle. In terms of available energy, it is more ephemeral than the energy provided by carbohydrates, and this phenomenon is even more true compared to the energy provided by lipids.
The energy reserves in creatine are therefore theoretically less attractive compared to those of other nutrients.
All the benefit of creatine lies in its almost immediate availability at the start of exercise compared to other energy sources whose availability is delayed over time.
During supplementation with creatine, synthesis by the body decreases very clearly and would be completely reversible within 4 weeks of stopping supplementation. The benefit of supplementation is therefore highly debatable. Ingested creatine is added to that in the diet but replaces that synthesised by the body, which is then inhibited. The benefit is therefore very low...
CAN CREATINE PLAY A ROLE IN SPORT ?
The athlete’s body does not express a significantly increased need for creatine and there is no nutritional type of advice: diet and endogenous synthesis alone can meet the needs of the body without a deficiency or even pre-deficiency being observed in the athlete. Any exogenous supply of creatine then comes from supplementation, beyond the physiological needs.
One of the main benefits of creatine supplementation lies in increasing its content in muscle, with the effect of increasing the anaerobic alactic capacity (procedure for short and intense exercise). This makes it possible to train at very high intensity, a little longer, and to postpone the time when the source is exhausted. It must be emphasised that these are very brief exercises, 15s maximum. Then the anaerobic lactic channel takes over with available muscle energy content 300 times higher than that of CP.
In concrete terms, it is not a question of "repelling fatigue" by creatine ingestion, but is rather about delaying the time of exhaustion during very brief, repeated and intense exercises, like sprints, weightlifting movement or repeated throwing.
Unfortunately, the term "fatigue" is often misused, which can mislead the consumer.
WHAT ARE THE HEALTH EFFECTS OF CREATINE SUPPLEMENTATION ?
Muscle cramps have been described on several occasions under the effect of dehydration in a hot thermal environment.
Accusations made against creatine with regard to its possible harmful effects on health most often relate to renal functions. Extensive investigations have been performed following creatine ingestion. The authors believe that it is necessary, prior to any supplementation, to carry out an anamnesis of athletes thought to be in good health, in order to detect any renal damage, even minor. These examinations should be repeated regularly (every 3 months) during the supplementation period. Any pathological effect should imperatively result in supplementation being stopped.
WHAT PRECAUTIONARY PRINCIPLE HAS BEEN ADOPTED FOR CREATINE SUPPLEMENTATION ?
Clearly, whatever the creatine supplementation, in high quantity, loading dose or chronic condition, in the short, medium or long term, the deleterious effects and potential risks are poorly understood today.
It therefore seems necessary to be vigilant about this product, which has certainly demonstrated positive effects on certain performance results, but which remain specific cases. Many claims far exceeded what the scientific facts have shown, highlighting that this is a product with effects which are still poorly understood.
IN WHAT FORM CAN CREATINE BE FOUND ?
Commercially, creatine generally comes in powder form, but it is also found in the form of tablets, gel, syrup and drinks. It comes either alone or associated with carbohydrates or proteins, vitamins, minerals or amino acids.
Some of the claims mention the greater effectiveness of powder for strength sports and tablets for endurance sports, but so far, no scientific study has justified these remarks. We must therefore remain vigilant about the various promises of power and performance, which are often unjustified.
CREATINE : WHAT IS AFSSA'S ADVICE
• we should remember the importance of a balanced and diversified diet and appropriate hydration, adapted to the specific needs of the athlete in accordance with the recommendations of the recommended nutritional intake (RNI);
• creatine is provided through the diet or produced by endogenous synthesis in sufficient quantity to meet physiological needs, without any deficiency being described and without it having appeared necessary to establish a recommended nutritional intake;
• with creatine supplementation, the increase in body weight and muscle mass are always less than 3% and 10%, respectively, and are mainly due to water retention and not protein synthesis;
• all claims, in particular those concerning strength, speed or maximum power, tests, exercises or performance in the anaerobic lactic (anaerobic glycolysis) or aerobic systems, lactatemia, ammonia levels, protein synthesis, fatigue motivation, tone, fitness or aggressiveness do not currently benefit from recognised and validated scientific work and are therefore unfounded;
• the only claims that benefit from significant scientific work but show inconsistent results are repeated, high-intensity exercises lasting 15 seconds or less;
• use of creatine supplements presents a risk which is today insufficiently evaluated, in particular for long-term use, in terms of the health of the consumer with a potential carcinogenic risk;
• regular reassessment requiring the use of scientific studies is essential, both in terms of the effects on health and on performance.
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