The whole truth about creatine
Creatine (Cr) or methyl-guanide acetic acid is a compound formed in the kidneys and liver endogenously from the amino acids arginine and glycine using s-adenosylmethionine (SAMe) (1). 95% creatine in our body is found in skeletal muscle, small amounts ~ 5% in the brain and testes. 2/3 of intramuscular creatine is in the phosphorylated form, i.e. in the form of phosphocreatine (PCr), a compound that provides phosphate residues for the adenosine triphosphate (ATP) resynthesis. In the muscles we accumulate from 100 to 160 mmol creatine / kg dry muscle mass (2). About 1-2% of intramuscular creatine is degraded to creatinine (a metabolic by-product) and is excreted in the urine (2). Therefore, the body needs to supplement about 1-3 g of creatine per day to maintain normal creatine stores depending on muscle mass. Depending on the diet, a larger or smaller part of the daily demand for creatine may come from endogenous or exogenous sources, i.e. from diet (3).
In food, we find it mainly in meat and fish. 100 g of beef or salmon may contain approximately 500 mg of creatine (4). Interestingly, the highest content of creatine can be found in herring – 6.5 – 10 g / kg (4).
It has been found that some people have creatine deficiency of endogenous origin due to defects in AGAT, GMAT and / or creatine transporter (CRTR) enzymes, and therefore they must be dependent on creatine intake in the diet to maintain normal PCr and Cr concentrations in the muscles and brain (5). It has been reported that vegetarians have lower muscular creatine concentrations (90-110 mmol / kg of dry muscle) and therefore can observe better effects from supplementation (5, 6).
THE CREATINE FUNCTIONS
The primary role of creatine is to combine with the phosphoryl group to produce creatine phosphate in the creatine kinase reaction. In tissues and cells with high energy requirements (skeletal and smooth muscles as well as brain, sperm and photoreceptor cells), the concentration of phosphocreatine far exceeds the ATP concentration. During activation of the cell, the creatine kinase from the phosphocreatine stores regenerates ATP, which is the main source of energy in biochemical reactions. This helps to maintain the availability of ATP, especially during anaerobic maximal effort.
The CK / PCr system also plays an important role in the transfer of intracellular energy from the mitochondria to the cytosol. CK / PCr energy transfer combines ATP production sites (glycolysis and mitochondrial oxidative phosphorylation) with ATP (ATPase) sites. In the cytosol, creatine and its associated cytosolic and glycolytic CK isoforms allow to maintain energy balance. In addition, creatine diffuses into the mitochondria and combines with ATP produced from oxidative phosphorylation and an adenine nucleotide translocator (ANT) through the mitochondrial CK. ATP and PCr can then diffuse back into the cytosol and help meet energy needs. This coupling also reduces the formation of reactive oxygen species (ROS), and thus can act as an antioxidant. In this way, the CK / PCr system serves as an important regulator of metabolism that can help explain the ergogenic and potential therapeutic health benefits of creatine supplementation (7).
Creatine can buffer pH changes that result from the accumulation of hydrogen ions as a result of physical exercise, thanks to their use in the creatine kinase reaction. The anabolic effect of creatine on muscle can be associated with its muscle-lifting properties of IGF-1 muscle mRNA (9). Creatine can affect the expression of genes in skeletal muscle, which can be an independent mechanism conditioning its ergogenic effect (29).
Athletes of many disciplines effectively use creatine primarily to improve athletic performance and training adaptation and the increase of lean body mass. (31)
WHICH FORM OF CREATINE SHOULD YOU CHOOSE?
The best-studied form of creatine is monohydrate. It has never been proven that another form is more effective in increasing muscle creatine concentration. Absorption of creatine is nearly 100% and its conversion to creatinine during digestion is negligible. Plasma creatine concentration usually reaches a peak of about 60 min after oral ingestion of creatine monohydrate. Degradation of creatine to creatinine can be reduced or stopped, either by lowering the pH below 2.5 or by increasing the pH (8)
In people who are on a standard diet, which accounts for about 1-2 g of exogenous creatine per day, creatine stores in muscle are saturated in about 60-80%. To increase the concentration of this substance in the body, supplementation should be used. To this end, you can use the following protocols:
- The most effective way to increase creatine concentration in the muscles in a short time is to consume 5 g (or about 0.3 g / kg body weight) four times a day for 5-7 days (2, 10).
- When creatine stores in muscle are saturated, you can maintain its level by taking 3-5 g / day, although some studies indicate that a larger number of athletes may need up to 5-10 g / day to maintain creatine stores (2, 10 , 11, 12).
- Doses of 3-5 g without the “saturation phase” will saturate creatine stores to a similar level within 4 weeks (2). So here everything depends on the expected rate of increase in the concentration of this substance in the muscles.
- Studies have shown that after reaching the maximum concentration of creatine in muscles the washout to the level before supplementation usually takes 4-6 weeks (2, 12, 13). After the washout period, the level of creatine stabilizes at the level of the input concentration and does not fall below its value.
- In order to increase creatine concentration in the brain, reduce the effects of creatine deficiency or to achieve a therapeutic effect in disease states a longer period of supplementation is required (14)
- In addition, due to health benefits, it is recommended to consume about 3g per day of creatine in your diet. In particular, in people who are aging in order to minimize the risk of the appearance of aging symptoms, eg sarcopenia (7).
- In order to optimize the transport of creatine to muscle cells and to improve the rate of resynthesis of muscle glycogen, you can combine creatine with carbohydrates. In a study by Green et al. Simultaneous intake of 5 g of creatine with 95 g of glucose increased the creatine absorption by muscle cells (11). In the Steenge et al study, simultaneous intake of 5 g creatine with 47-97 g of carbohydrates and 50 g of protein increased the creatine retention (15). Nelson and colleagues have proved that loading creatine before carrying out exhaustive training and loading carbohydrates promotes more effective glycogen restoration than just carbohydrate loading (16).
WHO BENEFITS FROM SUPPLEMENTATION?
The creatine supplementation will benefit primarily athletes of disciplines, in which phosphagen energy conversion prevails, eg running sprints and swimming sprints, weight lifting. Contrary to conventional theories, the benefits are noticed not only by athletes in short-term maximum efforts, but competitors of many disciplines (1):
- Athletes of team sports and other start-stop sports mainly due to the more effective resynthesis of PCr
- Athletes of anaerobic sports, in which the limiting factor is the accumulation of hydrogen ions in the muscles, e.g. runners 400-800 m, swimmers 100-200 m, combat sports athletes
- Athletes who needs to increase lean body mass, e.g. american football players, bodybuilders, weight lifters, rugby players
- Endurance athletes, eg long-distance runners, swimmers, triathletes
THE HEALTH BENEFITS OF CREATINE
Athletes exploit the benefits of creatine associated with its impact on the support of energy pathways, the development of musculature. They are not the only benefits caused by its supplementation. There are at least a few other reasons why it is worth to supplement creatine:
- It can reduce muscle damage and / or improve recovery after intense physical exercise (17, 18, 19, 20).
- Probably can play an important role in the prevention of injuries to the musculoskeletal system (21, 22).
- It can have a positive effect on muscle loss rates due to limb immobilization or during rehabilitation (23, 24, 25).
- Studies on an animal model prove the usefulness of creatine in the support of TBI therapy and brain and spinal cord trauma (26). There is evidence that increased creatine levels in the brain may be effective in reducing or curing post-traumatic brain injury, but only limited data from human studies are available to verify this hypothesis, which is an exciting area for further study. (27) This is another reason why creatine supplementation is worthwhile for combat sports athletes.
- It can have a positive effect on thermoregulation and “performance” during high-temperature efforts (28).
- Creatine supplementation may be beneficial during pregnancy, during aging in the prevention of sarcopenia and support of cognitive abilities, in the support of ischemic heart disease therapy, neurodegenerative diseases and genetic deficits in creatine synthesis. (1)
Available short- and long-term studies in healthy and clinical populations, from infants to older people, have proven that creatine supplementation at doses of 0.3 to 0.8 g / kg bw daily for up to 5 years does not pose a health risk and may provide a number of health benefits. Clinical populations have been supplemented with creatine monohydrate (0.3 – 0.8 g / kg / day, equivalent to 21-56 g / day for a 70 kg individual) over years without clinically significant or serious adverse events. It is worth paying attention to the temporary increase in body mass attributed to the increase of muscle fluid content in the muscles, which may adversely affect the result in sports, in which the ratio of body weight to strength is significant (eg climbing) and in athletes of disciplines in which weight categories apply ( e.g. martial arts). In order to reverse the effects of long-term creatine supplementation in the context of weight gain, it is worth considering stopping supplementation about 4-5 weeks before the pre-competition weighing procedure with regard to the duration of the washout.
COMMON MYTHS RELATED TO CREATINE
There have been many myths around creatine supplementation. I decided to recall and dispel the most frequently repeated myths:
- “… Creatine increases the risk of injury and damages the kidneys …” Creatine does not increase the risk of injury, muscle contractions or adversely affect kidney function (1). Due to single cases of deterioration of health and increase in creatinine level in patients with renal insufficiency after supplementation with creatine (against many trials in which no harmfulness has been proven), it is worth not risking supplementation in patients with known insufficiency of this organ. It is also worth not risking patients with advanced hypertension.
- “… I will hold on the water after the monohydrate, I will not hold it after other forms of creatine …” Any form of creatine increases the level of creatine in muscles, however the most effective form is monohydrate. Maybe because it contains the most creatine in the product and is characterized by high bioavailability and is the most frequently used form of creatine by users, it is reported by water retention most often by users. Any form of creatine can cause weight gain associated with greater hydration of muscle cells.
- “… Creatine causes dehydration and electrolyte disturbances during exercise …” Studies show that creatine can even increase the tolerance of exercise at high temperatures.
- “… Alternative forms of creatine (malate, hydrochloride, nitrate, phosphate, kre alkalyn or others …) are better than monohydrate …”. It has not yet been proven that any other form of creatine is better than the monohydrate.
- “… Only athletes who are dominated by phosphagen transformations will benefit from creatine supplementation …” This is not true, because athletes of other disciplines such as start-stop sports will also benefit from creatine supplementation due to faster resynthesis of PCr and even endurance sports thanks to better transport of energy from the mitochondria to the cytosol. In addition, in endurance athletes, after the creatine supplementation, you can notice an increase in “performance” during high intensity stages (eg uphill climbs in cycling, sprints at the end of the marathon) (30).
- “… Creatine should be taken before training …” In the study, Antonio et al. Showed that people who received creatine after training achieved better increases in lean body mass and muscle strength from those taking it before training. (32) It does not really matter when you take creatine. Its effects are associated with accumulation in muscle tissue. Creatine does not have immediate effects such as caffeine. Considering the fact that the transport of creatine to the muscles is positively influenced by insulin and taking into account that carbohydrates and protein intensify the secretion of the above-mentioned It would be good to take a hormone, creatine, with meals, for example with pre-workout and post-workout meals. Although it must be borne in mind that in practice it will have a rather minor effect on the effectiveness of supplementation.
- “… Creatine can be taken for a maximum of 8 weeks …” There is no scientific evidence that long-term or even permanent supplementation with creatine can be harmful. Loading huge doses over a longer period of time, however, seems to be pointless. After reaching the maximum concentration of creatine in the muscles it is worth maintaining its level with a maintenance dose or stopping the supplementation to achieve rinsing.
Creatine remains one of the few dietary supplements for which consistently conducted studies show ergogenic benefits in many sports. In addition, creatine supplementation brings many potential health benefits, is safe and well tolerated by most people. In contrast to many of the dietary products offered by the industry with dubious use, the purchase of creatine is a well-invested money in health and sports form.
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