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Hier ein Link zu einem Artikel über Kreatin aus der Onlinezeitschrift Men's Health auf Englisch. Da ich nicht weiß, wie lange dieser Artikel online verfügbar sein wird, habe ich ihn hierher kopiert. Hier der Originallink: http://www.menshealth.com/supplements/articles/The_Facts_About_Creatine.php
The Facts About Creatine
Everything you need to know about creatine. Is it safe? Are there side effects? Just what is creatine, anyway? Men's Health has the answers
Jamie Bellavance
Richard Kreider, Ph.D., chairman of the Department of Health, Human Performance and Recreation and Director of the Exercise and Sport Nutrition Laboratory and Center for Exercise, Nutrition & Preventive Health Research at Baylor University, answers your most common questions about creatine supplementation.
Dr. Kreider has published more than 300& sport nutrition articles and abstracts that are published in scientific journals. He is also a Fellow of the American College of Sports Medicine, Fellow of the International Society of Sport Nutrition, and editor-in-chief of the Journal of the International Society of Sport Nutrition.
1. Are there any side effects to creatine?
The only significant side effect that has been consistently reported in scientific and medical literature has been weight gain. However, there have been a number of reported side effects such as stomach problems, muscle cramping, dehydration, and increased risk of muscle strains/pulls. There has also been concern that short and/or long-term creatine supplementation may increase renal (kidney) stress.
One research group suggested that creatine supplementation may increase an individuals risk to developing anterior compartment syndrome (ACS). Over the last few years a number of studies have indicated that creatine is not associated with any of these reported problems nor increase the likelihood of development of ACS. In fact, there is recent evidence that creatine may lessen heat stress and reduce the susceptibility to musculoskeletal injuries among training athletes.
While people who take creatine may experience some of these problems, incidences in creatine users aren't greater than subjects who take placebos and in some cases are less.
2. What is the best form of creatine to take?
Nearly all studies on creatine supplementation have evaluated pharmacological grade creatine monohydrate in powder form or have used oral or intravenous phosphocreatine formulations (a more expensive form of creatine).
Since creatine has become a popular supplement, there are a number of different forms of creatine that have been marketed (e.g., creatine candy/bars, liquid creatine, creatine gum, creatine citrate, effervescent creatine, etc). Many of these forms of creatine claim to be better than creatine monohydrate. However, no data indicates that any of these forms of creatine increases creatine uptake to the muscle better than creatine monohydrate.
The only potential benefits of these different forms of creatine are convenience, supplement variety, and/or taste preferences. The greatest disadvantage, however, is that many of these supplements are more expensive than creatine monohydrate. There is absolutely no evidence that you can take less of these types of supplements (e.g., liquid creatine or effervescent creatine) and get the same benefits than ingesting higher amounts of creatine monohydrate because of less breakdown in the stomach, greater intestinal absorption, faster absorption in the blood, and/or greater muscle uptake.
The best raw sources of creatine monohydrate are from Germany (e.g., Degussa’s CreaPure™) or the U.S. (e.g., Ferro Pfansteihl). Care should be taken to only purchase high quality creatine monohydrate that is produced in inspected facilities that adhere to FDA good manufacturing practice guidelines.
Editor's Note: We found another Creighton University study that found that creatine phosphate (Mega Creatine at gnc.com) improved performance three times as well as creatine monohydrate. The reason: Extra phosphate helps delay the onset of fatigue, says Joan Eckerson, Ph.D., C.S.C.S., the study's lead author.
3. Should athletes load or not load?
Research has shown that the most rapid way to increase muscle creatine stores is to follow the loading method, by taking 0.3 grams/kg/day of creatine monohydrate for 5 to 7 days (e.g., 5 grams taken four times per day). Studies show that this rate can increase muscle creatine. Once muscle creatine stores are saturated, studies indicate that you only need to take 3 to 5 grams of creatine monohydrate per day in order to maintain elevated creatine stores.
Most of the creatine is taken up by muscle during the first 2 to 3 days of the loading period. While there is one study that suggests that taking lower doses of creatine over time (3 grams a day for 28 days) increased muscle creatine content, it is less clear whether low doses enhance exercise capacity. There are only a few well-controlled studies that reported that low dose creatine supplementation (5 to 6 grams a day of creatine for 10 to12 weeks) promoted greater gains in strength and muscle mass during training.
On the other hand, several other studies found no effect of low dose (2 to 3 grams/day) long-term creatine supplementation on exercise capacity. Consequently, it appears that the most effective way to increase creatine stores is to follow the creatine loading technique for at least 3 days followed by ingestion of 3 to 5 grams a day thereafter to maintain creatine stores.
4. Should athletes take creatine alone or with other nutrients?
Creatine uptake into the muscle has been reported to be sodium dependent and mediated by insulin. This means that taking creatine with large amounts of glucose (e.g., 80 to 100 grams) or carbohydrate/protein (e.g., 50 to 80 grams of carbohydrate with 30 to 50 grams of protein), which is known to increase blood insulin levels, may be an effective way to enhance creatine uptake. There is also evidence that coingesting creatine with D-pinitol may help creatine uptake into muscle.
Consequently, it is recommended that athletes take creatine with a high carbohydrate drink (e.g., juice or concentrated carbohydrate solution) or with a carbohydrate/protein supplement in order to increase insulin and promote creatine uptake.
5. When is the Best Time to Take Creatine?
Research shows that intense exercise increases anabolic hormone release. Ingesting carbohydrate and protein or essential amino acids following intense exercise may accelerate glycogen resynthesis as well as promote protein synthesis. Since insulin levels enhance creatine uptake, taking creatine after exercise with a carbohydrate and/or protein supplement may be an effective way to increase and/or maintain muscle creatine stores.
6. Should athletes cycle on and off creatine?
There is no evidence that cycling on and off creatine is more or less effective than loading and maintaining creatine. However, the greatest benefits of creatine supplementation occur with enhanced training. Therefore, if an athlete wants to cycle creatine, it's more effective to take creatine when they are involved in heavy training.
7. Does caffeine or acidity affect creatine?
Many of the initial studies on creatine mixed creatine in hot coffee or tea to help dissolve the creatine. These studies indicated that caffeine did not affect muscle uptake of creatine.
Some have also warned that mixing creatine in acidic solutions (e.g., juices) may break creatine down to creatinine. Yet, the acid level (pH) of coffee (about 4.5), grape juice (about 3), and orange juice (about 2.80) is less acidic than gastrointestinal secretions (about 1) and the acid in the stomach (about 1.5). We know that creatine is not broken down through the normal digestive process.
A number of creatine studies instructed the subjects to mix creatine with juice and reported muscle growth. Therefore, it is unlikely that mixing creatine in fruit juice would degrade creatine unless you let it sit for several days.
8. Do men and women respond differently to creatine supplementation?
About a third of the studies on creatine have evaluated women and/or mixed groups of men and women. Several initial short-term studies conducted on female athletes revealed limited enhancement of physical performance. This led some researchers to question whether women respond to creatine differently than men. However, a number of recent well-controlled short- and long-term studies in women have reported benefits.
In our research, we have found that women typically benefit from creatine during short-term supplementation. However, gains in body mass and fat free mass generally are not as rapid as men. Nevertheless, women do gain strength and muscle mass over time during training.
9. Weight gain derived from creatine ingestion: Is it water or muscle?
Creatine supplementation typically promotes gains in body mass and/or fat free mass. Some have suggested that because the gains are fairly rapid, that the gains must be fluid retention. The initial weight gain may promote some water retention, but a number of recent studies do not support this concept.
Most studies that have evaluated the effects of creatine supplementation on fluid retention and body composition indicate that although total body water increases, the increase appears to be proportional to the weight gained. Muscle is about 73% water. Therefore, if someone gained 10 pounds of muscle, 7.3 pounds of the weight gain would be water.
Numerous studies report that long-term creatine increases fat free mass without an increase in the percent of total body water. Additionally, several studies have found that these gains were accompanied by increased muscle fiber diameter (hypertrophy) and gains in strength. Consequently, the weight gain associated with long-term creatine supplementation appears to be muscle mass.
10. Should children or teenagers take creatine?
No study has indicated that creatine supplementation may be harmful for children or adolescent athletes. In fact, long-term creatine supplementation (e.g., 4 to 8 grams a day for up to 3 years) has been used as therapy for a number of deficiencies and neuromuscular disorders in children. However, it should be noted that much less is known about the effects of creatine supplementation in younger individuals.
Adolescent athletes should only consider taking creatine if the following conditions hold true:
1. The athlete is past puberty and is involved in serious/competitive training that may benefit from creatine supplementation;
2. The athlete is eating a well-balanced, performance-enhancing diet;
3. The athlete and his/her parents understand the potential benefits and side effects of creatine supplementation;
4. The athlete’s parents approve that their child takes creatine;
5. That creatine supplementation can be supervised by the athletes parents, trainers, coaches, and/or physician;
6. That quality supplements are used; and,
7. The athlete does not exceed recommended dosages.
If these conditions are met, then I personally do not see a reason why high school athletes should not be able to take creatine. Doing so may actually provide a safe nutritional alternative to anabolic steroids or other potentially dangerous supplements or drugs.
If these conditions are not met, then I do not believe that creatine supplementation would be appropriate unless prescribed by their physician. To me, this is no different than teaching young athletes’ proper training and dietary strategies to optimize performance.
Creatine is not a panacea or short cut to athletic success. It can, however, offer some benefits to optimize training of athletes involved in intense exercise in a similar manner that ingesting a high carbohydrate diet, sports drinks, and/or carbohydrate loading can optimize performance of an endurance athlete.
11. Is long-term creatine supplementation safe?
Athletes have been using creatine as a nutritional supplement since the mid 1960’s. Widespread use as a dietary supplement began in the early 1990’s. So far, no long-term side effects have been observed in athletes (up to 5 years), infants with creatine synthesis deficiency (up to 3 years), or in patient populations (up to 5 years).
One group of patients taking 1.5 to 3 grams a day of creatine has been monitored since 1981 with no significant side effects. All evidence suggests that creatine supplementation is safe when taken within recommended guidelines.
12. Is creatine supplementation ethical?
Several athletic organizations and special interest groups have questioned whether it is ethical for athletes to take creatine to enhance performance. Their rationale is that since studies indicate that creatine can improve performance and it would be difficult to ingest enough food to creatine load, that it is unethical to do so.
Others argue that if you allow athletes to take creatine, they may be more likely to try other dangerous supplements and/or drugs. Still others have attempted to lump creatine in with anabolic steroids and/or banned stimulants and have called for a ban on the use of creatine among athletes. Finally, fresh off of the ban of dietary supplements containing ephedra, some have called for a ban on the sale of creatine citing safety concerns.
Creatine supplementation is not currently banned by any athletic organization although the NCAA does not allow institutions to provide creatine or other "muscle building" supplements to their athletes (e.g., protein, amino acids, HMB, etc).
Moreover, although some countries limit how much creatine can be provided per serving in nutritional supplements, I am not aware of any country that has banned the sale of creatine. The International Olympic Committee considered these arguments and ruled that since creatine is readily found in meat and fish, there was no need to ban creatine.
Frankly, I don’t see creatine loading any different than carbohydrate loading. Many athletes ingest high calorie concentrated carbohydrate drinks in an effort to increase muscle glycogen stores and/or supplement their diet. If carbohydrate loading is not a banned practice, then creatine loading should not be banned.
The Facts About Creatine
Everything you need to know about creatine. Is it safe? Are there side effects? Just what is creatine, anyway? Men's Health has the answers
Jamie Bellavance
Richard Kreider, Ph.D., chairman of the Department of Health, Human Performance and Recreation and Director of the Exercise and Sport Nutrition Laboratory and Center for Exercise, Nutrition & Preventive Health Research at Baylor University, answers your most common questions about creatine supplementation.
Dr. Kreider has published more than 300& sport nutrition articles and abstracts that are published in scientific journals. He is also a Fellow of the American College of Sports Medicine, Fellow of the International Society of Sport Nutrition, and editor-in-chief of the Journal of the International Society of Sport Nutrition.
1. Are there any side effects to creatine?
The only significant side effect that has been consistently reported in scientific and medical literature has been weight gain. However, there have been a number of reported side effects such as stomach problems, muscle cramping, dehydration, and increased risk of muscle strains/pulls. There has also been concern that short and/or long-term creatine supplementation may increase renal (kidney) stress.
One research group suggested that creatine supplementation may increase an individuals risk to developing anterior compartment syndrome (ACS). Over the last few years a number of studies have indicated that creatine is not associated with any of these reported problems nor increase the likelihood of development of ACS. In fact, there is recent evidence that creatine may lessen heat stress and reduce the susceptibility to musculoskeletal injuries among training athletes.
While people who take creatine may experience some of these problems, incidences in creatine users aren't greater than subjects who take placebos and in some cases are less.
2. What is the best form of creatine to take?
Nearly all studies on creatine supplementation have evaluated pharmacological grade creatine monohydrate in powder form or have used oral or intravenous phosphocreatine formulations (a more expensive form of creatine).
Since creatine has become a popular supplement, there are a number of different forms of creatine that have been marketed (e.g., creatine candy/bars, liquid creatine, creatine gum, creatine citrate, effervescent creatine, etc). Many of these forms of creatine claim to be better than creatine monohydrate. However, no data indicates that any of these forms of creatine increases creatine uptake to the muscle better than creatine monohydrate.
The only potential benefits of these different forms of creatine are convenience, supplement variety, and/or taste preferences. The greatest disadvantage, however, is that many of these supplements are more expensive than creatine monohydrate. There is absolutely no evidence that you can take less of these types of supplements (e.g., liquid creatine or effervescent creatine) and get the same benefits than ingesting higher amounts of creatine monohydrate because of less breakdown in the stomach, greater intestinal absorption, faster absorption in the blood, and/or greater muscle uptake.
The best raw sources of creatine monohydrate are from Germany (e.g., Degussa’s CreaPure™) or the U.S. (e.g., Ferro Pfansteihl). Care should be taken to only purchase high quality creatine monohydrate that is produced in inspected facilities that adhere to FDA good manufacturing practice guidelines.
Editor's Note: We found another Creighton University study that found that creatine phosphate (Mega Creatine at gnc.com) improved performance three times as well as creatine monohydrate. The reason: Extra phosphate helps delay the onset of fatigue, says Joan Eckerson, Ph.D., C.S.C.S., the study's lead author.
3. Should athletes load or not load?
Research has shown that the most rapid way to increase muscle creatine stores is to follow the loading method, by taking 0.3 grams/kg/day of creatine monohydrate for 5 to 7 days (e.g., 5 grams taken four times per day). Studies show that this rate can increase muscle creatine. Once muscle creatine stores are saturated, studies indicate that you only need to take 3 to 5 grams of creatine monohydrate per day in order to maintain elevated creatine stores.
Most of the creatine is taken up by muscle during the first 2 to 3 days of the loading period. While there is one study that suggests that taking lower doses of creatine over time (3 grams a day for 28 days) increased muscle creatine content, it is less clear whether low doses enhance exercise capacity. There are only a few well-controlled studies that reported that low dose creatine supplementation (5 to 6 grams a day of creatine for 10 to12 weeks) promoted greater gains in strength and muscle mass during training.
On the other hand, several other studies found no effect of low dose (2 to 3 grams/day) long-term creatine supplementation on exercise capacity. Consequently, it appears that the most effective way to increase creatine stores is to follow the creatine loading technique for at least 3 days followed by ingestion of 3 to 5 grams a day thereafter to maintain creatine stores.
4. Should athletes take creatine alone or with other nutrients?
Creatine uptake into the muscle has been reported to be sodium dependent and mediated by insulin. This means that taking creatine with large amounts of glucose (e.g., 80 to 100 grams) or carbohydrate/protein (e.g., 50 to 80 grams of carbohydrate with 30 to 50 grams of protein), which is known to increase blood insulin levels, may be an effective way to enhance creatine uptake. There is also evidence that coingesting creatine with D-pinitol may help creatine uptake into muscle.
Consequently, it is recommended that athletes take creatine with a high carbohydrate drink (e.g., juice or concentrated carbohydrate solution) or with a carbohydrate/protein supplement in order to increase insulin and promote creatine uptake.
5. When is the Best Time to Take Creatine?
Research shows that intense exercise increases anabolic hormone release. Ingesting carbohydrate and protein or essential amino acids following intense exercise may accelerate glycogen resynthesis as well as promote protein synthesis. Since insulin levels enhance creatine uptake, taking creatine after exercise with a carbohydrate and/or protein supplement may be an effective way to increase and/or maintain muscle creatine stores.
6. Should athletes cycle on and off creatine?
There is no evidence that cycling on and off creatine is more or less effective than loading and maintaining creatine. However, the greatest benefits of creatine supplementation occur with enhanced training. Therefore, if an athlete wants to cycle creatine, it's more effective to take creatine when they are involved in heavy training.
7. Does caffeine or acidity affect creatine?
Many of the initial studies on creatine mixed creatine in hot coffee or tea to help dissolve the creatine. These studies indicated that caffeine did not affect muscle uptake of creatine.
Some have also warned that mixing creatine in acidic solutions (e.g., juices) may break creatine down to creatinine. Yet, the acid level (pH) of coffee (about 4.5), grape juice (about 3), and orange juice (about 2.80) is less acidic than gastrointestinal secretions (about 1) and the acid in the stomach (about 1.5). We know that creatine is not broken down through the normal digestive process.
A number of creatine studies instructed the subjects to mix creatine with juice and reported muscle growth. Therefore, it is unlikely that mixing creatine in fruit juice would degrade creatine unless you let it sit for several days.
8. Do men and women respond differently to creatine supplementation?
About a third of the studies on creatine have evaluated women and/or mixed groups of men and women. Several initial short-term studies conducted on female athletes revealed limited enhancement of physical performance. This led some researchers to question whether women respond to creatine differently than men. However, a number of recent well-controlled short- and long-term studies in women have reported benefits.
In our research, we have found that women typically benefit from creatine during short-term supplementation. However, gains in body mass and fat free mass generally are not as rapid as men. Nevertheless, women do gain strength and muscle mass over time during training.
9. Weight gain derived from creatine ingestion: Is it water or muscle?
Creatine supplementation typically promotes gains in body mass and/or fat free mass. Some have suggested that because the gains are fairly rapid, that the gains must be fluid retention. The initial weight gain may promote some water retention, but a number of recent studies do not support this concept.
Most studies that have evaluated the effects of creatine supplementation on fluid retention and body composition indicate that although total body water increases, the increase appears to be proportional to the weight gained. Muscle is about 73% water. Therefore, if someone gained 10 pounds of muscle, 7.3 pounds of the weight gain would be water.
Numerous studies report that long-term creatine increases fat free mass without an increase in the percent of total body water. Additionally, several studies have found that these gains were accompanied by increased muscle fiber diameter (hypertrophy) and gains in strength. Consequently, the weight gain associated with long-term creatine supplementation appears to be muscle mass.
10. Should children or teenagers take creatine?
No study has indicated that creatine supplementation may be harmful for children or adolescent athletes. In fact, long-term creatine supplementation (e.g., 4 to 8 grams a day for up to 3 years) has been used as therapy for a number of deficiencies and neuromuscular disorders in children. However, it should be noted that much less is known about the effects of creatine supplementation in younger individuals.
Adolescent athletes should only consider taking creatine if the following conditions hold true:
1. The athlete is past puberty and is involved in serious/competitive training that may benefit from creatine supplementation;
2. The athlete is eating a well-balanced, performance-enhancing diet;
3. The athlete and his/her parents understand the potential benefits and side effects of creatine supplementation;
4. The athlete’s parents approve that their child takes creatine;
5. That creatine supplementation can be supervised by the athletes parents, trainers, coaches, and/or physician;
6. That quality supplements are used; and,
7. The athlete does not exceed recommended dosages.
If these conditions are met, then I personally do not see a reason why high school athletes should not be able to take creatine. Doing so may actually provide a safe nutritional alternative to anabolic steroids or other potentially dangerous supplements or drugs.
If these conditions are not met, then I do not believe that creatine supplementation would be appropriate unless prescribed by their physician. To me, this is no different than teaching young athletes’ proper training and dietary strategies to optimize performance.
Creatine is not a panacea or short cut to athletic success. It can, however, offer some benefits to optimize training of athletes involved in intense exercise in a similar manner that ingesting a high carbohydrate diet, sports drinks, and/or carbohydrate loading can optimize performance of an endurance athlete.
11. Is long-term creatine supplementation safe?
Athletes have been using creatine as a nutritional supplement since the mid 1960’s. Widespread use as a dietary supplement began in the early 1990’s. So far, no long-term side effects have been observed in athletes (up to 5 years), infants with creatine synthesis deficiency (up to 3 years), or in patient populations (up to 5 years).
One group of patients taking 1.5 to 3 grams a day of creatine has been monitored since 1981 with no significant side effects. All evidence suggests that creatine supplementation is safe when taken within recommended guidelines.
12. Is creatine supplementation ethical?
Several athletic organizations and special interest groups have questioned whether it is ethical for athletes to take creatine to enhance performance. Their rationale is that since studies indicate that creatine can improve performance and it would be difficult to ingest enough food to creatine load, that it is unethical to do so.
Others argue that if you allow athletes to take creatine, they may be more likely to try other dangerous supplements and/or drugs. Still others have attempted to lump creatine in with anabolic steroids and/or banned stimulants and have called for a ban on the use of creatine among athletes. Finally, fresh off of the ban of dietary supplements containing ephedra, some have called for a ban on the sale of creatine citing safety concerns.
Creatine supplementation is not currently banned by any athletic organization although the NCAA does not allow institutions to provide creatine or other "muscle building" supplements to their athletes (e.g., protein, amino acids, HMB, etc).
Moreover, although some countries limit how much creatine can be provided per serving in nutritional supplements, I am not aware of any country that has banned the sale of creatine. The International Olympic Committee considered these arguments and ruled that since creatine is readily found in meat and fish, there was no need to ban creatine.
Frankly, I don’t see creatine loading any different than carbohydrate loading. Many athletes ingest high calorie concentrated carbohydrate drinks in an effort to increase muscle glycogen stores and/or supplement their diet. If carbohydrate loading is not a banned practice, then creatine loading should not be banned.
