Clarifying The Creatine Myth
Steven S. Plisk, M.S., C.S.C.S.
Richard B. Kreider, Ph.D., FACSM, MX
An article entitled “The Creatine Myth” was published in the April 2000 issue of Wrestling U.S.A. Magazine. This article was adapted from a guest editorial by Plisk originally appearing two years earlier in the NCAA News (22), but without the author’s input. We respect the need to paraphrase and condense this information, and most of what appears in “The Creatine Myth” is accurate. However, some statements were changed significantly enough to affect their meaning, and a few of these were quoted and criticized by Matt Brzycki in his rebuttal in the January & February 2001 issues. He has also challenged some of our research findings.
Matt didn’t address his comments to us before going public with them, compounding the problem. Had he done so, he would have known that he’s trying to discredit some statements that were never made. He has also presented some creative interpretations of the evidence, and raised some interesting questions in the process. We would like to address these issues, as they have significant implications for the wrestling community.
Creatine’s Effect On Performance
The original NCAA News editorial by Plisk states the following (22): “Athletes know that creatine is legal and readily available, and that it works. They have experienced or seen these results first-hand, and many are aware of the research demonstrating its effect on metabolic power, capacity and recoverability as well as muscle mass and strength.” In the abbreviated version in Wrestling U.S.A., “metabolic power, capacity and recoverability” was rephrased simply as “endurance”. Matt has taken issue with this because creatine has not been shown to enhance submaximal endurance performance. Actually, a review of the literature reveals that about half the studies looking at creatine’s effect on aerobic capacity report significant improvements (1,3-11,13-21,24-27,29-34). This is not surprising considering its role in the phosphocreatine circuit (a metabolic pathway that acts as the cell’s energy conduit and flux capacitor).
If Matt feels that either of us is unclear on this issue, we invite him to read the manuscript we co-authored in the February 1999 issue of Strength & Conditioning Journal (23) as well as the recent book by Williams, Kreider & Branch (32). To clarify, short-term creatine supplementation can improve:
· maximal strength and power [5-15%], and work performed during sets of maximal efforts [5-15%]
· single-effort sprint performance [1-5%], and work performed during repetitive sprints [5-15%]
The higher the intensity and/or briefer the recovery, the greater creatine’s effect on power and work output in single or repeated maximal efforts. Its effect is less pronounced when recovery is prolonged [=5 min]. Over the long term, creatine can also promote significantly greater gains in strength, sprint performance and lean mass during training than in matched-paired controls.
Matt has also taken issue with creatine’s documented effects on muscle mass and strength during training. Throughout his two-part article, he cites partial information from various studies to support his view that the literature is inconclusive. Since the authors’ names and publication volumes/issues are omitted, however, these resources can’t be identified. In any case, they represent a minority of the published research examining this topic.
Don’t take our word for it: Interested readers are encouraged to review the literature cited above for a balanced perspective. Some well-controlled studies have shown that there are non-responders to creatine supplementation. But the predominant trend is for creatine to improve certain parameters of strength, mass and/or sprint capacity. About two-thirds of the 350+ published studies on creatine’s effect on performance report statistically significant results; whereas those with non-significant results often report improvements of 1-10% that don’t meet the p<.05 probability level for various reasons (e.g., low subject number, measurement error in the performance tests used, and/or problems with experimental control).
Is creatine effective across the full spectrum of athletic activities? No. Is it for everyone? Probably not, as will be discussed below.
ACSM Consensus Statement
A notable event occurred in Indianapolis in April 1999. The American College of Sports Medicine conducted an official roundtable, and subsequently published a consensus document entitled “Physiological and Health Effects of Oral Creatine Supplementation” in the March 2000 issue of their official journal, Medicine & Science in Sports & Exercise (26). This document reviewed the literature published up to that point, and concluded that creatine can enhance:
· strength gains (in conjunction with body mass) in strength training programs
· exercise performance in brief, powerful activities, especially during repeated bouts
Matt refers to this document elsewhere in his article, in regard to the ACSM’s cautionary remarks about unknown potential effects of high-dose supplementation, and limited data on long-term benefits and risks. However, he ignores their conclusion regarding creatine’s effect on strength gain during training; as well as the fact that its use hasn’t been linked to gastrointestinal, renal and/or muscle cramping complications (also discussed below). The ACSM is a conservative organization in terms of what it states in its official documents, and it’s safe to say that the committee overseeing this project would not have drawn these conclusions about creatine’s training effects if the evidence were inconclusive.
The ACSM’s conservative view is also evident in the way the committee follows each conclusion about creatine’s effectiveness and safety with cautionary paragraphs that aren’t supported by the data. Furthermore, many of their concerns have been examined in detail since this report was published. These studies indicate that creatine supplementation does not adversely affect heat tolerance, hydration, renal function, or muscle injuries in healthy subjects during training (1,3,24,30,33,34).
The Laboratory vs. The Real World?
At the conclusion of the first part of his article, Matt makes the following comment: “Collectively, this ‘solid research’ shows that any improved performance that may occur in laboratory settings does not translate into improved performance in realistic situations.” Recent research has proven this criticism to be obsolete and shortsighted. For example, some new studies indicate performance improvements in repetitive swimming, repetitive running, and intermittent soccer. Once again, interested readers are encouraged to review the current literature (1,3,24,30,33,34).
In the second part of his article, Matt states that “creatine can increase body mass, not lean-body mass or lean-muscle mass. And the most likely reason for the increased body mass is primarily due to water retention (within skeletal muscle cells)….” In fact, creatine has been reported to stimulate myofibrillar protein synthesis (2,6,12,28), with its normal resting concentrations usually at the low end of the range needed to maximize this effect (possibly accounting for how the process can be augmented by elevated tissue creatine levels via supplementation). Furthermore, the cellular swelling (a.k.a. volumizing) effect resulting from creatine’s osmotic activity may partially explain the mechanism by which some hormones and amino acids regulate metabolic control — and in turn modulate anabolic activity — via hydration status (16,17,27). The changes in muscle mass observed during chronic creatine supplementation and training, and accompanying improvements in strength and power, argue against simple fluid retention.
Keep in mind that skeletal muscle is over 70% water. Thus, a 10 lb. gain in muscle tissue represents about 7 lbs. of fluid regardless of whether it’s augmented by creatine use. Matt failed to mention that the same studies reporting creatine’s effect on total body water also show that it doesn’t affect the body’s percentage of water — in other words, the weight gained is normal and proportional in terms of fluid content.
For these reasons, it is simplistic and irresponsible to attribute creatine-assisted gains in body weight to transient water retention. In the first place, such comments are misleading, and give rise to confusion about what creatine does or doesn’t do. More importantly, this particular comment opens the door for an I’ll-just-cut-more-weight mentality among athletes competing in body weight classes. This brings us to a key point.
Implications For Wrestlers
Here’s the take-home message:
· Wrestling may not fall within the range of brief/powerful/repetitive activities that creatine use can enhance.
· Wrestlers need to know how creatine use can affect body composition. Specifically, in addition to augmenting muscle mass during strength training, studies examining creatine’s effect on hydration have shown that it may make it more difficult to dehydrate — i.e. to cut weight.
There’s a very real issue in terms of whether creatine is an appropriate supplement to use in sports where you have to make weight. It has nothing to do with being inherently good or bad; it has to do with how it works, and with the nature of the sport. As pointed out by Plisk in the NCAA News: Wrestlers are a different breed of athlete who embody a gritty attitude and do-what-it-takes mind set better than perhaps anyone else. If athletes (or coaches) are led to believe that creatine use simply causes temporary water retention, they may think it’s just a matter of cutting a few additional pounds before competition with a little extra time and effort. If they don’t understand the documented creatine-hypertrophy link, they may be setting themselves up for serious health consequences. And so which is the real problem — creatine itself, or the misinformation about it?
Let’s do a reality check: First, there’s too much evidence documenting creatine’s effect on muscle mass to be dismissed as inconclusive. Second, the more extreme the weight-cutting methods, the greater the risk. With athletes’ health and safety at stake, we must be very careful to present clear, evidence-based information on this issue.
Other Health & Safety Issues
In the second part of his article, Matt makes some interesting observations that raise additional questions:
· He states that “the large fluid shift into skeletal muscle (intracellular water retention) that is caused by creatine supplementation is thought to dilute electrolytes, thereby increasing the potential for muscle cramps.” Thought by whom, based on what evidence? Studies evaluating the effects of creatine on electrolyte status have shown no effect, even during intense training in a hot environment.
· He proposes an intriguing theory of dehydration/heat-related illness in which “creatine could intensify an already dehydrated state, resulting in heightened thermal stress and a resultant life-threatening situation” via water retention, fluid shift into the muscle, and reduced plasma volume. We’re curious if Matt is part of a research group that is investigating this hypothesis, and what evidence he can provide? In fact, about 10 studies show that athletes who take creatine during intense training experience the same or a lower incidence of heat related problems and cramps than those not using creatine. Where is the evidence that creatine adversely effects heat tolerance, hydration status and/or cramping in athletes or other healthy subjects?
· He states that “it is speculated that the intracellular water retention related to the use of creatine increases the intramuscular pressure which could contribute to muscle strains and/or dysfunction.” Speculated by whom, based on what evidence? Once again, where are the studies showing that creatine promotes such problems in healthy subjects? Several show that athletes taking creatine during intense training have the same (or lower) incidence of muscle injuries than those not using creatine.
· He states that “creatine may cause a variety of gastrointestinal disturbances.” Perhaps so if the product is impure, or not produced according to industry standards for quality control and assurance (23,32). In fact, such reports in creatine studies are rare, and occur at a similar (or lower) rate than those associated with carbohydrate placebos. A corresponding amount of meat is thought to produce a few gastrointestinal disturbances too. And so wouldn’t it be more accurate to state the opposite?
The “what ifs” about creatine are getting all the press, and are being anecdotally “reported” in non-peer reviewed newspapers and magazines by unqualified journalists who aren’t held accountable for checking their facts. What isn’t being reported in the popular media is the volume of medical and scientific research that has been conducted; and documentation about the antitumor, antiviral, antidiabetic, and protective effects (e.g., from tissue hypoxia, ischemia, and neurodegenerative or muscle damage) of creatine and its analogs (1,3-11,13-21,24-27,29-34). Where is the evidence of side effects other than weight gain in healthy subjects?
Comparing Creatine & Carbohydrate Loading
Matt has criticized the statement that “it may be more appropriate to compare creatine supplementation with the practice of carbohydrate loading as a means of improving metabolic power and capacity than it is to compare it with ‘body-building’ supplements.” (22) Perhaps our understanding of the creatine kinase system, phosphocreatine circuit, and effect of supplementation on intramuscular creatine/phosphocreatine pools differs from his. Once again, if he feels that we have misinterpreted this issue, we invite him to read our discussion of it in Strength & Conditioning Journal (23) as well as the references cited there.
Citations & Qualifications
Finally, Matt does cite the authors’ names in one of the studies mentioned in his article: He tries to discredit a manuscript by Dr. Richard Kreider and colleagues in Medicine & Science in Sports & Exercise (18), where Steven Plisk participated as part of his research team (Matt repeatedly mentions this affiliation, three times in case you miss two of them).
Matt challenges this study on the grounds that the experimental group’s serum creatinine level and liver enzyme efflux are described as normal. Unfortunately he doesn’t provide references to support his belief that their values are abnormal; nor does he indicate what population he’s comparing our results with. Since he chose Wrestling U.S.A. as a forum to express his viewpoint, perhaps he would be courteous enough to share that information with its readers? (A hint: non-athletes have lower serum enzyme and creatinine levels than athletes — especially distance runners, whose values are typically higher than those we reported.) And since hydration status can also affect creatinine levels, maybe he could tie this in with his dehydration/heat illness theory?
Indeed, in light of Matt’s unique insights on creatine physiology and supplementation, perhaps he would also be so kind to share with us his extensive background in this area. Surely he has advanced degrees and accredited certifications in the subjects of applied physiology, clinical nutrition, or related disciplines. He has demonstrated his ability to synthesize and communicate evidence-based knowledge on this topic; and likewise to critique every aspect of the investigative process, from obtaining research grants to interpreting results. He must therefore be a skilled research scientist as well as practitioner, with ample first-hand experience publishing his findings in peer-reviewed journals, presenting them at symposia, and making other contributions to the scientific and coaching communities. Possibly he serves on the editorial board of one or more organizations’ professional journals as well, participating in the blind-review process of manuscripts submitted by other research groups. In any case, we would like clarification on Matt Brzycki’s qualifications as an expert on this subject.
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