ZackMurphy

(originally written for ISSA-SPN certification, (c) Zack Murphy, 2005)

Topic: Creatine and Strength Performance

What is Creatine?
Creatine has gained increasing attention over the past few years as a top-selling and highly-touted sports supplement. A naturally occurring substance, creatine plays an important role in the production of energy in the body. Simply, the body converts supplemental creatine to phosphocreatine, a form of stored energy used by muscles.

Though anabolic steroids are in a completely different category than the various over-the-counter supplements like creatine, the allure and promise of enhanced strength and performance is identical. But does creatine work? Is it worth the hype, are there risks, and what should those seeking to take creatine consider prior to taking their first dose?

What Do We Know About Creatine?
The evidence for creatine is vast. Though not truly definitive, of all sports supplements, creatine probably has the most evidence behind it. Numerous, varied studies suggest it can increase athletic performance in sports, particularly those that involve intense, short bursts of activity.

The basic premise behind creatine use is that supplemental creatine can build up a reserve of phosphocreatine in the muscles, to help them perform on demand. Supplemental creatine may also assist the body in making new phosphocreatine faster when it has been used up by intense activity.

Although trace amounts of creatine may exist in the daily diet of most athletes, it is not an essential nutrient because your body can make it from certain amino acids. Provided you eat enough protein (the source of these amino acids), your body will make all the creatine you need for good health.

Meats such as chicken and fish are the most significant dietary source of creatine and its amino acid building blocks. For this reason, vegetarian athletes may potentially benefit more from creatine supplementation. That said, though creatine is found in food, it is not necessary to seek dietary sources of whole creatine when adequate source proteins are present.

How Would One Supplement Creatine?
Dosing suggestions for supplemental creatine varies tremendously depending on the goal of the athlete and the form of the creatine being used. In general though, for muscular and exercise enhancement, a typical creatine regimen begins with a "loading phase" of 15 to 30 grams daily (divided into 2 or 3 separate doses) for 3 to 4 days. This “creatine load” is then followed by a “maintenance phase” of 2 to 5 grams daily. By comparison, we typically get only about 1 gram of creatine in the daily diet from natural, non-supplemental sources.

Some fitness and sport medicine professionals recommend skipping the loading dose and jumping immediately to the maintenance phase. This recommendation tends to be made out of concerns over safety, though such concerns have little merit.

Creatine's ability to enter muscle cells can be enhanced by ingesting it with glucose, fructose, or other simple carbohydrates. In addition, prior use of creatine might enhance the sports benefits of carbohydrate-loading.

Conversely, caffeine may block the effects of creatine. As caffeine is sometimes used by bodybuilders and fitness enthusiasts to additionally benefit fat loss, this should be considered when dosing creatine (and elimination of caffeine from the diet would be the most responsible first step).

But Does Creatine Really Work?
Over the past 10 years, supplemental creatine has become one of the best-selling and best-documented products for enhancement of athletic performance. The best evidence we have of creatine’s effectiveness points to benefits in forms of exercise that require repeated short-term bursts of high-intensity exercise.

Several small double-blind studies suggest that creatine can improve performance in exercises that involve repeated short bursts of high-intensity activity. Most team sports, such as basketball, baseball, football, or soccer, as well as individual events, such as some track events and resistance exercises like weightlifting, and powerlifting, could see an athlete’s performance improve with proper creatine supplementation.

For example, a double-blind study investigated creatine and swimming performance in 18 men and 14 women. Men taking the supplement had significant increases in speed when doing 6 bouts of 50-meter swims started at 3-minute intervals, as compared with men taking placebo. However, their speed did not improve when swimming 10 sets of 25-yard lengths started at 1-minute intervals. It may be that the shorter rest time between laps was not enough for the swimmers' bodies to resynthesize phosphocreatine.

Interestingly, none of the women enrolled in the study showed any improvement with the creatine supplement. The authors of this study noted that women normally have more creatine in their muscle tissue than men do, so perhaps creatine supplementation (at least at this level) is not of benefit to women, as it appears to be for men. Further research is needed to fully understand this gender difference in response to creatine.

In another double-blind study, 16 physical education students exercised 10 times for 6 seconds on a stationary cycle, alternating with a 30-second rest period. The results showed that individuals who took 20 g of creatine for 6 days were better able to maintain cycle speed. Similar results were seen in many other studies of repeated high-intensity exercise, although there have been negative results as well.

Isometric exercise capacity (pushing against a fixed resistance) also may improve with creatine.

In addition, two double-blind, placebo-controlled studies, each lasting 28 days, provide some evidence that creatine and creatine plus HMB (beta hydroxymethyl butyrate) can increase lean muscle and bone mass. The first enrolled 52 college football players during off-season training, and the other followed 40 athletes engaged in weight training.

What About Endurance Athletes or Other Uses?
Studies of endurance or nonrepeated exercise, however, have not shown benefits. Therefore, creatine probably won't help you for marathon running or single sprints.

Creatine has also been proposed as an aid to promote weight loss and to reduce the proportion of fat to muscle in the body, but the evidence to support this is largely epidemiological, and there is little direct evidence that it is effective for this purpose.

That said, because creatine can increase the lean body mass of an athlete, that athlete’s percentage of total bodyfat could be decreased, though not necessarily in total fat volume.

There is also evidence which suggests that creatine supplements may be able to reduce levels of triglycerides in the blood. Creatine supplements might also help counter the loss of muscle strength that occurs when a limb is immobilized, such as following injury.

Preliminary studies, including small double-blind trials, suggest that creatine may be helpful for reducing fatigue and increasing strength in various illnesses where muscle weakness occurs, including congestive heart failure, Huntington's disease, McArdle's disease, mitochondrial illnesses, myotonic dystrophy, and muscular dystrophy.

Easy fatigability is one unpleasant symptom of congestive heart failure. Creatine supplementation has been tried as a treatment for this symptom, with some positive results.

A double-blind study examined 17 men with congestive heart failure who were given 20 g of creatine daily for 10 days. Exercise capacity and muscle strength increased in the creatine-treated group. Similarly, muscle endurance improved in a double-blind, placebo-controlled crossover study of 20 men with chronic heart failure. Treatment with 20 g of creatine for 5 days increased the amount of exercise they could complete before they reached exhaustion.

These results are promising, but further study is needed.

Are There Risks?
The primary criticism of creatine supplementation has been regarding its impact on the liver and kidneys. Creatine appears to be safe, at least in healthy athletes, although large, systematic, long-term safety studies have not been performed. No significant side effects have been found with the regimen of several days of a high dosage (15 to 30 g daily) followed by 6 weeks of a lower dosage (2 to 3 g daily). A placebo-controlled study of 100 football players found no adverse consequences during 10 months to 5 years of creatine supplementation. Creatine does not appear to adversely affect the body's ability to exercise under hot conditions.

However, because creatine is metabolized by the kidneys, fears have been expressed that creatine supplements could cause kidney injury, and there are two worrisome case reports. However, evidence suggests that creatine is safe for people whose kidneys are healthy to begin with, and who don't take excessive doses. Nonetheless, individuals with kidney disease, especially those on dialysis, should avoid creatine.

Another concern revolves around the fact that creatine is metabolized in the body to the toxic substance formaldehyde. However, it is not clear whether the amount of formaldehyde produced in this way will cause any harm. Three deaths have been reported in individuals taking creatine, but in each case, other causes were most likely responsible.

As with all supplements taken in very high doses, it is important to purchase a high-quality form of creatine, as contaminants present even in very low concentrations could conceivably build up and cause problems.

Where Do We Go From Here?
Athletes have increasingly turned to over-the-counter sports supplements in recent years to help push their abilities to a higher level. This eager supplementation and body modification has come to a new climax just in the past few weeks, with professional athletes and executives from the various sports testifying in front of congressional panels on the rumors and allegations of rampant steroid use.

Only additional clinical study will decide if creatine is here to stay, or if it will become simply the next product in the long line of “shooting stars” in the fitness supplement industry. As of this date, it appears that creatine is a viable option, likely to remain present in athletic performance and strength supplementation.

bigDman

very good and informative article good job

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