LAS VEGAS – Pediatricians should not condemn all performance-enhancing drugs, according to Dr. Gregory L. Landry, a pediatrician who specializes in sports medicine at the University of Wisconsin, Madison.
Because the use of creatine has been associated with little risk, physicians should take a more neutral attitude toward it than toward more dangerous substances such as anabolic steroids, he said. He acknowledged that this position contradicts the American Academy of Pediatrics position (Pediatrics 2005;115:1103-6), which states that the "use of performance-enhancing substances for athletic or other purposes should be strongly discouraged."
"I disagree with the academy," Dr. Landry said at a pediatric update sponsored by the American Academy of Pediatrics California Chapter 9. "Compared to other risk-taking behaviors, creatine is low risk. We have more important battles [to fight], like seat belts, binge drinking, and unprotected sex."
Doctors should be honest with their patients about potential benefits as well as risks to various performance-enhancing substances, he said. Although there is evidence that creatine, caffeine, carbohydrate-electrolyte beverages, and sodium bicarbonate may work, amino acids, beta-hydroxy-beta-methylbutyrate, and chromium are not helpful, and anabolic steroids should be avoided because of their side effects, he said.
The use of creatine appears to be increasing. "Where I work, this is the most popular supplement that kids are asking about," he said. In one survey of 4,011 Wisconsin high school athletes, more than a quarter of the boys had used creatine supplements.
Exogenous creatine occurs naturally in foods such as red meat and fish, and human beings can synthesize it as well, so there is no daily requirement. But exogenous creatine is absorbed 100% unchanged.
In muscles, it is converted to phosphocreatine, which in turn produces adenosine triphosphate, a molecule that provides energy. With maximum exertion, levels of this molecule fall. Creatine may also buffer lactate. "Many athletes feel they can work harder and longer by using creatine," said Dr. Landry.
Several studies have investigated the effects on athletic performance, he said. In general, they suggest that creatine supplementation can increase peak power, but that it may be detrimental in endurance sports. "The best benefit is in repeated short bursts of power, such as in U.S. football and sprinting," said Dr. Landry.
Common short-term side effects include nausea, abdominal pain, diarrhea, water weight gain, and possible muscle strains. Dr. Landry said he encourages athletes to drink more water when they are taking creatine. But a meta-analysis found no evidence that the supplements increase heat illness (J. Athl. Train. 2009;44:215-23). One case of renal failure in an athlete taking creatine was reversed when the athlete stopped taking the supplements.
The supplements are readily available for sale. Uptake in muscles is enhanced by ingesting them with 90 g of glucose, said Dr. Landry.
Creatine is not banned by any sports-governing body, nor are any testing for it. However, Dr. Landry cautioned that commercially available supplements are often tainted, so he advised purchasing them from a scientific source.
Moving quickly through a list of other supplements Dr. Landry said there is evidence that caffeine, which increases the utilization of fat, may have benefits in endurance sports like cycling and rowing. Side effects include anxiety, diuresis, diarrhea, and palpitations. The National Collegiate Athletic Association has set a limit on the amount of caffeine allowed in athletes’ urine, but other sports-governing bodies have not.
Sodium bicarbonate may help in medium-duration sports, such as a 1,500-m race. However, it can cause bloating and diarrhea.
Numerous studies show that athletes drinking carbohydrate-electrolyte beverages performed better in endurance events, although not in short events. Dr. Landry recommended a carbohydrate concentration of 5%-7%.
Pharmacologic androgens do build muscle and enhance performance, but are associated with many side effects. Androgenic supplements are less effective and may have more side effects. Androgen precursors are of dubious benefit, he said.
Beta-hydroxy-beta-methylbutyrate might increase muscle mass, but has not been shown to have a benefit in athletic performance. No short-term side effects have been shown.
Amino acids probably don’t help American athletes because most athletes are already getting more than enough in their diets.
Chromium could theoretically increase muscle mass, but benefits for athletic performance have not been shown, and cases of liver failure and renal dysfunction have been reported.
As for what advice Dr. Landry gives his own patients, "I usually talk about diet," he said. "What we do with our college athletes is we’re teaching them to cook and we’re teaching them to shop. We tell them that’s going to have a bigger effect on their performance than any supplement."