UF Researcher Unlocks Secrets Of Popular Supplement Creatine

Source: Mike Powers -- (352) 392-0584; mpowers@hhp.ufl.edu

GAINESVILLE, Fla. --- A new study by a University of Florida professor finally helps explain some of the side effects associated with the popular muscle enhancer creatine.

Muscle cramping, heat illness and even kidney problems have long been rumored to be associated with taking the supplement, but previous studies couldn't explain these problems.

Now, in a study funded by one of the largest grants ever awarded by the National Athletic Trainers Association Research and Education Foundation, Michael Powers, an assistant professor in UF's department of exercise and sport sciences, shows for the first time that creatine increases both the body's overall water content and its ratio between intracellular and extracellular water.

The finding is important because it explains how the body's natural balance is thrown off by creatine consumption.

"As you work out, you're losing water from the extracellular space," Powers said. "If you already have a higher level of water in the intracellular space because of the creatine, you end up with even more of an imbalance. Over time it may make you dehydrate faster, which is associated with heat illness and cramping."

More importantly, however, overuse of the supplement can lead to kidney problems.

"The only place for the creatine to go is through the kidneys," Powers said. "After awhile, you retain water and your urine becomes highly concentrated. To avoid this problem, increase your fluid intake so that you'll have more of it to go through your kidneys and eliminate waste."

Creatine is a nonsteroidal, nonprescription muscle-enhancer taken orally prior to working out. Some users believe it gives them a training edge by helping increase body weight and muscle energy. According to a recent study, 25 percent of Major League baseball players and 50 percent of NFL players use the supplement.

"Creatine is the most popular supplement there's ever been," Powers said. "Anytime you have a supplement that is used to enhance your performance, it's going to be controversial. People want to know if it actually improves your performance, what it does to your body and if it's safe."

In a study completed as part of his dissertation at the University of Virginia and defended in December, Powers gave creatine supplements to 16 subjects and placebo supplements to another 16. During a five-week period, Powers took muscle samples and readings of cellular water content from the subjects.

The average weight gain in the first week for the creatine users -- which wasaccompanied by a significant increase in muscle creatine level -- was approximately three pounds, although one study participant gained 11 pounds. The subjects' percentage of body weight from water rose from 55 percent to 57 percent, and the percentage of water inside the cells rose from 58 percent to 60 percent. Although these numbers don't sound significant, Powers said, they are large enough changes to alter the body's natural balance.

Powers also stressed the importance of taking creatine in proper dosages. Much of the literature about creatine recommends a four- to five-day "loading" phase in which users take 20 to 25 grams of the supplement a day to increase creatine levels in their muscles. After that, users should take just five grams a day for the next few weeks and then give their bodies a week or two off to make sure they still are able to produce creatine naturally. However, Powers said many people ignore these instructions and assume that if they take more of the supplement, they'll bulk up more quickly.

Instead, Powers said, higher doses of creatine will be wasted, because the body can't absorb it in high amounts over time.

Studies such as Powers' are important in understanding creatine better, said John Oliver, the director of the NATA Research and Education Foundation, the organization that funded Powers' research.

"We're encouraging and funding studies that can bring us to a conclusion," Oliver said. "We recognize that people use creatine -- maybe to excess -- but we don't know what excess is yet."