Sports Ingredients: Creatine Update

In Nutritional Outlook’sNovember/December 2009 sports story, we covered creatine-in the form of creatine monohydrate-as an ingredient that could have healthful benefits beyond just athletics. A year later, it’s time to revisit creatine as an aid for sports.

In a study published in the July issue of the Journal of Strength and Conditioning Research, researchers at the University of Oklahoma assigned 50 men and women to anaerobic exercise tests while supplementing with creatine citrate (Cr) or placebo. Compared to creatine monohydrate (the source of creatine in most consumer supplements), creatine citrate is a less potent form that is more easily mixed in water.

In the randomized, double-blind, placebo-controlled trial, subjects were assigned to take 20 packets of Cr (one packet containing 5 g of Cr and 18 g of dextrose) or placebo (18 g of dextrose) over five days, before testing. Following this loading phase, two days of running on a treadmill showed that Cr did not affect body weight in men or women, but it did improve the anaerobic running capacity in men by 23%. The researchers concluded that creatine citrate “may be used before competition by athletes to provide improvements in high-intensity, short-duration activities.”

In another study, published in June in the journal Nutrition, 20 men and women (average age of 21) were assigned to exercise while supplementing with creatine based on personal body weight (average of 2.3 g daily) or placebo, for six weeks. Subjects were asked to perform five sets of 30 knee extensions.

During sets two, three, four, and five, resistance to fatigue was significantly higher for the creatine group (7, 9, 9, and 11% higher, respectively). Such results fall in line with the continuing theory that creatine is supportive of short-term, high-intensity workouts.

As for long-term endurance workouts, studies continue to show creatine may have little to no effect here. A study published in July by the Journal of the International Society of Sports Nutrition found that creatine monohydrate had no significant effect on endurance in cyclists performing in a simulated two-hour race (on cycle ergometers). Twelve male cyclists performed the race before and after 28 days of 3-g creatine monohydrate supplementation or placebo. The difference in completion times between each group was not statistically significant.