Research on Low-Dose Creatine?
Though creatine is one of the most well-researched ergogenic or performance-enhancing supplements available, a new study explored the effects of altering the dosing range to achieve different results. Specifically, a new study published in the journal, Nutrition,explored the effect of low dose creatine supplementation on body composition and muscle function (Rawson et al, 2010).
- 20 healthy men and women (21 +/- 2 y old) were randomized to receive either creatine (0.03 g . kg(-1) . d(-1) or placebo for 6 weeks in a double blind placebo-controlled study.
- Given that an average male weights about 72kg, this dose of creatine would typically approximate to 2.16 grams/day. This dose is much lower than a typical creatine loading or maintenance dose.
What did the subjects do for those six weeks? According to the study authors, they were instructed to maintain similar habitual dietary and physical behaviors during the study.
- No significant increases in body mass, lean body mass, fat mass, total body water, body fat percent, or maximal strength
- Plasma creatine increased significantly in the creatine supplementation group only (+182%, p=.03)
- The creatine supplementation group was more resistant to fatigue during sets 2 (7%), 3 (9%), 4 (9%), and 5 (11%) (all P < 0.05).
- The placebo group did not demonstrate an improvement in fatigue resistance in comparison.
Study author conclusions:
“CONCLUSION: Ingesting a low dose ( approximately 2.3 g/d) of creatine for 6 wk significantly increased plasma creatine concentration and enhanced resistance to fatigue during repeated bouts of high-intensity contractions.”
I once did a research study on methylphenidate which involved comparing the behaviour response to methylphenidate (Ritalin) among different subtypes of patients with Attention-deficit disorder. The study never did get published and my supervisor at the time joked that we should submit it to “the Journal of Negative Results.”
What did he mean? Well, basically there’s a bias against publishing studies that have negative findings. Why? There’s a potential that the negative result is not valid due to a Type II error. Type II errors occur when you fail to find a difference when there really is one due to poor sensitivity.
In this case, though the authors wrote that their hypothesis was:
“We hypothesized that very low-dose creatine ingestion, when ingested over a sufficient period, would improve muscle function.”
I am somewhat skeptical based on the data tables that they present. Though their data for group by time interaction didn’t reach the level of statistical significance for changes in body composition in either group, the placebo group actually demonstrated improvements in fat free mass, total body weight and reductions in fat mass and body fat % (not statistically significant). In contrast, their creatine group demonstrated nearly the opposite effect. The creatine intervention group demonstrated decreases in body mass, and total body weight, while increasing their body fat percentage and fat free mass (not statistically significant).
If I had to guess, the level of activity and diet was probably not well controlled based on those results. I would venture a guess that this “negative” data lead the study authors to their post-hoc analysis of the effect of low-dose creatine on muscle function.
In fact, the positive findings in this study (increased resistance to fatigue) were found in post-hoc analysis which means that these were not measures that they were specifically looking for prior to the onset of the study. This is sometimes referred to as the post-hoc data dredge and is a method used by researchers so that they don’t have to submit their study results to the Journal of Negative Results.
[box type="important"]Bottom line:
This poorly constructed study suggests that low-dose creatine supplementation might be effective for cranking out an extra rep or so if you consume creatine for six weeks. Would I bother with low-dose creatine? No, if I were going to use creatine, I would look at more effective dosing regimes.[/box]
Previous research on Creatine:
- When taken at dose of 20 g/day (divided in four doses of 5g each for 5 days), creatine has been shown to improve anaerobic performance in swimmers.
- Creatine taken at a dose of 9g/day along with 36g/day of protein and 6 g/day of conjugated lineoleic acid has been shown to increase strength and lean tissue mass in response to resistance training.
- A comparison of a combination of creatine/protein/carboydrate was more effective in promoting muscle hypertrophy than the protein/carbohydrate supplement alone.