Washington, Aug 2 : A nutritional supplement popularly known for boosting athletic performance and muscle strength does not improve exercise outcomes in patients with chronic obstructive pulmonary disease (COPD), says a new study.
The randomized, placebo-controlled, double blind study provided the most powerful evidence to date that the effect of Creatine (Cr) supplementation was negligible at best among these patients.
"We have evidence to suggest Cr uptake into muscles [in COPD patients] but are unable to explain why an increase in muscle Cr did not enhance training," wrote the study's lead author, Sarah Deacon, M.D., specialist registrar at the Institute for Lung Health at Glenfield Hospital in Leicester, England.
The results were published in the first issue for August of the American Journal of Respiratory and Critical Care Medicine by the American Thoracic Society (ATS).
Cr supplementation has been shown to improve short-burst, high-intensity exercise function in athletes, as well as enhancing isometric muscle strength, lower body endurance and lean body mass in the elderly.
To determine whether Cr supplementation could similarly enhance the physical condition of COPD patients, Dr. Deacon and co-researchers recruited 100 patients with COPD to either receive Cr or a placebo over the course of a seven week pulmonary rehabilitation program.
Those who were randomized to the placebo group were give lactose supplements that appeared identical to the Cr-containing supplements. Following a five-day loading period each subject followed maintenance dosing of 3.76 or 4 g of Cr or lactose respectively.
Of the original 100 subjects, 80 successfully completed the study. In both control and Cr groups, there were statistically significant improvements in functional and muscular performance during the loading phase, but no differences were seen between the groups.
The Cr group also showed a greater, but non-significant percentage of improvement in the incremental shuttle walking test with loading and after pulmonary rehabilitation, but additional analysis still showed no overall effect between it and the placebo group.
"The most likely explanation is that any benefits of creatine have been submerged by the large training effect of physical training alone," wrote Dr. Deacon.
This study, therefore, further validates that there is no substitute for the old-fashioned hard work that is an essential element of pulmonary rehabilitation.