Grip strength in the dominant hand and fat-free body mass (made mostly of muscle) increased when children with Duchenne muscular dystrophy (DMD)
took the dietary supplement creatine at a dose of 0.1 grams per kilogram of body weight per day for four months.
MDA grantee Mark Tarnopolsky, associate professor of pediatrics and medicine at McMaster University in Hamilton, Ontario, Canada, directed the study, in which 30 boys whose average age was 10 years participated.
Fifteen of the trial participants were given creatine for four months, followed by at least six weeks without treatment, and were then switched to a placebo (inactive substance). The other 15 started in a placebo group and were switched to creatine. The researchers and participants were not aware of which group was getting creatine until after the study was completed.
Pulmonary function, activities of daily living, and the ability to perform functional tasks such as climbing stairs or cutting a piece of paper with scissors didn’t show improvement, but a biochemical marker of bone degeneration was reduced.
“This study was only four months long, so perhaps longer studies are needed to see if creatine has an effect on the functional variables,” Tarnopolsky said.
Other studies of creatine in various neuromuscular disorders have shown mixed results, although few have used a placebo group for comparison, and many have included people with several different diseases, making it hard to draw conclusions about any particular disorder.
A 2003 Belgian study of creatine versus a placebo in 15 boys with Duchenne or the closely related disorder Becker muscular dystrophy found that the creatine group had less joint stiffness, better strength on one measure, better resistance to fatigue and, in those still walking, improved bone density.
Tarnopolsky noted that his present study confirms and strengthens the findings of previous studies that have been carefully conducted. “In addition, the evidence from basic science and animal studies are also supportive of a beneficial effect for creatine,” he said.
Earlier this year, Tarnopolsky’s group showed that the supplement was not helpful in type 1 myotonic dystrophy. “Tests showed that muscle from patients with myotonic dystrophy did not take up creatine and this was the likely reason for the lack of efficacy” he said.
MDA is a voluntary health agency working to defeat more than 40 neuromuscular diseases through programs of worldwide research, comprehensive services, and far-reaching professional and public health education.