Creatine, a popular nutritional supplement used by weightlifters and sprinters to improve athletic performance, could lend muscle strength to people with muscular dystrophies. Muscle strength increased by an average of 8.5% among patients taking creatine, compared with those who did not use the supplement, according to a recent review of studies. Creatine users also gained an average of 1.4 pounds more lean body mass than nonusers.
The evidence from the studies “shows that short and medium-term creatine treatment improves muscle strength in people with muscular dystrophies and is well-tolerated,” said Rudolf Kley, MD of Ruhr University Bochum in Germany.
Creatine is found naturally in the body, where it helps supply energy to muscle cells. Athletes looking for short bursts of intense strength have used creatine in powders or pills for decades, but the supplement became more popular after the 1992 Barcelona Olympics, when sprinters, rowers and cyclists went public with their creatine regimens.
Although creatine has been widely studied as a performance enhancer, it is still not clear if the supplement makes a difference, according to Roger Fielding, PhD, of Tufts University, who also recently wrote a review of creatine treatments for neuromuscular diseases.
People with muscular dystrophies can have lower-than-normal levels of creatine, along with increasing muscle weakness as their disease progresses. Since some studies suggest that creatine improves muscle performance in healthy people, many researchers have reasoned that it might be helpful in treating muscle disease.
The researchers reviewed 12 studies that included 266 people with different types of muscular dystrophy. People in the studies who took creatine supplements used them for 3 weeks to 6 months.
In muscular dystrophies, the proteins that make up the muscles themselves are either missing or damaged. In a related group of disorders called metabolic myopathies, the chemicals that help muscles operate go awry. Although creatine seemed to help many patients with muscular dystrophies, those with metabolic myopathies gained no more muscle strength or lean body mass than patients who did not use the supplement.
The reason for the contrasting results — creatine’s “fairly consistent” effects in muscular dystrophy and lack of effectiveness in metabolic diseases — is “not entirely clear,” Kley said, calling for more research on treatment for metabolic disorders.
