Creatine may boost strength in muscular dystrophy sufferers
boost performance, may increase muscle strength in people with
muscular dystrophies by about nine per cent, says a new review.
The review, published in the Cochrane Database of Systematic Reviews, "shows that short- and medium-term creatine treatment improves muscle strength in people with muscular dystrophies and is well-tolerated," said lead reviewer Dr. Rudolf Kley of Ruhr University Bochum in Germany.
Muscular dystrophies refer to 30 or more genetic and hereditary muscle disease, where the proteins that make up the muscles are either missing or damaged. About a quarter of a million Americans and 200,000 Europeans are reported to live with the condition for which there is no cure.
People with muscular dystrophies are said to have lower-than-normal levels of creatine, and, since some studies have suggested that creatine enhances muscle performance in healthy people, some experts have suggested the amino acid may offer benefits against muscle diseases.
Creatine, which occurs naturally in foods like fish and red meat, is banned in some countries because of studies showing a possible link between long-term supplementation and increased cancer risk. It is not banned by the International Olympic Committee, which classifies it as food.
The amino acid creatine is available as a dietary supplement in liquid, tablet and powder forms, chiefly in the form of creatine monohydrate.
The new review looked at 12 studies involving 266 people with different types of muscular dystrophy. The period of creatine supplementation ranged from three weeks to six months.
Kley and his co-reviewers report that, amongst those taking creatine supplements, muscle strength increased by an average of 8.5 per cent, and gained an average of 0.6 kg (1.4 lbs) more lean body mass compared to those who did not use the supplement.
Despite the results being "fairly consistent" for creatine's apparent benefits, the researchers note that people with metabolic myopathies, another group of hereditary muscle diseases, gained no more muscle strength or lean body mass than patients who did not use the supplement.
The reason for the contrasting results is "not entirely clear," said Kley, and he called for more research on treatment for metabolic disorders.
The review was supported by the Neuromuscular Center Ruhrgebiet/ Kliniken Bergmannsheil, at Ruhr-University Bochum and the Hamilton Health Sciences Corporation, in Canada.
A risk assessment by John Hathcock and Andrew Shao from US supplements trade association the Council for Responsible Nutrition (CRN) reported that evidence from well-designed, randomized clinical trials in humans indicated that the upper safe limit (USL) for creatine monohydrate is 5 grams per day (Regulatory Toxicology and Pharmacology, doi: 10.1016/j.yrtph.2006.05.005).
Source: Cochrane Database of Systematic Reviews Issue 1, 2007 "Creatine for treating muscle disorders" Authors: R.A. Kley, M. Vorgerd, M.A. Tarnopolsky
