Doctors have expressed concern after a body builder who took high doses of "energy pills" suffered a major stroke.

The 33-year-old baggage handler had been taking MaHuang extract, caffeine and ephedrine extract, combined with large quantities of creatine.

Creatine has become popular among athletes tempted by claims that it can increase power without the side-effects associated with anobolic steroids.

Doctors at the neurology department at Lariboisiere Hospital in Paris, writing in the Journal of Neurology, Neurosurgery and Psychiatry, said it was a unique case.

Dr Katayoun Vahedi said: "This first case of an extensive cerebral infarct (stroke) in a young sportsman consuming large doses of MaHuang extract and creatine should alert the sport community to the possible adverse effects of energy supplements, particularly when used in multiple combination."

The patient had taken the combination of drugs approximately six weeks before the stroke.

"We didn't find any other cause for his stroke," added Dr Vahedi.

Struggling for explanation

However, the fact that this is a single case among thousands of users of such supplements worldwide does not suggest a major link between the stroke and the drugs, although the particular combination may be unusual.

But the absence of other risk factors like drinking, smoking and obesity mean doctors are struggling to come up with any other explanation.

One of their theories is that the high dose of caffeine may have boosted the stimulant qualities of ephedrine, and affected the heart.

Dr Vahedi said: "It is important for the medical community and also for the sporting community to be aware of this, particularly when combinations of drug are used."

Although some studies have suggested that taking creatine yields no real performance gain, no major side-effects of use have been detected.

MaHuang, a traditional Chnese herbal medicine, and a source of the stimulant ephedrine, has been touted as a weight loss drug, with moderate success in small studies.