Indianapolis

Nutritional supplements are riddled with contaminants such as steroids and other banned substances, scientists heard at the annual meeting of the American College of Sports Medicine (ACSM) in Indianapolis on 2–5 June. But a new initiative in the Netherlands could serve as a model for countries that want to give their athletes a safer choice, they said.

Supplements contain ingredients such as vitamins, minerals and amino acids. But for several years contaminants have been suspected of causing some athletes to test positive for banned substances, leading authorities to recommend that sportsmen and women stay off them altogether.

Credit: SOURCE: INT. J. SPORTS MED. 25, 124–129; 2004

A recently published study, conducted at the German Sport University in Cologne, tested 634 supplements bought in 13 different countries between 2000 and 2001 (H. Geyer et al. Int. J. Sports Med. 25, 124–129; 2004). Although their labels claimed they were hormone-free, nearly 15% of the supplements tested positive for anabolic steroids (see Graph). The authors say that this could be the result of cross-contamination from improperly cleaned machinery, rather than intentional spiking.

In 2002, a study by the Netherlands Centre for Doping Affairs found that nearly a quarter of samples from supplements that Dutch athletes intended to use while training for the Utah Olympic Games were likewise contaminated.

Tennis star Greg Rusedski was cleared of drug charges earlier this year after he said that he had taken contaminated supplements unwittingly. Credit: AAP/PA

Given that athletes continue to use supplements, several countries have taken steps to catalogue clean sources. Last year, for example, the German Sport University tested 200 supplements approved for medicinal use and found that none contained detectable levels of steroids. “This is clearly down to good manufacturing processes,” says Wilhelm Schänzer, head of the Cologne Anti-Doping Institute, who is planning wider studies.

The biggest push to clean up supplements is going on in the Netherlands, the conference was told. The NZVT (Netherlands Security System for Nutritional Supplements in Élite Sports), launched last November, sets manufacturing standards for participating companies — of which there are 25 so far. It then tests each batch of supplement and posts the results online. Random tests are also carried out at later dates. More than 125 batches have been tested so far, all of which are listed on the website as clean.

Scientists at the meeting were impressed by such moves. But they remained concerned that athletes see supplements as performance boosters, despite the lack of evidence for this. It has never been proven that supplements do more good for an athlete than a balanced diet, said Ron Maughan, a nutrition expert from the University of Loughborough, UK.

Exercise psychologist James Whitehead from the University of North Dakota, Grand Forks, was one of many who complained that some exhibitors at the meeting were pushing supplements. “It has been a problem here for years,” he said. Karl Fischer, who will soon become president of the ACSM, said that the claims of advertisers are checked by the college for sexism and slander but not for scientific content. “But this will change,” he promised.

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