Contamination issues

One of the key factors that elite athletes need to consider in negotiating the complex world of supplements and sports foods is whether the consumption of these products could lead to an inadvertent case of doping. Following the wave of nandrolone findings in the late 90s, several studies have sought to explore the extent of contamination. In 2000–01, the International Olympic Committee (IOC) funded an extensive research project using the then IOC-accredited laboratory in Cologne to analyse independently 634 non-hormonal nutrition supplements purchased across 13 countries. This pivotal research confirmed the contamination issue, with 15% (94 products) being found to contain undeclared steroids banned by the World Anti-Doping Agency (WADA, www.wada-ama.org). Altogether, 289 samples (21% positives) were from companies that were known to sell steroids/prohormones but, perhaps more worrying, 345 samples (9.6% positives) came from companies that did not sell steroids/prohormones.

Results of the IOC Cologne Study continue to be confirmed, illustrating that the issue of contamination is still around. In 2007, HFL Sport Science (a WADA-experienced laboratory, part of the Quotient Bioscience group) in the UK analysed 58 supplements purchased through standard retail outlets in the USA. They found that 25% were contaminated with prohibited steroids and 11% were contaminated with prohibited stimulants (personal communication, Catherine Judkins, HFL Sport Science). In 2008, HFL Sport Science followed this up with the analysis of 152 products purchased from standard retail outlets in the UK and found that over 10% were contaminated with steroids and/or stimulants (personal communication, Catherine Judkins, HFL Sport Science).

The assumption has generally been that the presence of WADA-prohibited substances is the result of inadvertent contamination of raw materials and/or cross-contamination during the manufacturing or packaging process rather than deliberate adulteration of the products in an attempt to increase the supplement’s effectiveness. Consequently, the amounts of steroids detected have been extremely variable, even within a single batch, but have generally been extremely small. However, very low levels of contamination (measured in parts per billion) can cause positive drug tests in an elite athlete at a level much lower than acceptable impurity levels (typically around 0.01%) in good manufacturing practice regulations. It is important to note that, although this minimal amount of contamination could produce dire consequences for an athlete competing under the WADA code, in most cases, this amount is unlikely to cause detrimental health problems for the general consumer. There are daily food product withdrawals and recalls because of mislabelling and undeclared allergens. This, together with concerns about impurities and contamination from medicine residues, insects and small pieces of metal and plastic, shows that inadvertent contamination is not just a problem for sports nutrition products.

The inadequate regulation of dietary supplements means there is no way for consumers to know what many supplements actually contain or how pure the product and its ingredients are. Manufacturers with good-quality controls and banned substance testing are better able to control the risk. The inception of the WADA code and the implications of strict liability means that an athlete is held responsible for whatever is in their body irrespective of how it got there. Therefore, athletes who compete under the WADA code should be extremely cautious about using supplements and always work with a qualified professional on risk minimisation of supplement use.

BJSM supplement series

There are many reviews on supplementation in athletes, some of which are very good. Our aim is not to replicate these, but to give a series of very brief overviews, some of which will be by experts in the field. Our main aim is simply to demystify some of the many supplements on the market in order to provide a useful resource for athletes, sport and exercise enthusiasts, along with allied professionals such as nutritionists, coaches, physiotherapists and doctors. Some research citations for each topic (or comment on the lack of them) will be provided for those who wish to investigate further. When feasible, practical advice will be given about dosage and timing. Needless to say, this advice will be based on the best available sources at the time. (The authors cannot be held responsible for the failure of any specific dose to improve performance, etc.)

This series will cover a range of the supplements commonly used by athletes. Table 1 provides an example of 102 supplements that will be included in the series. Some of these will be complete products, whereas others will be the individual substances that make up the many poly-ingredient supplements on the market. Our commentaries are planned to be set out in alphabetical order. However, we will make allowances for comments on any supplement that has recently become a “hot topic” rather than wait for its place some time down the line. Articles will be cross-referenced to allow for those supplements that are popularly known to athletes by more than one name.

With such a vast range of supplements and ingredients marketed for athletes, we simply will not be able to cover them all and, for some, it will just be a brief mention or cross-reference. Furthermore, owing to time and space constraints, these articles will deal specifically with the effects of these supplements on exercise and sport-related health and performance issues rather than general health or clinical issues.