“Nutraceuticals, functional foods, dietary supplements, ergogenic aids, food supplements, performance boosting supplements…”

All the above terms (and more) have been used to entice the unwary (and wary!) athlete to spend money on dietary products that claim to enhance their health and sports performance.

The Oxford English Dictionary definition of supplement is: “Something added to supply a deficiency”. Yet many supplements, or their individual ingredients, are nutrients or food chemicals for which the body does not have an estimated or theoretical requirement. Thus there are clearly other factors that underpin their use by athletes.

Athletes choose to consume a supplement for a number of reasons, including:

• To prevent or treat a perceived nutrient deficiency, especially when requirements for a nutrient are increased by their exercise programme

• To provide a more convenient form of nutrients in situations where everyday foods aren’t practical—particularly to address nutritional needs/goals around an exercise session

• To provide a direct ergogenic (performance-enhancing) effect

• Because they believe every top athlete is consuming it and they can’t afford to miss out.

Before deciding to use a supplement, athletes should always consider the issues of efficacy, safety and legality/ethics associated with the product. Unfortunately, in many cases, specific information is limited. Studies examining the performance-enhancing effects of the enormous array of supplements are relatively few, especially investigations on real-life sports events and elite performers in the field. Studies involving specialised subpopulations such as paralympic athletes are even rarer (personal communication, Jeanette Crosland, BPA consultant dietitian). Therefore decisions about efficacy must often be extrapolated from the best available research rather than clear-cut evidence.

Decisions on safety should examine the possibility of taking a toxic dose of a compound either through indiscriminate supplement use or the belief that “if a little is good, more is better”. However, safety …