This chapter will review the supplement practices of athletes, discussing the science behind commonly used supplements. It will be seen that the evidence to support the claims of many products is absent, but that there are specific situations in which athletes may benefit from the use of nutritional supplements. To help simplify the vast array of products on offer to athletes we will continue to use a system that identifies two separate categories or applications of nutritional supplements, classifying these either as dietary supplements or nutritional ergogenic aids. SUMMARY: Athletes and coaches are convinced that a performance edge can be found through the use of sports supplements. In our experience, in order to retain a `real world` credibility, sports scientists need to accept this belief and work within such a framework. This does not mean abandoning critical thinking or downplaying the role of nutrition in optimal performance. Rather, the sports scientist should work with the athlete and coach to allow them to make informed choices about their use of supplements. Ideally, this will mean choosing supplements which have been shown to assist in achieving their specific training and competition goals, and incorporating the appropriate use of these supplements as part of their total nutritional program. In this chapter, we divided supplements into two categories: dietary supplements and nutritional ergogenic aids. We showed that dietary supplements, such as sports drinks, liquid meal supplements, and sports bars, have a variety of well supported roles in helping the athlete to achieve their nutritional goals for optimal performance. While research may continue to refine the composition of these supplements and, perhaps, add to the family of products, the greatest need is for education of athletes to ensure the appropriate use of these dietary supplements. In many cases the information is specific to the individual athlete or sports situation and will require one-to-one counselling. In most situations, the use of the dietary supplement will simply be part of a large plan of optimal sports nutrition or the clinical management of a nutritional disorder. Effective education will not only ensure that the dietary supplement is used correctly, but will highlight the importance of optimal eating strategies. By contrast, the role of most of the commonly sold nutritional ergogenic aids remains unsupported. There is good evidence that caffeine, bicarbonate and creatine offer the potential of performance benefits for specific athletes in specific situations. Well-conducted research is helping to produce better guidelines for the appropriate use of such supplements. Further research is needed to clarify the potential for glycerol and antioxidant vitamins. However, the majority of nutritional ergogenic aids sold to athletes seem unlikely to produce benefits, other than a placebo effect for the athletes that believe in their promises. The supplement industry is an extremely profitable business, relying mainly on testimonials and scientific theories to market the majority of the nutritional ergogenic aids. The production and marketing of such supplements is poorly regulated with respect to quality control and the scientific support for claims. Athletes appear to be unaware of these issues and are vulnerable to problems such as wasting money and overlooking superior performance-enhancing activities. The risk of side-effects and inadvertent doping arising from the use of many supplements is small but real. A mutual benefit for all parties (athletes, supplement manufacturers and sports scientists) will only be achieved through co-operation and pooling of resources to undertake further well-designed research and to support appropriate education programs. However, such research needs to be carefully planned and executed so that it can answer questions that are relevant to athletes and real-life sports competition. Even where the benefits of supplements to athletic performance can be proven, it is important to put their role into perspective. The effects of training and other factors (e.g. inherited talent, equipment, mental preparation and motivation) will provide a greater influence on sports performance than the effects of a dietary supplement or nutritional ergogenic aid. But when these issues are already optimised, as in the case of the well-prepared elite athlete, the effects of supplements might provide another small but significant improvement in performance. The nutrients that can be provided by supplements to greatest effect are fluid and CHO. Other supplements are unlikely to ever provide a substitute for the factors that are basic to sports performance.
© Copyright 2000 Alle Rechte vorbehalten.