Herbal supplements: cause for concern?

More than 1400 herbal products or herbal-derived compounds are commonly commercialised for health uses worldwide (Tyler, 1996). Herbs are considered dietary supplements, and therefore are subjected to a very limited form of regulation, and advertisements normally highlight their potential activities without mentioning any side effect. Also, herbs are generally believed to be ‘natural’, and hence safe. Many nutritional supplements contains herb compounds usually not present in the diet (e.g. Ginko biloba, horse-chestnut), and only 10% of the herbs used in nutritional supplements are commonly present in the food (e.g. garlic, soy, blueberry, green the, ginger, curcuma) (Eisenberg et al., 1993). There is much interest in “alternative natural approaches” in sport. It is appealing for athletes to use ‘natural’ substances with similar activity to ‘pharmacological’ ones in term of improving performance, are not considered doping, and are considered side-effects free (Table 1). Indeed, many herbal dietary supplements marketed on internet are presented as legal alternative to illicit drugs (Denneey et al., 2005).