Athletics and Herbal Supplements
Do current products enhance athletes’ health and performance?
The extent of athletes’ herbal supplement use is unclear. Part of the problem is that few studies address this topic. Surveys of athletes’ supplement use exist, but herbal supplements are often relegated to a category called “other.” And when supplements are identified as a separate category, the specific supplements used are often unreported. In the United States alone, 17 to 61 percent of athletes reported using herbal supplements, although the categorization of herbal supplement varied across surveys, and this likely explains the huge discrepancy. Although these numbers should be interpreted cautiously, it appears safe to conclude that athletes’ use of herbal supplements is higher than in the general public.
Purportedly performance-enhancing herbs include those that benefit both endurance and strength athletes, such as ginseng (Panax species or Eleutherococcus senticosus), ephedra (Ephedra sinica) and arctic root (Rhodiola rosea). They also include herbs such as caltrop (Tribulus terrestris) that may primarily benefit strength athletes (see Figure 5). Ephedra and ginseng are also considered central nervous system stimulants along with guarana (Paullinia cupana). Herbs taken primarily to boost immune function include echinacea (Echinacea species), elderberry (Sambucus nigra) and milk vetch (Astragalus species). Other herbs, such as caltrop, soy (Glycine max) and sarsaparilla (Smilax species), are believed to contain plant-produced compounds capable of modulating anabolic steroidal pathways. And some supplements are promoted as having more specialized functions, such as the supposed metabolism-enhancing fungus, Cordyceps sinensis. Still others are treated as multipurpose food ingredients, for example, the cyanobacterium Spirulina (Spirulina species).
The organisms mentioned above demonstrate that these supplements are taxonomically diverse and include flowering, seedless vascular and nonvascular plants, fungi and algae with distinct evolutionary histories. The bioactive molecules attributed to each taxon are equally diverse, although most are classified as secondary metabolites, chemical compounds produced by living organisms but not required for their primary functions. Many herbs used in sports supplements or energy drinks contain alkaloids—small, nitrogen-based compounds that encompass many notorious naturally derived molecules, from morphine to cocaine—that act as stimulants. Examples include caffeine from the kola plant (Cola species), ephedrine and pseudoephedrine from ephedra, guaranine from guarana, and theobromine and theophylline from the chocolate plant (Theobroma cacao).
Current research on the dozens of botanical dietary supplements used by athletes all suffer from the problems outlined above. Two of the most well known of these supplements, echinacea and ginseng, will serve as representative examples.