Athletics and Herbal Supplements
Do current products enhance athletes’ health and performance?
Like echinacea, ginseng is taken to augment immunity, but its primary indication is to improve performance. The name ginseng refers to any of approximately a dozen species within the genus Panax, three of which are used most often commercially (P. ginseng is used most frequently, but also P. pseudoginseng and P. quinquefolius). Ginsensosides, from the plant steroids’ saponin subgroup (plant-derived chemicals that in solution produce soaplike foaming when shaken), are the classically recognized bioactive molecules in ginseng. Roots are used most often, typically in dried or powdered form. So-called Siberian ginseng, Eleutherococcus senticosus, is sometimes confused with ginseng and is also frequently used by athletes, although it has different bioactive molecules and may be less effective in the context of performance enhancement.
Unlike echinacea, studies of ginseng or Siberian ginseng in athletic contexts have yielded conflicting results owing to differences in experimental design or outcomes measured. Systematic reviews by Johannah Shergis and colleagues at Royal Melbourne Institute of Technology University, and Michael Bahrke of Human Kinetics along with collaborators at University of Wisconsin-Madison, have concluded that human studies have not convincingly demonstrated any ergogenic benefits of ginseng supplementation in athletes, although supplementation may transiently alter cardiological or pulmonary function. Side effects and prescription drug interactions appear to be more severe and extensive than those associated with echinacea and may include insomnia, gastrointestinal upset and heart palpitations.
Less contentious but more complicated are findings regarding the effects of ginseng supplements on immune function in athletes (Figure 9). From eight different studies that used no fewer than four different ginseng preparations along with a spectrum of exercise modalities, no clear overall patterns emerge. This lack of clarity is probably due to interexperimental variability. Indicators of immune system activity including white blood cell counts, subsets and activities, as well as interactions with signaling molecules associated with the immune system, were variously upregulated, downregulated or unaffected. Conservatively, these facts together indicate ginseng is likely a modulator of immune system activity, but the specific effects that different preclinical factors have on clinical outcomes are poorly understood. Thus, although ginseng is a much more popular herbal supplement than echinacea in the United States and globally, experimental data supporting its use in athletic contexts are currently weak.
Contrasting echinacea studies with ginseng studies reveals that immunological findings from the echinacea studies were more consistent, whereas those from the ginseng studies were more variable (see Figures 6 and 9). There are fewer studies of echinacea’s effects on athletes than ginseng’s effects on athletes, so variation in the effects of ginseng may be better documented than the variation in echinacea’s effects. Echinacea studies mostly focus on aerobic performance, whereas ginseng studies mostly focus on anaerobic, strength athletes’ performance. Although the names echinacea and ginseng encompass multiple species each, studies of them in the context of athletic performance focus on one species each (E. purpurea and P. ginseng, respectively). Why a clearer pattern emerges from the literature on echinacea’s effects on athletes is not known, but the difference in variability may be because the echinacea studies used herbal preparations that were more consistent in species, plant part used and other preclinical factors. Both the echinacea and the ginseng studies drew their participants from diverse populations in terms of age, gender and physical activity levels. Future studies of ginseng and Siberian ginseng preparations may elicit stronger and more consistent findings if both preclinical and clinical factors are controlled better.