Journal: International Journal of Sports Medicine. 2007 Apr 13; [E-publication ahead of print]
Authors and affiliation: Hall H, Fahlman MM, Engels HJ. Department of Kinesiology, Elmhurst College, Elmhurst, Illinois, United States.
This investigation examined the effects of Echinacea purpurea on mucosal immunity and the incidence and duration of upper respiratory tract infection (URTI).
32 subjects completed an exercise protocol known to affect mucosal immunity. Saliva was collected prior to and five minutes after completion of exercise testing. Subjects then took either a placebo or Echinacea supplement for 4 weeks and the testing procedure was repeated. Each time, s-IgA concentrations and saliva flow rate were measured and the secretion rate of s-IgA was calculated. In addition, standard logs indicating symptoms of upper respiratory tract infection were completed throughout the study.
Both groups demonstrated significant exercise induced reductions in s-IgA (placebo -69%; Echinacea -43%) and the secretion rate of s-IgA (placebo -79%; Echinacea -53%) at the beginning of the study (p < 0.05).
Following the 4-week intervention, only the control group experienced the post intervention decrease in s-IgA (placebo -45%; Echinacea +7%) and the secretion rate of s-IgA (placebo -45%; Echinacea -7%).
Further, while there was no significant difference in the number of upper respiratory tract infections between groups, the reported duration was significantly different (placebo 8.6 days vs. Echinacea 3.4 days).
The results suggest that Echinacea may attenuate the mucosal immune suppression known to occur with intense exercise and reduce the duration of upper respiratory tract infection that subjects incur.