Effects of Ginseng on Secretory IgA, Performance, and Recovery from Interval Exercise

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Abstract
This study examined the efficacy of ginseng to modulate secretory immunoglobulin A (SIgA), exercise performance, and recovery from repeated bouts of strenuous physical exertion. Using a double-blind, placebo-controlled, randomized design, 38 active healthy adults supplemented their diets with a standardized ginseng concentrate (400 mg.d-1 of G115; equivalent to 2 g of Panax ginseng C.A. Meyer root material) or placebo (lactose) for 8 wk. Before and after the intervention, each subject performed three consecutive 30-s Wingate tests interspersed with 3-min recovery periods under controlled laboratory conditions. SIgA secretion rate (S-SIgA) and the relation of SIgA to total protein were calculated from measures of saliva flow rate (SFR), and absolute SIgA and salivary protein concentrations in timed, whole unstimulated saliva samples collected before and after exercise testing. Peak and mean mechanical power output (W.kg-1) was measured with an infrared-beam optical-sensor array, and exercise recovery heart rate (HRR) was determined electrocardiographically. Twenty-seven subjects (12 placebo, 15 ginseng) completed the study. Compared with rest, S-SIgA, SIgA:protein ratio, and SFR were lower after exercise at baseline (P < 0.05). Similarly, both peak and mean mechanical power output declined (P < 0.01) across consecutive Wingate tests. Postintervention minus preintervention change scores for salivary parameters, exercise performance, and HRR were similar between ginseng- and placebo-treated groups (P > 0.05). These findings do not support the hypothesis that ginseng may affect mucosal immunity as indicated by changes in secretory IgA at rest and after an exercise induced state of homeostatic disturbance. Supplementation with ginseng fails to improve physical performance and heart rate recovery of individuals undergoing repeated bouts of exhausting exercise.