DAVIS, J. M., E. A. MURPHY, A. S. BROWN, M. D. CARMICHAEL, A. GHAFFAR, and E. P. MAYER. Effects of Oat β-Glucan on Innate Immunity and Infection after Exercise Stress. Med. Sci. Sports Exerc., Vol. 36, No. 8, pp. 1321–1327, 2004. Exhaustive exercise has been associated with an increased risk for URTI. Oat β-glucan is a mild immune system enhancer and may offset immune suppression associated with exercise stress.
Purpose: To test the effects of oat β-glucan (OβG) on respiratory infection, macrophage antiviral resistance, and NK cytotoxicity.
Methods: Mice were randomly assigned to one of four groups: Ex-H2O, Ex-OβG, Con-H2O, or Con-OβG. OβG was fed in the drinking water for 10 d before intranasal inoculation of HSV-1 or sacrifice. Exercise consisted of treadmill running to volitional fatigue (~140 min) for three consecutive days. Fifteen minutes after the last bout of exercise or rest, mice (N = 24) were intranasally inoculated with a standardized dose of HSV-1. Mice were monitored twice daily for morbidity and mortality. Additional mice were sacrificed after exercise, peritoneal macrophages were obtained via i.p. lavage and assayed for antiviral resistance to HSV-1 (N = 18), and spleens were harvested and assayed for NK cell cytotoxicity (N = 12).
Results: Exercise stress was associated with a 28% increase in morbidity (P = 0.036) and 18% increase in mortality (P = 0.15). Ingestion of OβG before infection prevented this increase in morbidity (P = 0.048) and mortality (P = 0.05). Exercise stress was associated with a decrease in macrophage antiviral resistance (P = 0.007), which was blocked by ingestion of OβG (P < 0.001). There were no effects of exercise or OβG on NK cytotoxicity.
Conclusion: These data suggest that daily ingestion of OβG may offset the increased risk of URTI associated with exercise stress, which may be mediated, at least in part, by an increase in macrophage antiviral resistance.