Use of K12 in supporting the mucosal immune function of active young subjects: A randomised double-blind study.

Introduction: Upper respiratory tract infections (URTI) are the most common illnesses affecting athletes, causing absences from training and competition. Salivary immunoglobulin A (sIgA) is the main immune factor in saliva, and a consistent association between low concentrations of sIgA and an increased incidence of URTIs has been reported. The oral probiotic K12 has been suggested to have the potential to improve oral diseases and mucosal barrier function.