Lactobacillus casei Shirota May Decrease Risk of Upper Respiratory Infection
Prolonged and extensive physical activity, such as training for and running a marathon, may increase the risk of upper respiratory infections. A new study suggests that consumption of Lactobacillus casei Shirota (LcS) may help improve immune and inflammatory response in marathon runners.
Researchers from Federal University of São Paulo conducted the study, which included 42 male marathon runners. Participants were assigned to consume a fermented milk containing 40 billions of LcS or a placebo unfermented milk for 30 days prior to running a marathon.
Immune and inflammatory parameters in nasal musoca and serum, concentrations of salivary secretory IgA, and antimicrobial peptides in saliva were measured at baseline, and immediately, 72 hours, and 14 days after the marathon.
Participants in the control group had higher levels of proinflammatory cytokines in nasal mucosa and serum immediately after the marathon, compared to participants in the LcS group. They also had lower levels of salivary secretory IgA and antimicrobial peptides. Reduced levels of salivary secretory IgA are associated with an increased risk of upper respiratory symptoms.
The study was published on July 22, 2019 in the journal Nutrients.