Daily Probiotic’s (Lactobacillus casei Shirota) Reduction of Infection Incidence in Athletes

Abstract

The purpose of this study was to examine the effects of a probiotic supplement during 4 mo of winter training in men and women engaged in endurance-based physical activities on incidence of upper respiratory-tract infections (URTIs) and immune markers. Eighty-four highly active individuals were randomized to probiotic (n = 42) or placebo (n = 42) groups and, under double-blind procedures, received probiotic (PRO: Lactobacillus casei Shirota [LcS]) or placebo (PLA) daily for 16 wk. Resting blood and saliva samples were collected at baseline and after 8 and 16 wk. Weekly training and illness logs were kept. Fifty-eight subjects completed the study (n = 32 PRO, n = 26 PLA). The proportion of subjects on PLA who experienced 1 or more weeks with URTI symptoms was 36% higher than those on PRO (PLA 0.90, PRO 0.66; p = .021). The number of URTI episodes was significantly higher (p < .01) in the PLA group (2.1 ± 1.2) than in the PRO group (1.2 ± 1.0). Severity and duration of symptoms were not significantly different between treatments. Saliva IgA concentration was higher on PRO than PLA, significant treatment effect F(1, 54) = 5.1, p = .03; this difference was not evident at baseline but was significant after 8 and 16 wk of supplementation. Regular ingestion of LcS appears to be beneficial in reducing the frequency of URTI in an athletic cohort, which may be related to better maintenance of saliva IgA levels during a winter period of training and competition.

Salivary Immunoglobulin A and Upper Respiratory Symptoms During 5 Months of Training in Elite Tetraplegic Athletes

“…The criteria for definition of an episode of URS have been published elsewhere. 16 In short, the selfreported occurrence of symptoms like sore or scratchy throat, runny/plugged nose, cough, or fever was noted and their intensity was rated on a 3-point scale (1 = light, 2 = moderate, 3 = severe). Multiplying the intensity score by the number of symptoms and the number of days suffered, a minimum score of 12 was taken to indicate that a URS was present.…”

Nutritional and Physical Activity Interventions to Improve Immunity

“…Furthermore, the proportion of subjects in the placebo group who experienced 1 or more weeks with URTI symptoms was significantly greater (36% higher) than the probiotics group. Gleeson et al 163 also reported a significantly lower total number of URTI episodes, number of weeks with symptoms and gastrointestinal discomfort symptoms in the probiotics group. Although further research is required to fully determine the underlying mechanisms, the above benefits may have implications to the neophyte, as previously discussed.…”

“…Gleeson et al 163 studied a group of endurance athletes who were given a daily probiotics drink (≥ 13×10 9 CFU Lactobacillus casei Shirota) or placebo for 16 weeks during winter training. There were no effects on a range of systemic immune markers apart from salivary SIgA, which decreased in the placebo group but was maintained in the probiotics supplemented group.…”

Immunological aspects of sport nutrition

“…Probiotic actions include modification of the bacterial population (microbiota) that inhabits our gut and modulation of immune function by their interaction with the gut-associated lymphoid tissue, leading to positive effects on the systemic immune system. There are now several well-controlled studies in athletes that have indicated that daily probiotic ingestion results in fewer days of respiratory illness and lower severity of URS [39][40][41][42][43][44][45] and a recent meta-analysis using data from both athlete and non-athlete studies involving 3 451 subjects concluded that there is a likely benefit in reducing URS incidence 46 . Thus, probiotic supplements may reduce URS incidence as well as reducing gastrointestinal discomfort problems (a common complaint of endurance runners).…”