Lactobacillus helveticus lafti L10 supplementation modulates mucosal and humoral immunity in elite athletes: A randomized, double-blind, placebo-controlled trial

Abstract

To test the influence of probiotic supplementation on humoral immune response, a double-blind, placebo-controlled trial was conducted. Thirty athletes (24 males and 6 females, females: (V)over dotO(2)max 38.2 +/- 4.9 ml.kg(-1).min(-1), age 23.2 +/- 1.4 years; males: (V)over dotO(2)max 57.5 +/- 9.2 ml.kg(-1).min(-1), age 24.0 +/- 2.4 years, mean +/- SD) were randomized either to the probiotic group (Lactobacillus helveticus Lafti L10, 2 x 10(10) colony-forming units) or to the placebo group. Serum and saliva samples were collected at the baseline and after 14 weeks. Total and specific antibacterial antibody levels of IgM, IgG, and IgA classes were determined for different bacteria in the serum, and in saliva, total and specific antibacterial IgA levels were examined. Total IgM was elevated in both probiotic (18%, 15-20%; mean, 90% confidence interval; p = 0.02) and placebo group (35%, 22-47%; p = 0.02), without observed differences in changes between the groups. No significant changes in IgM levels specific for tested bacteria were found. Total IgG level was constant in both groups. A significant (16%, 22.8 to 35%, p = 0.04) reduction of anti-Enterococcus faecalis IgG was noted in the placebo group, in comparison with the probiotic group. There was a substantial decrease in total IgA level in the placebo group, when measured either in serum (15%, 12-18%, p = 0.04) or in saliva (35%, -1.4 to 53%, p = 0.03). Significantly reduced levels of serum anti-lactic acid bacteria IgA antibodies in the placebo group compared with the probiotic group were detected for Lactobacillus rhamnosus LA68 (24%, 5.8-42%, p = 0.02) and for L. rhamnosus LB64 (15%, 2.7-27%, p = 0.02). Probiotic administration could have beneficial effects on systemic humoral and mucosal immune responses.