There is an increasing interest in the intestinal and immunological effects of probiotics. The aim of the present study is to evaluate the tolerance and beneficial effects in healthy adults of the strain, Lactobacillus salivarius CECT5713 isolated from breast milk. A phase II, randomized, double-blinded, placebo-controlled human clinical trial was carried out in 40 healthy adults. The Probiotic group received a daily dose of 2 x 10(8) CFU of L. salivarius CECT5713 in capsules during 4 weeks while volunteers of the control received only a placebo. Gastrointestinal and immunological parameters were analyzed. Results showed that L. salivarius CECT5713 was well tolerated and no adverse effects were detected. Consumption of the probiotic strain increased fecal lactobacilli counts (7.9+/-0.1 vs. 7.05+/-0.2 CFU/g feces, P=0.001). Also, an improvement in the frequency of defecation (P=0.04) was observed. Probiotic treatment induced significantly the percentage of NK cells and monocytes, as well as the plasmatic levels of immunoglobulins M, A and G, and the regulatory cytokine IL-10 (72.3+/-11.7 in probiotic group vs. 27.3+/-6.4 pg/mL in control group, P<0.01). Thus, it can be concluded that daily administration of L. salivarius CECT5713 to healthy adults is safe and improve gut microbiota and different parameters related to immune response.
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