Administration of a multistrain probiotic product (VSL#3) to women in the perinatal period differentially affects breast milk beneficialmicrobiota in relation to mode of delivery

Probiotic supplementation to a mother during the perinatal period can have a positive impact on the breast milk composition. The aim of our study was to evaluate the effect of oral supplementation withthe probiotic VSL#3, during late pregnancy and lactation, on breast milk levels of beneficial bacteria andsome functional components (oligosaccharides and lactoferrin) potentially able to have a positive influ-ence on the microbiota. Breast milk microbiota was analyzed by conventional and quantitative real-timePCR. In a double-blind, placebo-controlled, randomized trial, 66 women took daily either the probiotic(n = 33) or a placebo (n = 33). Intergroup analysis demonstrated that the amounts of both lactobacilli andbifidobacteria were significantly higher in the colostrum and mature milk of the mothers taking VSL#3in comparison to those taking placebo. The analysis of bacterial strains and species present in breast milkof VSL#3 supplemented mothers indicated that the administered probiotic microorganisms did not passfrom maternal gut to mammary gland. In women with vaginal delivery, significantly higher amounts oflactobacilli and bifidobacteria were detected in colostrum and mature milk of probiotic treated group incomparison to placebo group, whereas no significant difference was observed between groups in womenwho had caesarean section, neither in colostrum nor in mature milk. Milk levels of oligosaccharides andlactoferrin were similar in placebo and probiotic supplemented groups at all timepoints and regardlessof the mode of delivery. Our results indicate a probiotic-dependent modulation of breast milk microbiotain vaginally delivering women, possibly exerted through a systemic effect.