VSL#3 probiotic maternal supplementation affects breast milk composition and newborn faeces microbiota

The infant’s microbiota is acquired during the perinatal period through direct contact with the maternal microbiota during and after delivery. Breastfeeding has been suggested to enrich vaginally acquired lactic acid-producing bacteria of the neonatal gut since the human milk contains viable lactobacilli and bifidobacteria. Microbiological and immunological investigations were performed in order to evaluate the changes induced by VSL#3 probiotic maternal supplementation on breast milk and newborn faeces. Maternal milk was analyzed for factors known to modulate immunological characteristics and the developing microbiota within the gastrointestinal tract (probiotic bacteria, cytokines and immunoglobulins). The functional effects of maternal probiotic intervention on the newborn health were assessed evaluating stool composition in terms of lactobacilli and bifidobacteria content. This pilot double-blind, randomized, placebo-controlled clinical trial enrolled 35 healthy pregnant women four weeks before expected delivery. Participants received daily oral probiotic or placebo supplementation starting from the enrolment until four weeks after delivery. At 3 (T0) and 30 (T30) days after birth, infant stools and milk samples were collected. The amount of lactobacilli and bifidobacteria in breast milk of probiotic treated group was higher compared to controls. However due to the high individual variability of bacterial concentration, this increase did not resulted statistically significant. Noteworthy, the concentration of lactobacilli tended to be higher in the colostrum of the mothers in the probiotic group as compared with those on placebo (p =0.099). At birth the amount of lactobacilli in feces of neonates from VSL#3-treated mothers was significantly higher than in control group (p <0.05). In these samples, the concentration of bifidobacteria tended to be higher as compared with those on placebo. No differences in the presence of VSL#3 Lactobacillus and Bifidobacterium species were observed between groups in both milk and faecal samples. Therefore, our microbiological results exclude a direct colonization of the mammary gland by the supplemented VSL#3 probiotic strains through a suggested migration from the intestine to the lactating mammary gland. TGF-ß values were significantly higher in colostrum from probiotic group in comparison to the control group and increased significantly at T30 only in the probiotic group. IL10 levels were significantly higher in the mature milk from probiotic treated group and IgA levels were significantly higher in colostrum and mature milk from probiotic group. These results suggest that VSL#3 could represent a good supplementation in the diet of pregnant women.