Effect of Lacticaseibacillus paracasei N1115 on Immunomodulatory and Gut Microbial Composition in Young Children: A Randomized, Placebo-Controlled Study

Abstract

Lactobacillus paracasei N1115 (Lp N1115) was isolated from fermented milk products. The administration of Lp N1115 is safe and well tolerated in Chinese children, but its effectiveness among young Chinese children is still unclear. To investigate the efficacy of Lp N1115 as a probiotic to enhance gut development in Chinese infants and toddlers born by cesarean section, 109 healthy and cesarean-delivered infants aged 6-24 months were recruited for a 12-week randomized, placebo-controlled trial, with 101 finally completing the study. Saliva and stool samples were collected and detected at weeks 0, 4, 8, and 12 of the intervention. Statistical analyses were performed by using a per-protocol (PP) approach. After 12 weeks of intervention, the fecal pH in the control group increased (p = 0.003), while the fecal pH in the experimental group did not change. Salivary cortisol decreased from baseline in the experimental group (p = 0.023), while the control group showed little change. In addition, Lp N1115 increased the fecal sIgA content of infants aged 6-12 months (p = 0.044) but had no obvious effect on fecal calprotectin and saliva sIgA. At week 4, the increase in Lactobacillus relative to baseline was higher in the experimental group than in the control group (p = 0.019). Further analysis showed a trend toward a higher detection rate of Lactobacillus in the experimental group than in the control group (p = 0.039). In conclusion, Lp N1115 was able to enhance the content of Lactobacillus and maintain fecal pH levels. Its beneficial effects on gut development were more obvious in 6-12-month-old infants.

Keywords: Lacticaseibacillus; cesarean section; probiotic; young children.

Figure 1

Experimental procedure.

Figure 2

Fecal pH changes throughout the intervention. (a) Fecal pH changes of all participants; (b) Fecal pH changes of 6–12-month-old subgroup; (c) Fecal pH changes of 13–24-month-old subgroup.

Figure 3

Changes in salivary cortisol from baseline. (a) salivary cortisol changes of all participants; (b) salivary cortisol changes of 6–12-month-old subgroup; (c) salivary cortisol changes of 13–24-month-old subgroup.

Figure 4

Changes in sIgA in feces and saliva compared with baseline. (a) fecal sIgA changes of all participants; (b) fecal sIgA changes of 6–12-month-old sub-group; (c) fecal sIgA changes of 13–24-month-old subgroup; (d) saliva sIgA changes of all participants; (e) saliva sIgA changes of 6–12-month-old sub-group; (f) saliva sIgA changes of 13–24-month-old subgroup.

Figure 5

Changes in FC and AAT compared with baseline. (a) FC changes of all participants; (b) FC changes of 6–12-month-old sub-group; (c) FC changes of 13–24-month-old subgroup; (d) AAT changes of all participants; (e) AAT changes of 6–12-month-old sub-group; (f) AAT changes of 13–24-month-old subgroup.

Figure 6

Changes in the relative abundance of Lactobacillus compared with baseline. (a) relative abundance of Lactobacillus changes of all participants; (b) relative abundance of Lactobacillus changes of 6–12-month-old subgroup; (c) relative abundance of Lactobacillus changes of 13–24-month-old subgroup.