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

Nutrients. 2023;15(8)
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Cesarean section (C-section) is one of the most common obstetrical procedures, and China is among the countries with the highest C-section rates in the world. Lactobacillus is one of the well-known and most studied probiotics and has a broad distribution in the human oral cavity, genitourinary tract, gastrointestinal tract, and milk. The aim of this study was to investigate the efficacy of Lp N1115 as a probiotic on immunomodulatory and gut microbial composition in Chinese infants and toddlers born by C-section. This study was a single-centre, randomised, triple-blind placebo-controlled trial. Healthy infants born by C-section were recruited at the age of 6–24 months and divided into two age groups: 6–12 months and 13–24 months. Infants and toddlers were randomly assigned to either the experimental group (Lp N1115 group) or the placebo-control group. Results showed that Lp N1115 can help maintain the intestinal pH of infants aged 6–24 months after C-section, improve immune function, and promote the proliferation of Lactobacillus. Furthermore, Lp N1115 could increase faecal secreted immunoglobulin A levels and, to some extent, reduce cortisol levels in infants and children. Authors conclude that the beneficial effects of Lp N1115 on gut development were more obvious in 6–12-month-old infants.


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.

Lifestyle medicine

Patient Centred Factors : Mediators/Gut microbiota
Environmental Inputs : Microorganisms
Personal Lifestyle Factors : Nutrition
Functional Laboratory Testing : Saliva ; Stool
Bioactive Substances : Probiotics

Methodological quality

Jadad score : 4
Allocation concealment : Yes