Effect of Supplementation with Lactobacillus reuteri SGL 01 in Lactating Women on Breast Milk and Neonatal Gut Microbiota: An Exploratory, Randomized, Open-Label Clinical Trial.
Maternal supplementation with L. reuteri SGL 01 did not modify breast milk microbiota but was associated with a modulation of neonatal gut colonization, including an increased abundance of beneficial taxa such as Bifidobacterium, suggesting potential indirect maternal-to-infant microbial effects.
Key Findings
Results
Maternal supplementation with L. reuteri SGL 01 did not produce significant changes in breast milk microbiota composition across any of the bacterial taxa examined.
Taxa assessed included Bifidobacterium spp., Lactobacillus spp., Clostridium spp., and the Bacteroides fragilis group in maternal milk.
Measurements were taken at baseline (T0) and after 30 days of supplementation (T1).
No significant changes were detected in any bacterial group in breast milk of the supplemented group.
The supplemented group consisted of 15 mother-infant dyads.
Results
Neonatal fecal samples from the supplemented group showed significant increases in Bifidobacterium spp. at 30 days.
The increase in Bifidobacterium spp. in the supplemented group was statistically significant (p < 0.001).
Quantitative real-time PCR was used to assess bacterial taxa in neonatal fecal samples.
Samples were collected at baseline (T0) and after 30 days (T1).
No significant change in Bifidobacterium spp. was observed in the control group.
Results
Neonatal fecal samples from the supplemented group showed significant increases in Lactobacillus spp. at 30 days.
The increase in Lactobacillus spp. in the supplemented group was statistically significant (p = 0.029).
This change was observed in 15 mother-infant dyads in the supplemented group.
No significant change in Lactobacillus spp. was reported in the control group of 12 dyads.
Results
Neonatal fecal samples from the supplemented group showed significant increases in Clostridium spp. at 30 days.
The increase in Clostridium spp. in the supplemented group was statistically significant (p = 0.003).
In contrast, the control group showed a slight but significant reduction in Clostridium spp. (p = 0.046).
This represents a divergent trajectory of Clostridium spp. between supplemented and control neonates.
Results
No significant microbial changes were observed in the neonatal fecal microbiota of the control group, except for a slight reduction in Clostridium spp.
The control group comprised 12 mother-infant dyads who received no supplementation.
The reduction in Clostridium spp. in the control group was statistically significant (p = 0.046).
Bifidobacterium spp., Lactobacillus spp., and Bacteroides fragilis group did not show significant changes in the control group.
Methods
The study design was an exploratory, prospective, open-label randomized clinical trial involving lactating mothers of full-term, exclusively breastfed infants.
Twenty-seven mother-infant dyads completed the study: 15 in the supplemented group and 12 in the control group.
The supplemented group received daily L. reuteri SGL 01 at a dose of 1 × 10⁹ CFU for 30 days.
The control group received no supplementation.
Bacterial taxa were assessed using quantitative real-time PCR in both breast milk and neonatal fecal samples at T0 and T1.
Pagliarini E, Poli C, Martini S, Cimatti A, Di Gioia D, Corvaglia L. (2026). Effect of Supplementation with Lactobacillus reuteri SGL 01 in Lactating Women on Breast Milk and Neonatal Gut Microbiota: An Exploratory, Randomized, Open-Label Clinical Trial.. Nutrients. https://doi.org/10.3390/nu18050794