Cytokines in human milk promote inflammatory responses and help stimulate development and regulate the immune system in infants.
Probiotic supplementation in pregnant and lactating mothers are promising options for altering the composition of immune components in breast milk and preventing the development of allergies in infants and children.
At present, the benefits of probiotic supplementation on human milk cytokines are inconclusive, and most studies only analyse single strains or a limited range of cytokines.
Hence for this study, researchers performed a pilot trial measuring 27 cytokines in mothers supplemented with three probiotic strains (Lactobacillus casei LC5, Bifidobacterium longum BG7, and Bacillus coagulans SANK70258).
The study was funded by Japanese infant and maternal nutrition company Bean Stalk Snow, and involved researchers at the University of Yamanashi.
Findings were published in the Nutrients journal.
Data collection and analysis
The open-label pilot study recruited 60 lactating women from Tokyo.
Participants voluntarily join either the probiotic group (n = 41) or the control group (n = 19).
The probiotic group received three probiotics tablets daily after breakfast containing L. casei LC5 (5 × 109 CFU), B. longum BG7 (5 × 109 CFU), and B. coagulans SANK70258 (2 × 108 CFU) for two months (between one to three months postpartum).
For both groups, breast milk samples were collected at month one, two and three of postpartum, and 27 cytokines were measured, including interleukin (IL), normal T cell expressed and secreted (RANTES), tumor necrosis factor-α (TNF-α), and vascular endothelial growth factor (VEGF) levels.
Some cytokines have anti-inflammatory properties (good) while some are pro-inflammatory (bad).
Researchers used mature milk (one month or later) instead of colostrum (0-7 days) because it was more suitable for observing the effects of probiotic supplementation on mothers, even though colostrum would contain more immunologically active molecules.
Bean Stalk Snow manufactured and sold the test formulation in this study.
L. casei LC5 is isolated from cheese and is involved in anti-inflammatory activity. B. longum BG7 is isolated from infant faeces and suppresses IL-8 production, helping prevent bacterial infection. B. coagulans SANK70258 is isolated from green molt, and improves the intestinal environment.
The findings showed anti-inflammatory cytokines like IL-10 were significantly higher in the probiotic group than in the control group at one and two months.
IL-10 plays a key role as a regulatory molecule in both innate and adaptive immune responses, contributing to developing immune tolerance and suppressing tissue inflammation.
VEGF levels were also significantly higher in the probiotic group than in the control group at one month.
In the probiotic group, pro-inflammatory cytokines such as IL-6 decreased significantly from one to two months.
The results suggest that short-term probiotic intake in lactating mothers improves cytokine levels in breast milk.
“Our study suggests that supplementation with a probiotic mixture during lactation, but not during pregnancy, modified the cytokine profile in mature milk,
“As dietary supplements are already popular among lactating women in Asian countries, this study also provides a simple regimen for implementing probiotic supplementation, one that does not require administration of probiotics to the infants,” researchers said.
Limitations and recommendations
However, they acknowledged several limitations in the current study including environmental factors such as ethnic factors, geographic location, dietary patterns, socioeconomic status, and psychosocial conditions which were not taken into account and may influence cytokine levels in breast milk.
In addition, mothers who chose the probiotic group were more concerned about their health, and their diets and lifestyles may have influenced the results.
n-3 PUFA supplements including fish oil are becoming increasingly popular in pregnant and lactating women in Japan and other East Asian countries, and their usage may affect immune components in breast milk.
Researchers recommend future randomised, placebo-controlled studies to support these results, as well as include food frequency questionnaires and dietary recall to monitor dietary patterns in lactating women.
“Probiotic Supplementation and Human Milk Cytokine Profiles in Japanese Women: A Retrospective Study from an Open-Label Pilot Study”
Authors: Tomoki Takahashi, et al.