Randomized, placebo-controlled trial reveals the impact of dose and timing of Bifidobacterium infantis probiotic supplementation on breastfed infants’ gut microbiome

A dysfunctional gut microbiome has become increasingly common in infants born in high-income countries as Bifidobacterium strains no longer dominate the gut microbiome.

 

Probiotics containing Bifidobacterium infantis have been used in breastfed newborns to successfully restore the gut microbiome; however, no studies to date have demonstrated this effect in older breastfed infants whose gut microbiomes are transitioning toward stability and maturity. This is a 9-week randomized controlled trial wherein 2–4 months old exclusively breastfed infants (n = 40) received 0 CFU/day B. infantis EVC001 (placebo), 4.0 × 10⁹ CFU/day B. infantis EVC001 (low), 8.0 × 10⁹ CFU/day B. infantis EVC001 (medium), or 1.8 × 10¹⁰ CFU/day B. infantis EVC001 (high) in equal allocation for 28 consecutive days beginning on day 8. Stool samples were collected on study days 7, 10, 14, 21, 28, 35, 42, and 63.

 

Fecal B. infantis levels were significantly higher in all supplement groups compared with placebo on day 28 and day 63. On day 28, fecal B. infantis levels were significantly higher in infants who received any (low, medium, and high) dose compared with baseline. The abundance of fecal Bifidobacteriaceae significantly increased nearly 2-fold in response to B. infantis EVC001 supplementation.

 

No matter the dose, probiotic supplementation with B. infantis in 2- to 4-month-old exclusively breastfed infants resulted in colonization until at least 1 month post-supplementation.

 

 

For more information:

O'Brien CE, Frese SA, Cernioglo K, Damian-Medina K, Mitchell RD, Casaburi G, Melnyk RA, Henrick BM, Smilowitz JT. 0. Randomized, placebo-controlled trial reveals the impact of dose and timing of Bifidobacterium infantis probiotic supplementation on breastfed infants’ gut microbiome. mSphere 0:e00518-25. DOI: https://doi.org/10.1128/msphere.00518-25