Probiotic restores gut microbiome as bifidobacteria decline in breastfed infants

Probiotic supplementation can help restore the gut microbiomes of infants who have been exclusively breastfed, new research reveals. These babies are experiencing a decline in beneficial gut bacteria, specifically Bifidobacterium infantis, in high-resource regions, according to recent trends. 

The publication in mSphere shows that B. infantis EVC001 supplementation could restore essential bacteria in two- and four-month-old babies, while boosting numbers in older infants at various doses. 

The researchers note that no studies to date have shown that B. infantis has been successful in breastfed newborns.

They explain that thanks to the probiotic thriving on human milk oligosaccharides (HMOs), it persists in the gut. This suggests that short-term supplementation with different doses can have long-lasting benefits for breastfed infants, as they are not simply passed through the gut.

“The study shows that it’s not too late to restore a healthy gut microbiome in breastfed infants. B. infantis can successfully take hold even after the newborn period,” says corresponding study author Jennifer Smilowitz, Ph.D., assistant professor of Cooperative Extension in the Department of Nutrition, University of California, Davis, US.

A healthy early-life gut microbiome is essential for gut health, immune development, and overall health, note the researchers. However, in the US and Europe, Bifidobacterium is no longer dominating the infant gut microbiome, causing increasing health risks.

The company Persephone Biosciences recently found that 76% of US infants’ gut microbiomes put them at risk for developing allergies, asthma, eczema, and dermatitis due to a deficiency in Bifidobacteria.

Proven lasting effects

The researchers were motivated to test whether the previously tested benefits of B. infantis and human milk in newborns could be replicated in older exclusively breastfed babies. 

The 9-week randomized controlled trial tested different doses of the probiotic — high, medium, and low — alongside a placebo. No differences in fecal B. infantis levels were noted among these dose groups.

Forty infants’ stool samples before, during, and after taking the supplement were examined to see how microbiomes changed. These were collected on study days seven, 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,” the study details.

“On day 28, fecal B. infantis levels were significantly higher in infants who received any (low, medium, or high) dose compared with baseline. The abundance of fecal Bifidobacteriaceae significantly increased nearly two-fold in response to B. infantis EVC001 supplementation.”

Additionally, the team also tested the impacts of commercially available low doses of B. infantis against the newborn study, which used a high dose of the probiotic.

Regardless of dose, the probiotic supplementation led to B. infantis colonization until at least one month post-supplementation.

“These findings suggest that B. infantis supplementation can restore the infant gut even past the newborn stage,” says Smilowitz. “Unlike many probiotics that disappear once supplementation stops, B. infantis was able to take hold and remain in the gut when paired with human milk, which naturally contains the HMOs it needs to grow.” 

“This means even short-term supplementation at a range of doses may have lasting benefits for breastfed infants. The finding that all tested doses were effective suggests this approach may be adaptable to real-world settings where access, timing, or dose can vary.”

In other research developments, a study revealed how a child’s early gut microbiome may influence their risk of developing depression, anxiety, or other internalizing symptoms during childhood.