New Study Shows Significant Changes to Infant Fecal pH Over Last 100 Years

Evolve BioSystems discovers dramatic shift indicating generational loss of good bacteria in baby’s gut microbiome.  


DAVIS, Calif., March 7, 2018 -- Evolve BioSystems today announced new research that connects elevated infant fecal pH levels to a profound change in the infant gut microbiome, including the disappearance of a beneficial bacterium that may be key to short and long-term health. Over the past 100 years, the average pH level of a baby’s stool, which can indicate the type of bacteria in the baby’s gut, has undergone an alarming increase from pH 5.0 to 6.5. The study, published in the American Society for Microbiology journal mSphere, connects this rise in pH to a generational loss of Bifidobacterium, a critical gut bacteria during infancy, and an accompanying increase in a number of harmful bacteria.  

The complete study, “Elevated Fecal pH Indicates a Profound Change in the Breastfed Infant Gut Microbiome Due to Reduction of Bifidobacterium over the Past Century,” can be accessed here.

Stark rise in infant fecal pH from 1926-2017 tied to disruption of infant gut microbes

A review of 14 clinical studies published between 1926 and 2017, representing hundreds of healthy breastfed infants, showed a change in fecal pH from 5.0 to 6.5 over this time period. The authors attribute this trend to an observed reduction of Bifidobacterium in the infant gut, along with an increase in potentially harmful bacteria such as E. coli and Clostridia, resulting in “dysbiosis”, a potentially detrimental imbalance of the gut microbial ecosystem.

According to study co-author, Dr. Jennifer Smilowitz, Associate Director of the Human Studies Research Program for the Foods for Health Institute at UC Davis, “These alarming changes to the infant gut microbiome and thus, gut environment, may be due to modern medical practices like antibiotics, C-sections, and formula feeding. These are all potentially life-saving medical practices, but have unintended consequences on the infant gut microbiome. As a result, certain pathogenic bacteria—those linked to higher risk of health issues such as colic, eczema, allergies, diabetes and obesity¾ thrive. The need for clinicians to have a quick and reliable method to determine Bifidobacterium levels in baby’s gut, and an effective way to replace the right Bifidobacterium to correct dysbiosis when detected, are the critical next steps for infant health.”

Restoring the infant gut to its natural state

In December 2017, Evolve BioSystems published results of a landmark clinical trial in mSphere, showing that Evivo®, an activated form of B. infantis, produced rapid, substantial, and persistent improvements in the gut microbiome of breastfed infants. Evivo is the only baby probiotic clinically proven to restore the levels of Bifidobacterium to baby’s gut, reduce potentially harmful gut bacteria by 80 percent, and return fecal pH to levels seen historically.

“This steady increase in the fecal pH of infants over the past several generations has largely gone unnoticed by the medical community, but looks to be an indication of a major disruption of the infant gut,” said David Kyle, Ph.D., Chief Scientific Officer and Executive Chairman at Evolve BioSystems, Inc. “This may be a significant contributor to the incidence of allergic and autoimmune disorders. We are making progress in learning how to detect infant gut dysbiosis and restore the gut to its natural state through the introduction of very specific probiotics.”

For more information about Evivo, please visit

Tracy Shafizadeh