Bifidobacterium infantis (B. infantis) is a specific type of beneficial bacteria that naturally resides in the infant gut. It is recognized as a significant component of a healthy early-life microbiome.
Biological Profile
B. infantis belongs to the Bifidobacterium genus, a group of Gram-positive, anaerobic microorganisms. It is uniquely adapted to thrive in the human neonatal gut. A distinguishing characteristic of B. infantis is its exceptional ability to utilize human milk oligosaccharides (HMOs) as a primary food source. It possesses specialized systems to break down HMOs, complex sugars abundant in breast milk but indigestible by the infant.
Crucial Role in Infant Development
B. infantis contributes to infant development through several mechanisms within the gut. It metabolizes HMOs into beneficial short-chain fatty acids (SCFAs), such as acetate and lactate. These SCFAs help lower the gut’s pH, creating an environment less favorable for the growth of potentially harmful bacteria. It also strengthens the intestinal barrier, preventing the entry of harmful substances. Furthermore, B. infantis interacts with the developing immune system, helping to educate and mature immune responses. This interaction may contribute to reducing the risk of conditions like allergies by promoting immune tolerance. By outcompeting harmful microbes, B. infantis helps maintain a balanced gut environment.
Sources and Acquisition
Infants primarily acquire B. infantis through vertical transmission from their mothers. This transmission can occur during passage through the birth canal and through exposure to the mother’s microbiota.
Breast milk is a significant source that supports the colonization and growth of B. infantis in the infant’s gut. Human milk oligosaccharides (HMOs) in breast milk act as prebiotics, selectively feeding and promoting the growth of B. infantis. This specialized nutrient source gives B. infantis a competitive advantage, enabling it to become a dominant bacterium in the gut of breastfed infants. While vertical transmission and breast milk are primary routes, other environmental exposures can also play a role in early colonization.
Addressing Deficiencies
A notable concern in many industrialized countries is the reduced presence or absence of B. infantis in infants, which can lead to an imbalance in the gut microbiome, often termed dysbiosis. This deficiency can result from factors such as C-section births, early antibiotic use, and formula feeding. When B. infantis is lacking, infants may experience suboptimal gut function and a potentially compromised immune system.
To address this deficiency, targeted probiotic supplementation with B. infantis is a common approach. Administering specific B. infantis strains can help re-establish a healthy gut microbiome. Studies show supplementation can increase Bifidobacterium species, improve beneficial acid production, and support digestive function. This intervention aims to restore the protective and developmental benefits that B. infantis provides.