Bifidobacterium infantis (bifidobacterium longum subsp. infantis)
Synopsis
Bifidobacterium infantis (also written as B. infantis) is a gram-positive, anaerobic probiotic bacterium that naturally colonizes the gastrointestinal tract of breastfed infants, and is considered one of the most critical early-life microbes for the development of a healthy immune and digestive system. It specializes in metabolizing human milk oligosaccharides (HMOs)—complex sugars in breast milk that are indigestible to humans but selectively fuel beneficial gut bacteria like B. infantis.
This species plays a foundational role in:
- Establishing a healthy infant microbiome
- Promoting gut barrier integrity and reducing intestinal inflammation
- Producing short-chain fatty acids (SCFAs) like acetate and lactate, which lower gut pH and inhibit pathogens
- Supporting immune system development and immune tolerance
- Reducing gas, colic, and diaper rash in breastfed infants
- Potentially lowering risk of allergies, eczema, and autoimmune conditions
B. infantis is particularly dominant in the gut of exclusively breastfed infants and is significantly less prevalent in formula-fed infants or in modern populations with disrupted microbiota due to C-section birth, antibiotic use, or low-fiber diets.
It is primarily used in:
- Infant probiotic supplements, especially for colic, reflux, or eczema
- Formulas enhanced with probiotics
- Maternal probiotic regimens during pregnancy and breastfeeding
- Clinical research for preventing or treating necrotizing enterocolitis (NEC) in premature infants
Historical Use:
Although B. infantis was not isolated and identified until the 20th century, its effects have long been observed through the historical promotion of breastfeeding in traditional medicine. Breast milk was recognized as a protective, immune-boosting food, and modern science has since revealed that this benefit is largely due to the microbial seeding and feeding of species like B. infantis.
Traditional diets rich in fermented foods, whole fibers, and minimal antibiotics helped maintain healthy populations of bifidobacteria across generations. In contrast, modern practices have disrupted this natural microbial inheritance, leading to renewed interest in targeted infant probiotics to restore what was once naturally transferred.
Today, Bifidobacterium infantis is considered a keystone probiotic for infant gut and immune development, and is under increasing study for its lifelong implications in disease prevention, especially in the context of allergy, autoimmunity, and microbiome diversity. It is now a central component in early-life probiotic therapy and maternal-child health protocols.
Body Systems
Appendix (Traditional)
Digestive System (Science)
Immune System (Science)
Intestinal System (Science)