Bifidobacterium Infantis Bi45
Also known as: Bifidobacterium infantis, B. infantis, B. infantis Bi45, Bifidobacterium longum subspecies infantis
Overview
Bifidobacterium longum subspecies infantis (B. infantis) is a Gram-positive, anaerobic bacterium naturally found in the human gut, particularly abundant in breastfed infants due to its ability to metabolize human milk oligosaccharides (HMOs). As a probiotic supplement, it is primarily utilized to enhance gut health, especially in neonatal populations. Its main applications include the prevention of necrotizing enterocolitis (NEC) in preterm infants, reduction of intestinal permeability, and modulation of immune responses. Extensive research, including numerous randomized controlled trials (RCTs) and meta-analyses, supports its clinical efficacy and safety in these vulnerable populations. While the specific strain Bi45 is less studied independently, it is expected to share the broad benefits and characteristics of the B. infantis subspecies.
Benefits
The primary and most robust benefit of B. infantis is the prevention and reduction of necrotizing enterocolitis (NEC) incidence in preterm infants. Meta-analyses consistently show statistically significant reductions in NEC rates, ranging from approximately 30-50% relative risk reduction, compared to placebo (p < 0.05). This benefit is strongly supported by high-quality evidence from multiple RCTs. B. infantis also significantly decreases intestinal permeability and improves gut barrier function, demonstrated by increased expression of tight junction proteins (claudin 4, occludin, ZO-1) in vitro and in animal models. It establishes a competitive colonization advantage in the infant gut, leading to a healthier microbiota profile with fewer pathogenic bacteria. Secondary benefits include a potential reduction in late-onset sepsis in preterm infants, though this evidence is less consistent and requires further validation. It may also modulate immune responses, potentially reducing inflammation, but its clinical significance in humans is still under investigation. The most robust evidence for benefits exists for preterm and low birth weight infants in neonatal intensive care settings, with effects typically observed within weeks of supplementation.
How it works
B. infantis exerts its beneficial effects primarily by metabolizing human milk oligosaccharides (HMOs), which facilitates its colonization and persistence within the infant gut. This metabolic activity gives it a competitive advantage over other bacteria. It strengthens the intestinal barrier by upregulating the expression of tight junction proteins, such as claudin 4, occludin, and ZO-1. This action reduces intestinal permeability, thereby preventing the translocation of harmful bacteria and toxins from the gut lumen into the bloodstream. Furthermore, B. infantis competitively inhibits the growth of pathogenic bacteria by occupying ecological niches and producing various metabolites that suppress pathogen proliferation. It also interacts with host immune cells, which may contribute to the modulation of inflammatory responses, though the precise molecular targets and pathways involved require further elucidation.
Side effects
B. infantis is generally considered safe, particularly in neonatal populations, with high-quality randomized controlled trials reporting no serious adverse events. Mild gastrointestinal symptoms such as bloating or gas are rare but may occur. There are no significant drug interactions or contraindications documented in the literature for B. infantis. While specific contraindications are not established, caution is advised for special populations such as immunocompromised infants, though no specific risks have been identified. The overall safety profile is excellent, supporting its use in vulnerable populations like preterm infants. No specific warnings regarding overdose or long-term adverse effects have been noted within typical therapeutic ranges.
Dosage
Effective daily doses of B. infantis in clinical trials typically range from approximately 1 × 10^8 to 6 × 10^9 colony-forming units (CFU). Supplementation is usually administered orally, often mixed with breast milk or infant formula to ensure easy consumption by infants. The duration of supplementation in studies commonly extends until hospital discharge for preterm infants or for several weeks post-birth, depending on the clinical context and specific study protocols. There is no established maximum safe dose beyond the ranges used in clinical trials, as these doses have consistently demonstrated good tolerability and safety. It is important to note that the specific strain and formulation can influence efficacy, and adherence to product-specific guidelines is recommended.
FAQs
Is B. infantis safe for preterm infants?
Yes, multiple randomized controlled trials and meta-analyses have confirmed the safety and efficacy of B. infantis in preterm infants, particularly for reducing NEC incidence.
How quickly does B. infantis work?
Colonization and clinical benefits, such as reduced NEC incidence, typically become apparent within 1 to 4 weeks of consistent supplementation in infants.
Can B. infantis be used with antibiotics?
While B. infantis can be used with antibiotics, antibiotics may reduce probiotic colonization. It is often recommended to time probiotic administration a few hours apart from antibiotic doses.
Is strain specificity important for B. infantis?
Yes, strain specificity is crucial. Different B. infantis strains can vary in their ability to utilize HMOs and colonize the gut, which directly impacts their efficacy and specific benefits.
Research Sources
- https://pubmed.ncbi.nlm.nih.gov/37460707/ – This systematic review and meta-analysis of over 20 RCTs involving preterm infants found that B. infantis supplementation significantly reduces the incidence of necrotizing enterocolitis (NEC) by 30-50% and improves gut barrier function. The study concluded that B. infantis is safe and effective in this vulnerable population, highlighting its role in preventing a severe neonatal condition.
- https://www.nature.com/articles/pr2014156 – This review and mechanistic study demonstrated that B. infantis exhibits competitive colonization in the infant gut, primarily due to its unique ability to metabolize human milk oligosaccharides (HMOs). It also detailed how B. infantis enhances gut barrier integrity by upregulating tight junction proteins, providing a strong mechanistic basis for its clinical benefits.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC10665187/ – This study, while not specifically on Bi45, provides context on effective probiotic dosing ranges in clinical trials, indicating that doses from 1 × 10^8 to 6 × 10^9 CFU daily are commonly used and well-tolerated. It supports the general dosage guidelines for B. infantis supplementation.
- https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2025.1585504/full – This RCT, though on a different B. infantis strain (YLGB-1496) and with a small sample size, showed that supplementation increased B. infantis abundance and improved microbiota composition in children. It supports the general concept of B. infantis's ability to positively modulate gut microbiota, even if not directly applicable to Bi45.
Supplements Containing Bifidobacterium Infantis Bi45
Recommended Articles
Top Ingredients for Optimal Gut Health
Fiber, probiotics, prebiotics, hydration, and fermented foods are crucial for maintaining healthy digestion and gut function.
Best Probiotic Strains & CFU for Health
Certain probiotic strains like Lactobacillus and Bifidobacterium, with CFU counts ranging from 1 billion for general wellness to 100 billion for conditions like IBS, are most beneficial.
Best Probiotic Strains for Your Health Goals
Certain probiotic strains offer targeted benefits for digestive health, immune support, weight management, and mental health.
Probiotics for IBS: Efficacy and Safety Insights
Probiotics significantly improve IBS symptoms and quality of life, with efficacy depending on the strain.