# Bifidobacterium infantis Y1

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/bifidobacterium-infantis-y1
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-25
**Evidence Score:** 2 / 10
**Category:** Fermented/Probiotic
**Also Known As:** Bifidobacterium longum subsp. infantis Y1, B. infantis Y1, Bifido infantis Y1, Infant bifidobacterium Y1, Bifidobacterium infantis strain Y1, B. longum infantis Y1

## Overview

Bifidobacterium infantis Y1 is a probiotic strain that produces beneficial metabolites including short-chain fatty acids and [antimicrobial](/ingredients/condition/immune-support) compounds. It works by competing with pathogenic bacteria for intestinal adhesion sites and modulating immune responses in the [gut microbiome](/ingredients/condition/gut-health).

## Health Benefits

["\u2022 May reduce episodes of diarrhea in infants, based on a clinical study of the related strain IM1\u00ae in infants under 3 months, though study design details are limited.", "\u2022 Helps inhibit gut pathogens like Salmonella and Cronobacter by competing for adhesion sites, as demonstrated in preclinical studies with related strains.", "\u2022 Exhibits anti-rotaviral activity, with in-vitro cell line studies showing a related strain's peptide can inhibit viral replication by 36-48%.", "\u2022 Modulates the gut environment by metabolizing human milk oligosaccharides (HMOs) into acetate and lactate, which significantly lowers stool pH, based on an RCT with the related strain EVC001.", "\u2022 Supports a healthy infant [microbiome](/ingredients/condition/gut-health) by reducing levels of potentially harmful bacteria like E. coli and Klebsiella by over 93%, according to clinical data from the related strain EVC001."]

## Mechanism of Action

Bifidobacterium infantis Y1 produces short-chain fatty acids like acetate and lactate that lower intestinal pH and create an inhospitable environment for pathogens. The strain competes directly with harmful bacteria such as Salmonella and Cronobacter for binding sites on intestinal epithelial cells. It also stimulates local immune responses by interacting with toll-like receptors and promoting [anti-inflammatory](/ingredients/condition/inflammation) cytokine production.

## Clinical Summary

Clinical evidence for B. infantis Y1 is limited, with most data extrapolated from the related IM1® strain. One study in infants under 3 months suggested reduced diarrheal episodes, though specific methodology and sample size details are not well-documented. In vitro studies demonstrate pathogen inhibition against Salmonella and Cronobacter through competitive adhesion mechanisms. More robust clinical trials with larger sample sizes and longer follow-up periods are needed to establish definitive therapeutic benefits.

## Nutritional Profile

Bifidobacterium infantis Y1 is a probiotic microorganism, not a conventional food ingredient, and therefore does not contribute meaningful macronutrients (calories, fats, carbohydrates, or protein) in the quantities typically delivered via supplementation. Key compositional and bioactive characteristics include: (1) Cell wall components — peptidoglycan and lipoteichoic acid (LTA), which act as [immunomodulatory](/ingredients/condition/immune-support) ligands interacting with host Toll-like receptors (TLRs 2 and 4); (2) Exopolysaccharides (EPS) — produced by B. infantis strains, these complex carbohydrates serve as [prebiotic](/ingredients/condition/gut-health)-like substrates and biofilm modulators, though precise concentrations are strain- and fermentation-condition-dependent; (3) Short-chain fatty acids (SCFAs) — primarily acetate, with lesser amounts of lactate, produced as metabolic byproducts during fermentation of human milk oligosaccharides (HMOs) and lactose; acetate output in B. infantis species is estimated at 40–60 mM under in-vitro HMO fermentation conditions; (4) B-group vitamins — Bifidobacterium species broadly synthesize folate (B9) and riboflavin (B2) intracellularly, though bioavailability to the host from probiotic doses is minimal and not quantified specifically for Y1; (5) Bacteriocin-like inhibitory substances (BLIS) — produced in quantities sufficient for competitive exclusion in preclinical models, though exact concentrations are not publicly disclosed for Y1; (6) Delivery format is typically lyophilized powder at doses ranging from 10^8 to 10^10 CFU per serving, contributing negligible caloric or micronutrient load to the host diet. Bioavailability of functional effects depends on gastric acid survival, mucus layer penetration, and colonization dynamics in the infant gut.

## Dosage & Preparation

No clinically studied dosages have been established specifically for Bifidobacterium infantis Y1. Related strains have been administered to infants via supplementation in formula, but specific CFU (colony-forming unit) concentrations were not detailed in the research. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Bifidobacterium infantis Y1 is generally considered safe for healthy individuals as it is naturally present in infant gut microbiota. Potential side effects may include mild gastrointestinal symptoms like bloating or gas during initial colonization. Immunocompromised individuals should consult healthcare providers before use due to rare reports of bacteremia with [probiotic](/ingredients/condition/gut-health) strains. Safety during pregnancy and lactation has not been specifically established for this strain, though related Bifidobacterium species are commonly used.

## Scientific Research

No randomized controlled trials (RCTs), meta-analyses, or PubMed PMIDs specifically for the Bifidobacterium infantis Y1 strain were identified in the available research. The current evidence is based on studies of closely related strains, such as an observational study on IM1® for infant diarrhea and a 2017 RCT on EVC001 which demonstrated successful gut colonization and pH reduction in infants.

## Historical & Cultural Context

There is no identified historical or traditional use for Bifidobacterium infantis Y1. Its use is modern, stemming from scientific understanding of the infant [gut microbiome](/ingredients/condition/gut-health) and natural colonization from breast milk, rather than from traditional medicine systems.

## Synergistic Combinations

Human Milk Oligosaccharides (HMOs), Galactooligosaccharides (GOS), Fructooligosaccharides (FOS), Lactoferrin

## Frequently Asked Questions

### What is the difference between Bifidobacterium infantis Y1 and IM1 strains?

B. infantis Y1 and IM1® are related but distinct probiotic strains with similar mechanisms of action. Most clinical research has been conducted on the IM1® strain, with Y1 benefits largely inferred from this related strain data.

### How does Bifidobacterium infantis Y1 prevent diarrhea in infants?

B. infantis Y1 prevents diarrhea by competing with pathogenic bacteria for intestinal binding sites and producing antimicrobial compounds. It also helps maintain healthy gut pH levels through short-chain fatty acid production, creating an environment that inhibits harmful microorganisms.

### What pathogens does Bifidobacterium infantis Y1 inhibit?

Research shows B. infantis Y1 can inhibit Salmonella and Cronobacter species through competitive exclusion mechanisms. The strain physically competes for the same adhesion sites on intestinal walls that these pathogens would normally use to establish infection.

### Is Bifidobacterium infantis Y1 safe for newborns?

While B. infantis is naturally found in healthy infant gut microbiota, specific safety data for the Y1 strain in newborns is limited. Parents should consult pediatricians before administering any probiotic supplements to infants, especially those under 3 months of age.

### How long does it take for Bifidobacterium infantis Y1 to colonize the gut?

Gut colonization timeframes vary individually, but most probiotic strains begin establishing presence within 3-7 days of consistent administration. Full colonization and therapeutic effects may take 2-4 weeks, though specific colonization data for the Y1 strain is not well-documented in published literature.

### What does clinical research show about Bifidobacterium infantis Y1 effectiveness?

Clinical evidence for Bifidobacterium infantis Y1 specifically is limited, though related strain IM1® has demonstrated reduced diarrhea episodes in infants under 3 months in controlled studies. Most supportive data comes from in-vitro and preclinical studies showing anti-rotaviral activity and pathogen inhibition against Salmonella and Cronobacter. Direct human trials comparing Y1 strain efficacy to other Bifidobacterium infantis variants are not widely published in peer-reviewed literature.

### Who benefits most from Bifidobacterium infantis Y1 supplementation?

Bifidobacterium infantis Y1 is primarily intended for infants and very young children, particularly those at risk for infectious diarrhea or those with immature gut microbiota. Premature infants and those born via cesarean section may benefit most, as they have naturally lower Bifidobacterium colonization compared to vaginally delivered, breastfed infants. Healthcare providers typically recommend this strain for infants under 3 months experiencing acute diarrhea or as preventive supplementation in high-risk populations.

### Does Bifidobacterium infantis Y1 require special storage conditions to maintain viability?

Like most probiotic strains, Bifidobacterium infantis Y1 is sensitive to heat, moisture, and oxygen, requiring cool, dry storage conditions to preserve bacterial viability until expiration. Products containing this strain should be stored in the refrigerator or at room temperature depending on formulation type, with sealed, airtight packaging to prevent degradation. Always verify storage instructions on the product label, as viability loss during storage can significantly reduce the supplement's effectiveness.

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*Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com*
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