Bifidobacterium longum W11

About

What it is and where it shows up.

Bifidobacterium longum W11 (deposited as LMG P-21586) is a probiotic bacterial strain originally isolated from the intestinal microbiota of a healthy adult. It is used as a functional food and dietary supplement ingredient for the management of gut dysbiosis, irritable bowel syndrome (IBS), and inflammatory bowel disease, and is uniquely characterised by a non-transmissible rifaximin resistance enabling co-administration with that antibiotic.

Safety summary

The regulatory and scientific consensus.

Bifidobacterium longum as a species is considered nonpathogenic to healthy humans, with rare adverse events limited almost exclusively to severely immunocompromised individuals. EFSA has granted the species Qualified Presumption of Safety (QPS) status, reflecting a broad regulatory consensus on its safety. No formal ADI has been established; typical probiotic doses range from 10^8 to 10^10 CFU/day and have been well tolerated in clinical trials.

Regulatory landscape

What food-safety regulators have decided.

Jurisdiction	Status	Note
EFSA (European Food Safety Authority) (European Union)	Approved	B. longum holds Qualified Presumption of Safety (QPS) status from EFSA, meaning strains of this species are presumed safe for use in food and feed without case-by-case risk assessment, provided acquired antimicrobial resistance is absent. The strain W11 was submitted for Article 13 health claim evaluation (EFSA ID 3056) but no specific health claim was authorised at the species/strain level.source
FSSAI (Food Safety and Standards Authority of India) (India)	Approved	FSSAI recognises Bifidobacterium longum as an acceptable probiotic species for use in health supplements, nutraceuticals, and foods for special medical purposes. No W11 strain-specific restriction identified.source
FDA (Food and Drug Administration) (United States)	Approved	B. longum as a species is grandfathered as an ingredient in dietary supplements under DSHEA. Multiple other B. longum strains have received FDA GRAS status (e.g., GRN 813, GRN 1079). No W11-specific GRAS notice has been identified; the species-level safety framework applies.source

Who should approach with care

Whose guidance would steer them away.

Other — Immunocompromised individuals (e.g., those on immunosuppressants, with HIV/AIDS, or with severe underlying illness) should consult a doctor before use, as rare cases of Bifidobacterium bacteraemia have been reported almost exclusively in this population.

Ibs — While B. longum W11 has been studied specifically for IBS-constipation with positive results, IBS management is highly individual; patients should consult a healthcare provider to confirm appropriateness of use.

Ibd — Clinical use in inflammatory bowel disease has been reported, but probiotic use during IBD flares should be supervised by a gastroenterologist.

Research citations

The sources behind this verdict.

1EFSA. Qualified Presumption of Safety (QPS) — Bifidobacterium longum species assessment. efsa.europa.eu
2PubMed. The Anti-Constipation Effect of Bifidobacterium Longum W11 Is Likely Due to a Key Genetic Factor Governing Arabinan Utilization, 2024. pubmed.ncbi.nlm.nih.gov
3PubMed. Bifidobacterium longum W11: Uniqueness and individual or combined clinical use in association with rifaximin, 2021. pubmed.ncbi.nlm.nih.gov
4PubMed. Immunomodulatory Effects of Bifidobacterium longum W11 Produced Exopolysaccharide on Cytokine Production, 2018. pubmed.ncbi.nlm.nih.gov
5PubMed. Complete Genome Sequence of Bifidobacterium longum W11 (LMG P-21586), Used as a Probiotic Strain, 2017. pubmed.ncbi.nlm.nih.gov

Independently researched5 citations