Probiotics (Multi-Strain) — Live microorganisms / gut microbiome modulator

Probiotics are live bacteria and yeasts that, when administered in adequate amounts, confer a health benefit on the host (WHO/FAO definition). Mechanisms: (1) Competitive exclusion of pathogens; (2) Production of bacteriocins, SCFAs (short-chain fatty acids), and lactic acid; (3) Fortification of gut barrier (tight junction proteins ZO-1, claudin); (4) Immune modulation via Toll-like receptors and dendritic cells — increases Tregs, reduces inflammatory cytokines; (5) Gut-brain axis signaling via vagus nerve and neurotransmitter production (GABA, serotonin). Multi-strain formulations generally outperform single-strain for most indications.

Overview

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Compound Class

Live microorganisms / gut microbiome modulator

Mechanism of Action

Probiotics are live bacteria and yeasts that, when administered in adequate amounts, confer a health benefit on the host (WHO/FAO definition). Mechanisms: (1) Competitive exclusion of pathogens; (2) Production of bacteriocins, SCFAs (short-chain fatty acids), and lactic acid; (3) Fortification of gut barrier (tight junction proteins ZO-1, claudin); (4) Immune modulation via Toll-like receptors and dendritic cells — increases Tregs, reduces inflammatory cytokines; (5) Gut-brain axis signaling via vagus nerve and neurotransmitter production (GABA, serotonin). Multi-strain formulations generally outperform single-strain for most indications.

Regulatory Status

OTC dietary supplement. Some strains are OTC drugs (Saccharomyces boulardii — VSL#3 is FDA-regulated medical food). Regulatory framework evolving.

Evidence Level

Moderate-High (indication-specific). Cochrane meta-analysis: Lactobacillus/Saccharomyces for AAD (RR 0.46). IBS evidence mixed but positive for functional bloating/pain. AGA and WGO guidelines support specific strain-indication combinations.