Bacterial Lipopolysaccharide

Definition

Lipopolysaccharide (LPS) is an endotoxin component of gram-negative bacterial outer membranes. When released in excessive amounts, LPS triggers immune responses and can increase intestinal permeability through zonulin activation.

How it works

LPS is a complex molecule found on the surface of gram-negative bacteria, including common species in the gut microbiome. Under normal conditions, the intestinal barrier prevents significant LPS translocation. However, when dysbiosis occurs—an imbalance in microbial communities favoring gram-negative species—or when intestinal permeability increases, LPS can enter the bloodstream. There, it binds to toll-like receptors on immune cells, triggering a cascade of inflammatory responses. LPS also stimulates zonulin release, creating a feedback loop that further damages the intestinal barrier.

Role

Activates innate immune responses and can compromise intestinal barrier function through zonulin-mediated tight junction disruption.

Examples

• LPS from dysbiotic E. coli
• gram-negative pathogenic bacteria proliferation
• endotoxin from Vibrio species
• lipid A component triggering TLR4 activation

Recommendations

Reduce LPS translocation by maintaining a healthy microbiome through adequate fiber intake and probiotic foods. Limit conditions that promote gram-negative bacterial overgrowth, such as high sugar consumption and antibiotic overuse. Support barrier function with anti-inflammatory foods rich in omega-3 fatty acids and polyphenols.

Key takeaway

Controlling LPS levels through microbiome balance is critical for preventing metabolic endotoxemia and systemic inflammation.

Related terms