How does Lactobacillus rhamnosus support the immune system?
Lactobacillus rhamnosus, a widely studied probiotic, supports our immune system through a variety of complex and synergistic mechanisms.
In general, Lactobacillus rhamnosus exerts its effects primarily through three core pathways: "training" the immune system, strengthening the physical barrier, and regulating the immune response. Let's break down these mechanisms in detail:
1. Strengthening the Intestinal Barrier: "Building a Fortified Defense" The gut is the largest immune organ in the human body, and the intestinal mucosal barrier is the first line of defense against harmful substances and pathogens entering the body. Lactobacillus rhamnosus helps strengthen this defense.
Promoting Mucus Secretion: They can stimulate intestinal goblet cells to produce more mucin, forming a thick layer of mucus. This mucus effectively isolates bacteria and harmful substances, preventing them from directly contacting intestinal epithelial cells.
Enhancing Intercellular Connections: They help "tighten" the connections between intestinal epithelial cells (called "tight junctions"), like reinforcing the brickwork of a city wall, reducing intestinal permeability, preventing "leakage," and making it difficult for harmful substances to enter the bloodstream.
2. Direct Communication with the Immune System: "Education" and "Regulation" The gut is home to a large number of immune cells. *Lactobacillus rhamnosus* and its metabolites interact with these immune cells, "educating" and "regulating" them.
Regulating Immune Cell Balance:
Promoting Anti-inflammatory Factors: Lactobacillus rhamnosus stimulates immune cells (such as T cells) to produce more anti-inflammatory cytokines such as interleukin-10 (IL-10).
Inhibiting Pro-inflammatory Factors: Simultaneously, they reduce the production of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α).
This action helps regulate the immune state from an excessive "Th2 response" (associated with allergies) or excessive inflammation to a more balanced "Th1" state, thereby reducing unnecessary inflammation and allergic reactions.
Stimulating sIgA Production: They promote the production of secretory immunoglobulin A (sIgA) in the intestinal mucosa. sIgA is a major force in mucosal immunity. Like a "patrol policeman," it neutralizes invading viruses and bacteria, preventing them from attaching to the intestinal wall and clearing them out.
Training the innate immune system: Lactobacillus rhamnosus can gently "activate" the innate immune system by interacting with pattern recognition receptors (such as Toll-like receptors) on the surface of intestinal epithelial cells and immune cells. This continuous, low-level stimulation is like giving the immune system "daily rehearsals," keeping it alert but not overreacting, thus enabling a faster and more effective response when encountering real pathogens.
3. Competitive Rejection: "Occupying Space and Fighting for It"
This is a very direct support mechanism.
Occupying Space: Lactobacillus rhamnosus can better adhere to the intestinal wall, competing with harmful bacteria for "seats" (colonization sites). If good bacteria occupy all the spaces, bad bacteria have nowhere to settle and find it difficult to colonize and multiply in the intestine.
Competing for Nutrients: They also compete with harmful bacteria for nutrients, leaving bad bacteria "starved."
Creating an unfavorable environment: Substances such as lactic acid produced during their metabolism can lower the intestinal pH, creating an acidic environment unfavorable to the survival of many harmful bacteria.
4. Producing beneficial metabolites: "Providing ammunition" During fermentation, Lactobacillus rhamnosus produces substances crucial to the immune system.
Short-chain fatty acids (SCFAs): After fermenting dietary fiber, they produce short-chain fatty acids such as butyric acid, acetic acid, and propionic acid.
Butyric acid is a major energy source for intestinal epithelial cells and helps maintain the integrity of the intestinal barrier.
SCFAs also have direct anti-inflammatory effects and can help regulate the function of Treg cells (regulatory T cells), which are "peacemakers" that suppress excessive immune responses and maintain immune tolerance.
Major immune benefits confirmed by scientific research: Based on the above mechanisms, clinical studies have discovered the following specific immune benefits of Lactobacillus rhamnosus (especially certain strains, such as LGG):
Prevention and reduction of respiratory infections: Multiple studies have shown that regular supplementation with Lactobacillus rhamnosus can reduce the incidence of respiratory infections such as colds and influenza in children and adults, shorten the course of illness, and alleviate symptoms.
Reducing the risk of antibiotic-associated diarrhea: During antibiotic use, antibiotics indiscriminately kill both good and bad bacteria in the gut, leading to gut microbiota imbalance. Supplementation with Lactobacillus rhamnosus can help maintain gut microbiota balance and significantly reduce the probability of diarrhea.
Improving and preventing atopic dermatitis (eczema): Early supplementation with Lactobacillus rhamnosus has been shown to significantly reduce the risk of eczema in infants and young children at high risk of allergies (e.g., parents with a history of allergies).
Helping to improve certain intestinal inflammations: For some functional bowel problems, it also helps regulate bowel function and relieve discomfort.
In summary, Lactobacillus rhamnosus supports the immune system not as a single action, but as a multi-pronged, synergistic system. It does so through:
Building a wall (strengthening the intestinal barrier)
Training (training and regulating immune cells)
Occupying space (competitively rejecting pathogens)
Providing nourishment (producing beneficial metabolites)
These mechanisms work together to ultimately balance the immune response, enhance defense capabilities, and suppress excessive inflammation, thus comprehensively supporting the health of our immune system.