What is the Function of Lactobacillus salivarius?

Naturally found in the oral cavity, intestines, and vaginal tract, Lactobacillus salivarius is a key probiotic known for its diverse and powerful functional properties. This lactic acid bacterium contributes to a healthy microbiome balance in several locations within the human body by crowding out harmful microbes and producing beneficial compounds.

Quick Summary

Lactobacillus salivarius is a probiotic that produces antimicrobial substances, adheres to mucosal surfaces, and modulates immune responses to support digestive, oral, and overall health.

Key Points

• Antimicrobial Action: Lactobacillus salivarius produces bacteriocins, lactic acid, and hydrogen peroxide to inhibit a wide range of pathogenic bacteria and fungi in the gut, mouth, and vagina.

• Oral Health Support: It helps maintain a healthy oral microbiome by outcompeting harmful bacteria like Streptococcus mutans, reducing plaque, gum inflammation, and bad breath.

• Gut Barrier Enhancement: This probiotic reinforces the integrity of the intestinal mucosal barrier, which is crucial for preventing systemic inflammation and managing gastrointestinal conditions.

• Immune System Modulation: L. salivarius interacts with the gut's immune tissue to balance cytokine production, exhibiting anti-inflammatory effects that can benefit conditions like atopic dermatitis.

• Metabolic Support: The bacterium's fermentative activities assist in digestion and the production of beneficial metabolites like short-chain fatty acids.

• Microbiome Balance: Its ability to adhere to mucosal surfaces and compete for resources helps establish and maintain a stable, healthy microbial balance in various parts of the body.

• Vaginal Flora Regulation: In the vaginal tract, it contributes to a healthy, acidic environment that inhibits the growth of pathogens associated with infections.

Overview of Lactobacillus salivarius

Lactobacillus salivarius is a species of probiotic bacteria and a natural inhabitant of the human body, specifically found in the mouth, gastrointestinal tract, and vagina. As a member of the lactic acid bacteria family, it creates a slightly acidic environment that is inhospitable to many pathogenic organisms. This versatile probiotic was historically part of the Lactobacillus genus but was reclassified as Ligilactobacillus salivarius in 2020, although many product labels still use the former name. Its fast-growing nature and ability to thrive in mucosal environments make it a significant contributor to host health. The functions of L. salivarius are highly strain-specific, meaning that different strains may have unique properties and target different health areas.

Key Functions of Lactobacillus salivarius

Antimicrobial Activity

One of the most defining functions of L. salivarius is its robust antimicrobial action against a wide range of harmful bacteria and fungi. It employs several mechanisms to achieve this:

• Production of bacteriocins: Many strains of L. salivarius produce small, potent antimicrobial peptides known as bacteriocins. These compounds can directly inhibit or kill competing bacteria by disrupting their cell membranes, providing a competitive advantage within its environment. The bacteriocin Abp118, produced by strain UCC118, is a well-studied example that effectively combats pathogens like Listeria monocytogenes.
• Production of organic acids: By fermenting carbohydrates, L. salivarius generates lactic and acetic acids. These acids lower the local pH, creating an acidic environment that is difficult for many pathogens, including Helicobacter pylori, to survive and thrive in.
• Production of hydrogen peroxide: Certain strains produce hydrogen peroxide (H2O2), an oxidizing agent with antimicrobial properties, further suppressing the growth of harmful bacteria in specific mucosal environments, such as the vagina.
• Competitive exclusion: By adhering to mucosal surfaces in the mouth, gut, and vagina, L. salivarius outcompetes pathogens for adhesion sites and nutrients, physically blocking their colonization.

Modulation of the Gut Microbiome

Lactobacillus salivarius plays a fundamental role in maintaining a balanced and healthy gut ecosystem through several key functions:

• Microbiota regulation: It helps shape the composition of the intestinal microbiota by inhibiting the proliferation of pathogenic species, allowing beneficial bacteria to flourish.
• Enhanced gut barrier function: Research indicates that some strains can help reinforce the intestinal barrier, a critical function for preventing harmful substances from entering the bloodstream. This protective effect is particularly relevant in conditions like diabetes-induced intestinal impairment.
• Anti-inflammatory effects: Some strains have been shown to modulate immune responses in the gut, reducing inflammation. This has been studied in contexts related to inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS).
• Digestive aid: Through its fermentative activities, L. salivarius can assist in breaking down carbohydrates and potentially aid protein digestion, contributing to digestive comfort and nutrient availability.

Support for Oral Health

Its presence in the oral cavity gives L. salivarius a special function in oral hygiene and disease prevention:

• Combats cariogenic bacteria: Specific strains can inhibit the growth of bacteria associated with dental caries, such as Streptococcus mutans, helping to reduce the risk of tooth decay.
• Reduces gingival inflammation: Clinical trials have demonstrated that certain strains can improve measures of gum health, including reduced plaque index and inflammation, potentially benefiting individuals with gingivitis or periodontitis.
• Reduces oral malodor: By influencing the microbial balance in the mouth, L. salivarius can help reduce bad breath associated with certain odor-producing bacteria.

Immune System Regulation

In addition to its direct antimicrobial functions, L. salivarius interacts with the host immune system:

• Balancing cytokine production: It can help balance the production of cytokines, which are signaling molecules of the immune system. For example, some strains have been shown to increase anti-inflammatory cytokines like IL-10 while suppressing pro-inflammatory ones.
• Allergy and eczema support: Some preliminary studies have investigated strains like LS01 for their potential to reduce symptoms and improve the quality of life for children with atopic dermatitis.

Contribution to Vaginal Health

For females, L. salivarius contributes to maintaining a healthy vaginal microbiome:

• Inhibits pathogens: By producing lactic acid and other antimicrobial substances, it helps create an acidic environment that inhibits the growth of pathogens associated with bacterial vaginosis (Gardnerella vaginalis) and yeast infections (Candida).
• Balances vaginal flora: It plays a role in restoring the balance of vaginal flora, especially after antibiotic use, and has shown promise in managing recurrent vaginal infections.

Comparing Lactobacillus salivarius with Other Probiotics

Feature	Lactobacillus salivarius	Lactobacillus rhamnosus GG	Lactobacillus crispatus
Primary Function	Versatile, active in oral cavity, gut, and vagina.	Well-researched for gut health and immune support.	Key species for vaginal health, produces copious lactic acid.
Key Mechanisms	Produces bacteriocins, lactic acid, H2O2; strong mucosal adhesion.	Adheres well to mucus, produces specific pili structures, secretes active proteins.	Produces lactic acid and H2O2; adheres to vaginal epithelial cells.
Specific Targets	Oral pathogens (S. mutans, bad breath), gut pathogens (H. pylori), vaginal pathogens (Candida).	Various gastrointestinal pathogens, immune modulatory pathways.	Vaginal pathogens (G. vaginalis, Candida), important for vaginal pH.
Main Location(s)	Oral cavity, intestines, vaginal tract.	Gastrointestinal tract.	Vaginal tract.
Evidence Level	Strong evidence for oral and gut colonization; moderate clinical evidence for specific health outcomes.	Extensive and robust clinical evidence, especially for diarrhea and eczema.	Well-established for vaginal health; primary vaginal colonizer.

Sources of Lactobacillus salivarius

While some fermented foods may contain Lactobacillus species, the presence of specific strains of L. salivarius is generally not guaranteed unless explicitly added. Therefore, the most reliable way to obtain a targeted strain is through dietary supplements. Probiotic formulas, often in capsules or tablets, can contain specific, well-researched strains of L. salivarius. Consuming a diet rich in prebiotic fibers, found in foods like chicory root, garlic, and onions, can also support the growth of native beneficial bacteria.

Conclusion

Lactobacillus salivarius is a highly functional and versatile probiotic bacterium with a wide array of roles across the human body. Its primary functions involve robust antimicrobial action, effective modulation of the gut and oral microbiomes, and immune system regulation. It actively competes with pathogens, produces beneficial metabolic byproducts, and strengthens mucosal barriers. The specific health benefits can vary between different strains, highlighting the importance of looking for clinically studied strains when choosing a probiotic supplement. With growing research confirming its benefits for digestive, oral, and vaginal health, L. salivarius remains a key player in probiotic science. For more detailed clinical studies, including those on specific strains, you can refer to academic sources like PubMed.

Frequently Asked Questions

What kind of bacteria is *Lactobacillus salivarius*?

Lactobacillus salivarius is a species of lactic acid bacteria that is considered a probiotic, meaning it provides health benefits when consumed.

Where is *Lactobacillus salivarius* found in the human body?

It is naturally found in several areas, including the oral cavity, the gastrointestinal tract (stomach and intestines), and the female vaginal tract.

How does *Lactobacillus salivarius* support oral health?

It supports oral health by producing antimicrobial compounds, outcompeting bacteria that cause dental caries and gum disease, and helping to reduce plaque and bad breath.

Can I get *Lactobacillus salivarius* from yogurt or other fermented foods?

While many fermented foods contain Lactobacillus species, most commercial yogurts use standard starter cultures and may not contain L. salivarius unless specifically added. Supplements are the most reliable source for specific strains.

Does *Lactobacillus salivarius* help with digestion?

Yes, it contributes to digestive comfort by assisting with carbohydrate fermentation and helping to maintain a balanced and healthy gut microbiome.

Is *Lactobacillus salivarius* good for the immune system?

It modulates the immune system, particularly within the gut-associated lymphoid tissue, helping to balance inflammatory responses and potentially benefiting immune-related conditions.

Is *Lactobacillus salivarius* the same as *Ligilactobacillus salivarius*?

Yes, Ligilactobacillus salivarius is the new taxonomic name for the species, following a 2020 reclassification. Many products and studies, however, still use the original name.