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Streptococcus Salivarius

Also known as: Streptococcus salivarius, Probiotic strain K12, M18, 24SMB

Overview

Streptococcus salivarius is a gram-positive, commensal bacterium that naturally colonizes the human oral cavity and upper respiratory tract. It is commonly used as an oral probiotic, and to a lesser extent, as a gastrointestinal probiotic. Primary applications include reducing halitosis, managing oral biofilms, and modulating the immune system. While research on S. salivarius has increased since 2010, large-scale trials remain limited. It can be sourced from the human oral microbiome and, rarely, from fermented dairy products. The evidence quality is considered moderate, with systematic reviews available but limited long-term data. S. salivarius is available in various forms, including lyophilized powders and lozenges, designed to promote oral colonization.

Benefits

Streptococcus salivarius offers several evidence-based benefits, particularly for oral health. It has been shown to reduce halitosis by decreasing volatile sulfur compounds (VSC), with short-term studies showing significant reductions. Organoleptic breath scores also improve with longer-term use. The M18 strain specifically reduces gingival bleeding and biofilm accumulation after three months of use. Furthermore, S. salivarius, particularly the K12 strain, supports the immune system by increasing salivary secretory IgA (sIgA) secretion post-supplementation. These benefits are supported by systematic reviews and clinical trials, though more extensive long-term data is needed to solidify these findings.

How it works

Streptococcus salivarius exerts its beneficial effects through several mechanisms. It inhibits pathogenic bacteria, such as Streptococcus pyogenes, via the production of bacteriocins, leading to competitive exclusion. Additionally, it enhances mucosal immunity by upregulating sIgA secretion, which is crucial for immune defense in the oral cavity. S. salivarius also disrupts biofilm formation by reducing the adhesion of plaque-forming bacteria, contributing to improved oral hygiene. These actions collectively help maintain a healthy oral microbiome and support immune function.

Side effects

Streptococcus salivarius is generally recognized as safe (GRAS) with a low incidence of side effects. The most commonly reported side effect is mild gastrointestinal discomfort, occurring in less than 1% of users. However, caution is advised for immunocompromised individuals due to a theoretical risk of opportunistic infection. No drug interactions have been documented. It is important to note that while S. salivarius is considered safe for most people, individuals with compromised immune systems should consult with a healthcare provider before use. Overall, S. salivarius has a favorable safety profile when used as directed.

Dosage

The effective dosage of Streptococcus salivarius, particularly K12 and M18 strains, typically ranges from 1 to 2 billion CFU per day. For immune effects, a minimum duration of 30 days is recommended, while oral health benefits may require at least three months of consistent use. It is available in lyophilized powders or lozenges, which are designed to promote oral colonization. Timing considerations are not critical, but consistent daily intake is advisable. While specific upper limits are not well-defined, exceeding the recommended dosage is unlikely to provide additional benefits and may increase the risk of mild gastrointestinal discomfort.

FAQs

How quickly does it work for bad breath?

Volatile sulfur compound (VSC) reduction can be observed within 2–4 weeks, with full effects typically noticeable by 3 months of consistent use.

Can it replace mouthwash?

No, it should be used as an adjunctive treatment. It lacks the immediate antimicrobial effects of mouthwash but provides longer-term benefits for oral microbiome balance.

Is refrigeration required?

This is strain-dependent. However, most commercial products are formulated to be shelf-stable, but checking the product label for storage instructions is always recommended.

Research Sources

https://bmjopen.bmj.com/content/12/12/e060753 – This systematic review evaluated the use of Streptococcus salivarius for pediatric prophylaxis. The findings suggest that it is a cost-effective intervention for reducing the incidence of streptococcal pharyngitis in children. However, the review also notes that outcomes can vary depending on the specific strain used, highlighting the need for strain-specific research.
https://pubmed.ncbi.nlm.nih.gov/36600415/ – This meta-analysis, encompassing eight randomized controlled trials with a total of 312 participants, investigated the efficacy of probiotics for halitosis. The results indicated that probiotics are significantly more effective than placebo in reducing halitosis. A limitation of this study is the short follow-up period, which was limited to three months or less.
https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2023.1129060/full – This double-blind, placebo-controlled RCT (n=20) examined the impact of the K12 strain on immune function. The study found that K12 supplementation led to a significant increase in salivary secretory IgA (sIgA) secretion following exercise. The study's limitations include its small sample size and single-center design, which may limit the generalizability of the findings.
https://www.mdpi.com/2304-6767/12/7/222 – This 3-month RCT (n=30) assessed the effects of the M18 strain on oral health. The study demonstrated that M18 supplementation resulted in a significant reduction in gingival bleeding. However, the study did not include a microbiome analysis, which could have provided further insights into the mechanisms of action.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11676405/ – This article discusses the role of oral bacteria in health and disease. It highlights the importance of maintaining a balanced oral microbiome and the potential of probiotics like Streptococcus salivarius to promote oral health by inhibiting the growth of pathogenic bacteria and modulating the immune response.