Streptococcus salivarius M18
Also known as: S. salivarius M18, probiotic strain M18, Streptococcus salivarius M18
Overview
Streptococcus salivarius M18 is a specific strain of probiotic bacteria naturally found in the human oral cavity. It is utilized as a dietary supplement primarily to support and improve oral health. This probiotic works by colonizing the oral microbiome and producing beneficial compounds, such as bacteriocins, which help inhibit the growth of harmful bacteria responsible for common oral issues. Its main applications include reducing halitosis (bad breath), decreasing gingival inflammation, and minimizing dental plaque accumulation. Research on S. salivarius M18 is ongoing, with several randomized controlled trials (RCTs) and systematic reviews indicating positive effects, particularly for halitosis and gum health. While the evidence is generally favorable, some studies are limited by sample size or duration. It is considered a moderate-maturity research area with growing support for its efficacy as an oral health probiotic.
Benefits
Streptococcus salivarius M18 offers several evidence-based benefits for oral health. It significantly reduces halitosis, showing a decrease in organoleptic scores and volatile sulfur compound levels, particularly in the short term (within 4 weeks). For gingival health, studies indicate a significant decrease in gingival bleeding, with improvements observed at 1, 2, and 3 months. It also contributes to a significant reduction in dental plaque accumulation, with effects noted around 2 months. While some evidence suggests improvements in tongue coating and plaque index, these are not consistently significant across all studies. The benefits are observed in both children and adults, with the most robust evidence in individuals already experiencing oral health issues. The effect sizes for halitosis and gingival health are moderate, suggesting clinically meaningful but not transformative improvements. Benefits for halitosis appear within weeks, while improvements in gum health and plaque are sustained over several months.
How it works
Streptococcus salivarius M18 primarily exerts its beneficial effects by acting locally within the oral cavity. Its key mechanism involves the production of bacteriocins, such as salivaricin, which are antimicrobial peptides. These bacteriocins specifically inhibit the growth of common oral pathogens, including *Streptococcus mutans*, a primary contributor to dental caries, and *Porphyromonas gingivalis*, a bacterium associated with periodontal disease. By outcompeting and suppressing these harmful bacteria, S. salivarius M18 helps to rebalance and maintain a healthy oral microbiome. It does not undergo systemic absorption, meaning its action is confined to the mouth, directly modulating the bacterial population and reducing the pathogenic load responsible for issues like bad breath, gum inflammation, and plaque formation.
Side effects
Streptococcus salivarius M18 is generally considered safe for oral use, with a favorable safety profile. Clinical trials have not reported any common side effects (occurring in more than 5% of users). Uncommon side effects (1–5%) are rare and typically mild, occasionally including slight oral discomfort or minor taste changes. Serious adverse events have not been reported in studies. There are no known significant drug interactions with S. salivarius M18. As with all probiotic supplements, caution is advised for individuals who are severely immunocompromised, although no specific contraindications have been established. It is considered safe for use in both children and healthy adults. However, there is currently insufficient data regarding its safety for pregnant or breastfeeding women, so use in these populations should be approached with caution and under medical guidance.
Dosage
The optimal dosage for Streptococcus salivarius M18 is typically within the range of 1 to 2 billion Colony Forming Units (CFU) per day. While a minimum effective dose is not definitively established, most clinical studies demonstrating benefits have utilized dosages within this range. Doses up to 2 billion CFU/day have been safely administered without reported adverse effects, and a maximum safe dose has not been determined. For best results, S. salivarius M18 supplements, commonly available as lozenges or tablets, should be taken once daily. It is generally recommended to use the supplement after performing oral hygiene practices such as brushing and flossing, to allow for optimal colonization of the oral cavity. Since S. salivarius M18 acts locally in the mouth and is not absorbed systemically, factors related to absorption and bioavailability are not relevant. No specific cofactors are required for its efficacy.
FAQs
How should I take S. salivarius M18 for the best results?
For optimal colonization and effectiveness, S. salivarius M18 lozenges or tablets should be taken once daily, preferably after you have brushed and flossed your teeth.
How long does it take to see benefits from S. salivarius M18?
Benefits for halitosis can be observed within 4 weeks. Improvements in gingival health and plaque reduction typically become noticeable and sustained over 1 to 3 months of consistent use.
Is S. salivarius M18 a substitute for regular dental hygiene?
No, S. salivarius M18 is not a substitute for brushing, flossing, or professional dental care. It should be used as an adjunct to a comprehensive oral hygiene routine to enhance oral health.
Are there any serious side effects associated with S. salivarius M18?
S. salivarius M18 is generally considered safe. Clinical trials have reported no serious adverse events, and common side effects are rare and mild, such as slight oral discomfort.
Can children use S. salivarius M18?
Yes, S. salivarius M18 has been studied in children and is considered safe for use in this population to support oral health, particularly for issues like dental plaque and gingivitis.
Research Sources
- https://bmjopen.bmj.com/content/12/12/e060753 – This meta-analysis of randomized controlled trials investigated the efficacy of S. salivarius M18 in reducing halitosis. It found a significant reduction in both organoleptic scores and volatile sulfur compound levels in the short term, with organoleptic scores remaining significant long-term. The study highlighted the need for more high-quality research despite positive findings.
- https://pubmed.ncbi.nlm.nih.gov/23449874/ – This randomized double-blind, placebo-controlled trial focused on the effects of S. salivarius M18 in children. The study demonstrated that supplementation with S. salivarius M18 led to improved indices of dental health, suggesting its potential benefit for pediatric oral care. The findings support its role in modulating the oral microbiome in young populations.
- https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2021.787908/pdf – This review discusses the role of S. salivarius M18 in oral health, emphasizing its ability to produce bacteriocins that inhibit pathogenic bacteria like S. mutans. It provides insights into the mechanisms by which this probiotic strain contributes to a healthier oral microbiome and helps prevent common oral diseases.
- https://pubmed.ncbi.nlm.nih.gov/39057009/ – This randomized controlled trial investigated the impact of S. salivarius M18 on gingival health and plaque accumulation. The study reported a significant reduction in gingival bleeding and dental plaque over a 3-month period, indicating its efficacy in improving periodontal health. The results suggest a beneficial role for S. salivarius M18 in managing gum inflammation.
