Lactobacillus salivarius, a bacterium that lives in the human mouth, has shown promise for dental health, weight management, immunity, skin health, and other potential benefits. Learn more here.
What is Lactobacillus salivarius?
Lactobacillus salivarius is one of the most prevalent species in human saliva. It produces organic acids, such as lactic acid and acetic acid, from carbohydrates, which can inhibit the growth of surrounding microorganisms. It also produces hydrogen peroxide and other antimicrobial substances [1].
This bacterium is believed to stimulate the immune system, improve intestinal disease and promote well-being [2].
Health Benefits of L. salivarius
L. salivarius probiotic supplements have not been approved by the FDA for medical use. Supplements generally lack solid clinical research. Regulations set manufacturing standards for them but don’t guarantee that they’re safe or effective. Speak with your doctor before supplementing.
Possibly Effective For
1) Dental Health
L. salivarius beneficially changed the bacterial population of gum plaque in 66 volunteers [3].
L. salivarius increased resistance to caries risk factors in 64 healthy volunteers [4].
Oral administration of L. salivarius improved bad breath, showed beneficial effects on bleeding on probing from the periodontal pocket, and inhibited the reproduction of “bad” bacteria [5, 6, 1, 7].
Periodontal clinical parameters especially improved in smokers [8].
However, the authors of one study suggested that L. salivarius itself may possess an inherent cariogenic activity following adherence to the tooth surface [9].
Insufficient Evidence For
The following purported benefits are only supported by limited, low-quality clinical studies. There is insufficient evidence to support the use of L. salivarius for any of the below-listed uses. Remember to speak with a doctor before taking L. salivarius probiotic supplements, and never use them in place of something your doctor recommends or prescribes.
2) Obesity
L. salivarius increased the ratio of beneficial bacteria (Bacteroides, Prevotellae, and Porphyromonas) to Firmicutes-belonging bacteria in obese adolescents [10].
6-week supplementation of L. salivarius along with fructooligosaccharide (FOS) significantly reduced total cholesterol, “bad” (LDL) cholesterol, and triglycerides, and increased “good” (HDL) cholesterol in 45 human subjects. Blood inflammatory markers were also significantly reduced [11].
3) Immunity
Daily administration of L. salivarius to 40 healthy adults was safe and improved gut microbiota and different parameters related to immune response [12].
L. salivarius enhanced both innate and acquired immune responses in human cells [13].
4) Dermatitis
L. salivarius improved symptoms in children [14, 15], and adults with atopic dermatitis [16].
5) Mastitis
Oral administration of L. salivarius during late pregnancy prevented mastitis (breast infection) in 108 women [17].
Animal & Cell Research (Lacking Evidence)
No clinical evidence supports the use of L. salivarius for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies listed below should not be interpreted as supportive of any health benefit.
6) Antibacterial Activity
L. salivarius produces a bacteriocin, an antimicrobial substance, that can significantly protect mice against infection with the invasive foodborne pathogen Listeria monocytogenes [18].
7) H. pylori
L. salivarius suppressed H. pylori and reduced infection-induced inflammatory responses in mice [19].
This inhibition is strain specific, though, and a study showed that only 9 out of the 28 L. salivarius strains tested inhibited H. pylori growth [20].
8) Gut Inflammation
L. salivarius facilitates the recovery of the inflamed tissue in rat colitis, by ameliorating the production of inflammatory mediators, such as cytokines, including TNF-α and NO [21].
9) Diabetes
Treating diabetic mice with dead L. salivarius reversed gut microbial imbalance, restored mucosal antibacterial protein and lessened endotoxin levels [22].
10) Liver Function
Pretreatment with L. salivarius improved acute liver injury in rats [23].
L. salivarius exerts a good health-promoting effect in acute liver failure [24].
11) Asthma
L. salivarius decreased the secretion of proinflammatory cytokines and showed beneficial immunomodulatory activity in blood cells drawn from asthmatic subjects [25].
L. salivarius decreased allergen-induced airway response in mice [26].
L. salivarius alleviated the clinical symptoms, airway hyperreactivity and airway inflammation in mice with asthma [27].
Cancer Research
L. salivarius suppressed colon carcinogenesis in rats [28].
L. salivarius killed oral cancer cells and inhibits cancer growth in rats [29].
The relevance of these studies to human cancer is unknown.
Mechanisms
In cell and animal studies, researchers have observed that L. salivarius:
- Reduced inflammatory markers such as hs-CRP, interleukins IL-6, IL-1β, TNFα and TGF-β [11, 25].
- Reduced elevated ALT, AST and total bilirubin [23].
- Increased IL-10 and /or IFNγ [23, 25].
- Improved the Th1/Th2 balance in asthma mice [27].
- Reduced eosinophil influx, IgE, and eotaxin in asthma [26].
Safety
A formula containing L. salivarius was shown to be safe and well-tolerated in human clinical trials [12], including a trial with 6-month-old infants [30].
L. salivarius was shown to be nonpathogenic for mice, even in doses 10,000 times higher than those normally consumed by humans [31].
Use in patients with organ failure, immunocompromised status, and dysfunctional gut barrier mechanisms should be avoided as it can lead to infections. To avoid adverse effects, talk to your doctor before starting any new probiotic supplements.
