5 Streptococcus Thermophilus Benefits


Streptococcus thermophilus is a type of lactic acid probiotic bacteria that is commonly used when fermenting dairy foods like yogurts, cheese & kefir. Unlike Lactobacillus, it is thermophilic, meaning that it thrives at high temperatures.

S. thermophilus being a gram positive stain probiotic means it may also play a role in regulating the immune system, maintaining the balance of gut microbiota, assisting with lactose digestion and even skin health.

Lactose Intolerance

The 2011 study published in the peer-reviewed Journal of Biological Chemistry profiled the protein expression of Streptococcus thermophilus after its adaptation to the gastrointestinal tract of gnotobiotic rats.

The researchers from France found that S. thermophilus & L. Ddelbrueckii colonized the gastrointestinal tract of the rats and underwent an adaptation process, inducing the glycolysis pathway and forming lactate digestive enzymes in the cecum.

To put it simply, the study suggests that lactate produced by S. thermophilus could potentially help those with lactose intolerance but it's unclear if the strain could produce similar results in humans like it did with rats.


The 2009 study investigated the potential preventive effect of fermented milks containing EPS-producing Streptococcus thermophilus strains on an in vivo model of chronic gastritis.

Mice were fed fermented milks for 7 days before inducing gastritis with acetylsalicylic acid. Only mice treated with the EPS-producing S. thermophilus CRL 1190 fermented milk and later administered acetylsalicylic acid did not develop gastritis, showing a conserved gastric mucosa structure and a decrease in IFNgamma+- and increase in IL-10+-producing cells compared to the gastritis group.

Purified EPS from S. thermophilus CRL 1190 was also effective for preventing gastritis. The results indicate that fermented milk with S. thermophilus CRL 1190 or its EPS could be used in functional foods for preventing chronic gastritis.

Clostridium Difficile

The study published in the Gut Microbes journal aimed to assess the interactions between Streptococcus thermophilus and Clostridium difficile using in vitro and in vivo systems.

In vivo, treatment with viable S. thermophilus increased luminal levels of lactate in the cecum and significantly reduced weight loss, pathology, diarrhea, and toxin levels in mice infected with C. difficile infection.

The American researchers found significant inverse correlation between the levels of luminal lactate and abundance of C. difficile was observed, suggesting that lactate produced by S. thermophilus impacts the progression of C. difficile infection in mice but this may not translate into humans.

Skin Health

The old study from 1999 investigated the effects of Streptococcus thermophilus on ceramide levels in vitro on cultured human keratinocytes and in vivo on stratum corneum. 

The application of a base cream containing sonicated S. thermophilus in the skin of healthy volunteers for 7 days also led to a significant increase in skin ceramide amounts, likely due to the hydrolysis of sphingomyelin through bacterial neutral sphingomyelinase.

Inhibition of bacterial neutral sphingomyelinase activity with glutathione blocked the skin ceramide increase.

The researchers concluded that the topical application of a sonicated S. thermophilus preparation may improve lipid barrier function and increase resistance to xerosis.

Immune Health

The study published in the peer reviewed International Journal of Molecular Medicine journal examined the mechanism by which Streptococcus thermophilus ST28 suppresses the Th17 response in murine splenocytes stimulated with TGF-β plus IL-6.

Stimulation with TGF-β plus IL-6 increased IL-17 mRNA expression and production in splenocytes, but ST28 suppressed both. 

ST28 also increased IFN-γ mRNA expression and production. Anti-IFN-γ completely cancelled the suppressive effect of ST28 on IL-17 production, indicating that IFN-γ plays an important role in the effect.

Genomic DNA from ST28 suppressed IL-17 production via the Toll-like receptor 9 and Modulation of the Th1/Th17 balance may be one mechanism by which ST28 exerts an anti-inflammatory effect for immune health.

Closing Thoughts

My analysis found S. Thermophilus to produce exopolysaccharides, which have immunostimulatory and anti-ulcer effects, and produce lactic acid, which has antimicrobial and anti-inflammatory properties.

Its ability to produce lactic acid was also shown in two high quality studies to have a protective effect against Chronic Gastritis and Clostridium Difficile associated diarrhea but not in animal models.

Additionally, S. thermophilus may have a positive effect on skin health by increasing ceramide levels via topical application but the study for that claim was quite old.

Further research is needed to fully understand the potential health benefits of S. thermophilus. The content in this blog post is not medical advice and I not a Doctor.

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